/*
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.jms;

import java.util.Enumeration;
import java.util.Properties;

/** The <CODE>Message</CODE> interface is the root interface of all JMS 
  * messages. It defines the message header and the <CODE>acknowledge</CODE> 
  * method used for all messages.
  *
  * <P>Most message-oriented middleware (MOM) products treat messages as 
  * lightweight entities that consist
  * of a header and a payload. The header contains fields used for message
  * routing and identification; the payload contains the application data
  * being sent.
  *
  * <P>Within this general form, the definition of a message varies
  * significantly across products. It would be quite difficult for the JMS API
  * to support all of these message models.
  *
  * <P>With this in mind, the JMS message model has the following goals:
  * <UL>
  *   <LI>Provide a single, unified message API
  *   <LI>Provide an API suitable for creating messages that match the
  *       format used by provider-native messaging applications
  *   <LI>Support the development of heterogeneous applications that span
  *       operating systems, machine architectures, and computer languages
  *   <LI>Support messages containing objects in the Java programming language
  *       ("Java objects")
  *   <LI>Support messages containing Extensible Markup Language (XML) pages
  * </UL>
  *
  * <P>JMS messages are composed of the following parts:
  * <UL>
  *   <LI>Header - All messages support the same set of header fields. 
  *       Header fields contain values used by both clients and providers to 
  *       identify and route messages.
  *   <LI>Properties - Each message contains a built-in facility for supporting
  *       application-defined property values. Properties provide an efficient 
  *       mechanism for supporting application-defined message filtering.
  *   <LI>Body - The JMS API defines several types of message body, which cover
  *       the majority of messaging styles currently in use.
  * </UL>
  *
  * <H4>Message Bodies</H4>
  *
  * <P>The JMS API defines five types of message body:
  * <UL>
  *   <LI>Stream - A <CODE>StreamMessage</CODE> object's message body contains 
  *       a stream of primitive values in the Java programming 
  *       language ("Java primitives"). It is filled and read sequentially.
  *   <LI>Map - A <CODE>MapMessage</CODE> object's message body contains a set 
  *       of name-value pairs, where names are <CODE>String</CODE> 
  *       objects, and values are Java primitives. The entries can be accessed 
  *       sequentially or randomly by name. The order of the entries is 
  *       undefined.
  *   <LI>Text - A <CODE>TextMessage</CODE> object's message body contains a 
  *       <CODE>java.lang.String</CODE> object. The inclusion 
  *       of this message type is based on our presumption that XML will 
  *       likely become a popular mechanism for representing content of all 
  *       kinds, including the content of JMS messages.
  *   <LI>Object - An <CODE>ObjectMessage</CODE> object's message body contains 
  *       a <CODE>Serializable</CODE> Java object.
  *   <LI>Bytes - A <CODE>BytesMessage</CODE> object's message body contains a 
  *       stream of uninterpreted bytes. This message type is for 
  *       literally encoding a body to match an existing message format. In 
  *       many cases, it is possible to use one of the other body types, 
  *       which are easier to use. Although the JMS API allows the use of  
  *       message properties with byte messages, they are typically not used,
  *       since the inclusion of properties may affect the format.
  * </UL>
  *
  * <H4>Message Headers</H4>
  *
  * <P>The <CODE>JMSCorrelationID</CODE> header field is used for linking one 
  * message with
  * another. It typically links a reply message with its requesting message.
  *
  * <P><CODE>JMSCorrelationID</CODE> can hold a provider-specific message ID,
  * an application-specific <CODE>String</CODE> object, or a provider-native 
  * <CODE>byte[]</CODE> value.
  *
  * <H4>Message Properties</H4>
  *
  * <P>A <CODE>Message</CODE> object contains a built-in facility for supporting
  * application-defined property values. In effect, this provides a mechanism 
  * for adding application-specific header fields to a message.
  *
  * <P>Properties allow an application, via message selectors, to have a JMS 
  * provider select, or filter, messages on its behalf using 
  * application-specific criteria.
  *
  * <P>Property names must obey the rules for a message selector identifier. 
  *
  * <P>Property values can be <CODE>boolean</CODE>, <CODE>byte</CODE>, 
  * <CODE>short</CODE>, <CODE>int</CODE>, <CODE>long</CODE>, <CODE>float</CODE>,
  * <CODE>double</CODE>, and <CODE>String</CODE>.
  *
  * <P>Property values are set prior to sending a message. When a client 
  * receives a message, its properties are in read-only mode. If a 
  * client attempts to set properties at this point, a 
  * <CODE>MessageNotWriteableException</CODE> is thrown. If 
  * <CODE>clearProperties</CODE> is called, the properties can now be both
  * read from and written to. Note that header fields are distinct from 
  * properties. Header fields are never in read-only mode. 
  *
  * <P>A property value may duplicate a value in a message's body, or it may 
  * not. Although JMS does not define a policy for what should or should not 
  * be made a property, application developers should note that JMS providers 
  * will likely handle data in a message's body more efficiently than data in 
  * a message's properties. For best performance, applications should use
  * message properties only when they need to customize a message's header. 
  * The primary reason for doing this is to support customized message 
  * selection.
  *
  * <P>Message properties support the following conversion table. The marked 
  * cases must be supported. The unmarked cases must throw a 
  * <CODE>JMSException</CODE>. The <CODE>String</CODE>-to-primitive conversions 
  * may throw a runtime exception if the
  * primitive's <CODE>valueOf</CODE> method does not accept the 
  * <CODE>String</CODE> as a valid representation of the primitive.
  *
  * <P>A value written as the row type can be read as the column type.
  *
  * <PRE>
  * |        | boolean byte short int long float double String 
  * |----------------------------------------------------------
  * |boolean |    X                                       X
  * |byte    |          X     X    X   X                  X 
  * |short   |                X    X   X                  X 
  * |int     |                     X   X                  X 
  * |long    |                         X                  X 
  * |float   |                               X     X      X 
  * |double  |                                     X      X 
  * |String  |    X     X     X    X   X     X     X      X 
  * |----------------------------------------------------------
  * </PRE>
  *
  * <P>In addition to the type-specific set/get methods for properties, JMS 
  * provides the <CODE>setObjectProperty</CODE> and 
  * <CODE>getObjectProperty</CODE> methods. These support the same set of 
  * property types using the objectified primitive values. Their purpose is 
  * to allow the decision of property type to made at execution time rather 
  * than at compile time. They support the same property value conversions.
  *
  * <P>The <CODE>setObjectProperty</CODE> method accepts values of class 
  * <CODE>Boolean</CODE>, <CODE>Byte</CODE>, <CODE>Short</CODE>, 
  * <CODE>Integer</CODE>, <CODE>Long</CODE>, <CODE>Float</CODE>, 
  * <CODE>Double</CODE>, and <CODE>String</CODE>. An attempt 
  * to use any other class must throw a <CODE>JMSException</CODE>.
  *
  * <P>The <CODE>getObjectProperty</CODE> method only returns values of class 
  * <CODE>Boolean</CODE>, <CODE>Byte</CODE>, <CODE>Short</CODE>, 
  * <CODE>Integer</CODE>, <CODE>Long</CODE>, <CODE>Float</CODE>, 
  * <CODE>Double</CODE>, and <CODE>String</CODE>.
  *
  * <P>The order of property values is not defined. To iterate through a 
  * message's property values, use <CODE>getPropertyNames</CODE> to retrieve 
  * a property name enumeration and then use the various property get methods 
  * to retrieve their values.
  *
  * <P>A message's properties are deleted by the <CODE>clearProperties</CODE>
  * method. This leaves the message with an empty set of properties.
  *
  * <P>Getting a property value for a name which has not been set returns a 
  * null value. Only the <CODE>getStringProperty</CODE> and 
  * <CODE>getObjectProperty</CODE> methods can return a null value. 
  * Attempting to read a null value as a primitive type must be treated as 
  * calling the primitive's corresponding <CODE>valueOf(String)</CODE> 
  * conversion method with a null value.
  *
  * <P>The JMS API reserves the <CODE>JMSX</CODE> property name prefix for JMS 
  * defined properties.
  * The full set of these properties is defined in the Java Message Service
  * specification. New JMS defined properties may be added in later versions 
  * of the JMS API.  Support for these properties is optional. The 
  * <CODE>String[] ConnectionMetaData.getJMSXPropertyNames</CODE> method 
  * returns the names of the JMSX properties supported by a connection.
  *
  * <P>JMSX properties may be referenced in message selectors whether or not
  * they are supported by a connection. If they are not present in a
  * message, they are treated like any other absent property.
  *
  * <P>JMSX properties defined in the specification as "set by provider on 
  * send" are available to both the producer and the consumers of the message. 
  * JMSX properties defined in the specification as "set by provider on 
  * receive" are available only to the consumers.
  *
  * <P><CODE>JMSXGroupID</CODE> and <CODE>JMSXGroupSeq</CODE> are standard 
  * properties that clients 
  * should use if they want to group messages. All providers must support them.
  * Unless specifically noted, the values and semantics of the JMSX properties 
  * are undefined.
  *
  * <P>The JMS API reserves the <CODE>JMS_<I>vendor_name</I></CODE> property 
  * name prefix for provider-specific properties. Each provider defines its own 
  * value for <CODE><I>vendor_name</I></CODE>. This is the mechanism a JMS 
  * provider uses to make its special per-message services available to a JMS 
  * client.
  *
  * <P>The purpose of provider-specific properties is to provide special 
  * features needed to integrate JMS clients with provider-native clients in a 
  * single JMS application. They should not be used for messaging between JMS 
  * clients.
  *
  * <H4>Provider Implementations of JMS Message Interfaces</H4>
  *
  * <P>The JMS API provides a set of message interfaces that define the JMS 
  * message 
  * model. It does not provide implementations of these interfaces.
  *
  * <P>Each JMS provider supplies a set of message factories with its 
  * <CODE>Session</CODE> object for creating instances of messages. This allows 
  * a provider to use message implementations tailored to its specific needs.
  *
  * <P>A provider must be prepared to accept message implementations that are 
  * not its own. They may not be handled as efficiently as its own 
  * implementation; however, they must be handled.
  *
  * <P>Note the following exception case when a provider is handling a foreign 
  * message implementation. If the foreign message implementation contains a 
  * <CODE>JMSReplyTo</CODE> header field that is set to a foreign destination 
  * implementation, the provider is not required to handle or preserve the 
  * value of this header field. 
  *
  * <H4>Message Selectors</H4>
  *
  * <P>A JMS message selector allows a client to specify, by
  * header field references and property references, the
  * messages it is interested in. Only messages whose header 
  * and property values
  * match the 
  * selector are delivered. What it means for a message not to be delivered
  * depends on the <CODE>MessageConsumer</CODE> being used (see 
  * {@link javax.jms.QueueReceiver QueueReceiver} and 
  * {@link javax.jms.TopicSubscriber TopicSubscriber}).
  *
  * <P>Message selectors cannot reference message body values.
  *
  * <P>A message selector matches a message if the selector evaluates to 
  * true when the message's header field values and property values are 
  * substituted for their corresponding identifiers in the selector.
  *
  * <P>A message selector is a <CODE>String</CODE> whose syntax is based on a 
  * subset of 
  * the SQL92 conditional expression syntax. If the value of a message selector 
  * is an empty string, the value is treated as a null and indicates that there 
  * is no message selector for the message consumer. 
  *
  * <P>The order of evaluation of a message selector is from left to right 
  * within precedence level. Parentheses can be used to change this order.
  *
  * <P>Predefined selector literals and operator names are shown here in 
  * uppercase; however, they are case insensitive.
  *
  * <P>A selector can contain:
  *
  * <UL>
  *   <LI>Literals:
  *   <UL>
  *     <LI>A string literal is enclosed in single quotes, with a single quote 
  *         represented by doubled single quote; for example, 
  *         <CODE>'literal'</CODE> and <CODE>'literal''s'</CODE>. Like 
  *         string literals in the Java programming language, these use the 
  *         Unicode character encoding.
  *     <LI>An exact numeric literal is a numeric value without a decimal 
  *         point, such as <CODE>57</CODE>, <CODE>-957</CODE>, and  
  *         <CODE>+62</CODE> numbers in the range of <CODE>long</CODE> are 
  *         supported. Exact numeric literals use the integer literal 
  *         syntax of the Java programming language.
  *     <LI>An approximate numeric literal is a numeric value in scientific 
  *         notation, such as <CODE>7E3</CODE> and <CODE>-57.9E2</CODE>, or a 
  *         numeric value with a decimal, such as <CODE>7.</CODE>, 
  *         <CODE>-95.7</CODE>, and <CODE>+6.2</CODE> numbers in the range of 
  *         <CODE>double</CODE> are supported. Approximate literals use the 
  *         floating-point literal syntax of the Java programming language.
  *     <LI>The boolean literals <CODE>TRUE</CODE> and <CODE>FALSE</CODE>.
  *   </UL>
  *   <LI>Identifiers:
  *   <UL>
  *     <LI>An identifier is an unlimited-length sequence of letters 
  *         and digits, the first of which must be a letter. A letter is any 
  *         character for which the method <CODE>Character.isJavaLetter</CODE>
  *         returns true. This includes <CODE>'_'</CODE> and <CODE>'$'</CODE>.
  *         A letter or digit is any character for which the method 
  *         <CODE>Character.isJavaLetterOrDigit</CODE> returns true.
  *     <LI>Identifiers cannot be the names <CODE>NULL</CODE>, 
  *         <CODE>TRUE</CODE>, and <CODE>FALSE</CODE>.
  *     <LI>Identifiers cannot be <CODE>NOT</CODE>, <CODE>AND</CODE>, 
  *         <CODE>OR</CODE>, <CODE>BETWEEN</CODE>, <CODE>LIKE</CODE>, 
  *         <CODE>IN</CODE>, <CODE>IS</CODE>, or <CODE>ESCAPE</CODE>.
  *     <LI>Identifiers are either header field references or property 
  *         references.  The type of a property value in a message selector 
  *         corresponds to the type used to set the property. If a property 
  *         that does not exist in a message is referenced, its value is 
  *         <CODE>NULL</CODE>.
  *     <LI>The conversions that apply to the get methods for properties do not
  *         apply when a property is used in a message selector expression.
  *         For example, suppose you set a property as a string value, as in the
  *         following:
  *         <PRE>myMessage.setStringProperty("NumberOfOrders", "2");</PRE>
  *         The following expression in a message selector would evaluate to 
  *         false, because a string cannot be used in an arithmetic expression:
  *         <PRE>"NumberOfOrders > 1"</PRE>
  *     <LI>Identifiers are case-sensitive.
  *     <LI>Message header field references are restricted to 
  *         <CODE>JMSDeliveryMode</CODE>, <CODE>JMSPriority</CODE>, 
  *         <CODE>JMSMessageID</CODE>, <CODE>JMSTimestamp</CODE>, 
  *         <CODE>JMSCorrelationID</CODE>, and <CODE>JMSType</CODE>. 
  *         <CODE>JMSMessageID</CODE>, <CODE>JMSCorrelationID</CODE>, and 
  *         <CODE>JMSType</CODE> values may be null and if so are treated as a 
  *         <CODE>NULL</CODE> value.
  *     <LI>Any name beginning with <CODE>'JMSX'</CODE> is a JMS defined  
  *         property name.
  *     <LI>Any name beginning with <CODE>'JMS_'</CODE> is a provider-specific 
  *         property name.
  *     <LI>Any name that does not begin with <CODE>'JMS'</CODE> is an 
  *         application-specific property name.
  *   </UL>
  *   <LI>White space is the same as that defined for the Java programming
  *       language: space, horizontal tab, form feed, and line terminator.
  *   <LI>Expressions: 
  *   <UL>
  *     <LI>A selector is a conditional expression; a selector that evaluates 
  *         to <CODE>true</CODE> matches; a selector that evaluates to 
  *         <CODE>false</CODE> or unknown does not match.
  *     <LI>Arithmetic expressions are composed of themselves, arithmetic 
  *         operations, identifiers (whose value is treated as a numeric 
  *         literal), and numeric literals.
  *     <LI>Conditional expressions are composed of themselves, comparison 
  *         operations, and logical operations.
  *   </UL>
  *   <LI>Standard bracketing <CODE>()</CODE> for ordering expression evaluation
  *      is supported.
  *   <LI>Logical operators in precedence order: <CODE>NOT</CODE>, 
  *       <CODE>AND</CODE>, <CODE>OR</CODE>
  *   <LI>Comparison operators: <CODE>=</CODE>, <CODE>></CODE>, <CODE>>=</CODE>,
  *       <CODE><</CODE>, <CODE><=</CODE>, <CODE><></CODE> (not equal)
  *   <UL>
  *     <LI>Only like type values can be compared. One exception is that it 
  *         is valid to compare exact numeric values and approximate numeric 
  *         values; the type conversion required is defined by the rules of 
  *         numeric promotion in the Java programming language. If the 
  *         comparison of non-like type values is attempted, the value of the 
  *         operation is false. If either of the type values evaluates to 
  *         <CODE>NULL</CODE>, the value of the expression is unknown.   
  *     <LI>String and boolean comparison is restricted to <CODE>=</CODE> and 
  *         <CODE><></CODE>. Two strings are equal 
  *         if and only if they contain the same sequence of characters.
  *   </UL>
  *   <LI>Arithmetic operators in precedence order:
  *   <UL>
  *     <LI><CODE>+</CODE>, <CODE>-</CODE> (unary)
  *     <LI><CODE>*</CODE>, <CODE>/</CODE> (multiplication and division)
  *     <LI><CODE>+</CODE>, <CODE>-</CODE> (addition and subtraction)
  *     <LI>Arithmetic operations must use numeric promotion in the Java 
  *         programming language.
  *   </UL>
  *   <LI><CODE><I>arithmetic-expr1</I> [NOT] BETWEEN <I>arithmetic-expr2</I> 
  *       AND <I>arithmetic-expr3</I></CODE> (comparison operator)
  *   <UL>
  *     <LI><CODE>"age BETWEEN 15 AND 19"</CODE> is 
  *         equivalent to 
  *         <CODE>"age >= 15 AND age <= 19"</CODE>
  *     <LI><CODE>"age NOT BETWEEN 15 AND 19"</CODE> 
  *         is equivalent to 
  *         <CODE>"age < 15 OR age > 19"</CODE>
  *   </UL>
  *   <LI><CODE><I>identifier</I> [NOT] IN (<I>string-literal1</I>, 
  *       <I>string-literal2</I>,...)</CODE> (comparison operator where 
  *       <CODE><I>identifier</I></CODE> has a <CODE>String</CODE> or 
  *       <CODE>NULL</CODE> value)
  *   <UL>
  *     <LI><CODE>"Country IN (' UK', 'US', 'France')"</CODE>
  *         is true for 
  *         <CODE>'UK'</CODE> and false for <CODE>'Peru'</CODE> it is 
  *         equivalent to the expression 
  *         <CODE>"(Country = ' UK') OR (Country = ' US') OR (Country = ' France')"</CODE>
  *     <LI><CODE>"Country NOT IN (' UK', 'US', 'France')"</CODE> 
  *         is false for <CODE>'UK'</CODE> and true for <CODE>'Peru'</CODE> it 
  *         is equivalent to the expression 
  *         <CODE>"NOT ((Country = ' UK') OR (Country = ' US') OR (Country = ' France'))"</CODE>
  *     <LI>If identifier of an <CODE>IN</CODE> or <CODE>NOT IN</CODE> 
  *         operation is <CODE>NULL</CODE>, the value of the operation is 
  *         unknown.
  *   </UL>
  *   <LI><CODE><I>identifier</I> [NOT] LIKE <I>pattern-value</I> [ESCAPE 
  *       <I>escape-character</I>]</CODE> (comparison operator, where 
  *       <CODE><I>identifier</I></CODE> has a <CODE>String</CODE> value; 
  *       <CODE><I>pattern-value</I></CODE> is a string literal where 
  *       <CODE>'_'</CODE> stands for any single character; <CODE>'%'</CODE> 
  *       stands for any sequence of characters, including the empty sequence; 
  *       and all other characters stand for themselves. The optional 
  *       <CODE><I>escape-character</I></CODE> is a single-character string 
  *       literal whose character is used to escape the special meaning of the 
  *       <CODE>'_'</CODE> and <CODE>'%'</CODE> in 
  *       <CODE><I>pattern-value</I></CODE>.)
  *   <UL>
  *     <LI><CODE>"phone LIKE '12%3'"</CODE> is true for 
  *         <CODE>'123'</CODE> or <CODE>'12993'</CODE> and false for 
  *         <CODE>'1234'</CODE>
  *     <LI><CODE>"word LIKE 'l_se'"</CODE> is true for 
  *         <CODE>'lose'</CODE> and false for <CODE>'loose'</CODE>
  *     <LI><CODE>"underscored LIKE '\_%' ESCAPE '\'"</CODE>
  *          is true for <CODE>'_foo'</CODE> and false for <CODE>'bar'</CODE>
  *     <LI><CODE>"phone NOT LIKE '12%3'"</CODE> is false for 
  *         <CODE>'123'</CODE> or <CODE>'12993'</CODE> and true for 
  *         <CODE>'1234'</CODE>
  *     <LI>If <CODE><I>identifier</I></CODE> of a <CODE>LIKE</CODE> or 
  *         <CODE>NOT LIKE</CODE> operation is <CODE>NULL</CODE>, the value 
  *         of the operation is unknown.
  *   </UL>
  *   <LI><CODE><I>identifier</I> IS NULL</CODE> (comparison operator that tests
  *       for a null header field value or a missing property value)
  *   <UL>
  *     <LI><CODE>"prop_name IS NULL"</CODE>
  *   </UL>
  *   <LI><CODE><I>identifier</I> IS NOT NULL</CODE> (comparison operator that
  *       tests for the existence of a non-null header field value or a property
  *       value)
  *   <UL>
  *     <LI><CODE>"prop_name IS NOT NULL"</CODE>
  *   </UL>
  *
  * <P>JMS providers are required to verify the syntactic correctness of a 
  *    message selector at the time it is presented. A method that provides a 
  * syntactically incorrect selector must result in a <CODE>JMSException</CODE>.
  *
  * <P>The following message selector selects messages with a message type 
  * of car and color of blue and weight greater than 2500 pounds:
  *
  * <PRE>"JMSType = 'car' AND color = 'blue' AND weight > 2500"</PRE>
  *
  * <H4>Null Values</H4>
  *
  * <P>As noted above, property values may be <CODE>NULL</CODE>. The evaluation 
  * of selector expressions containing <CODE>NULL</CODE> values is defined by 
  * SQL92 <CODE>NULL</CODE> semantics. A brief description of these semantics 
  * is provided here.
  *
  * <P>SQL treats a <CODE>NULL</CODE> value as unknown. Comparison or arithmetic
  * with an unknown value always yields an unknown value.
  *
  * <P>The <CODE>IS NULL</CODE> and <CODE>IS NOT NULL</CODE> operators convert 
  * an unknown value into the respective <CODE>TRUE</CODE> and 
  * <CODE>FALSE</CODE> values.
  *
  * <P>The boolean operators use three-valued logic as defined by the 
  * following tables:
  *
  * <P><B>The definition of the <CODE>AND</CODE> operator</B>
  *
  * <PRE>
  * | AND  |   T   |   F   |   U
  * +------+-------+-------+-------
  * |  T   |   T   |   F   |   U
  * |  F   |   F   |   F   |   F
  * |  U   |   U   |   F   |   U
  * +------+-------+-------+-------
  * </PRE>
  *
  * <P><B>The definition of the <CODE>OR</CODE> operator</B>
  *
  * <PRE>
  * | OR   |   T   |   F   |   U
  * +------+-------+-------+--------
  * |  T   |   T   |   T   |   T
  * |  F   |   T   |   F   |   U
  * |  U   |   T   |   U   |   U
  * +------+-------+-------+------- 
  * </PRE> 
  *
  * <P><B>The definition of the <CODE>NOT</CODE> operator</B>
  *
  * <PRE>
  * | NOT
  * +------+------
  * |  T   |   F
  * |  F   |   T
  * |  U   |   U
  * +------+-------
  * </PRE>
  *
  * <H4>Special Notes</H4>
  *
  * <P>When used in a message selector, the <CODE>JMSDeliveryMode</CODE> header 
  *    field is treated as having the values <CODE>'PERSISTENT'</CODE> and 
  *    <CODE>'NON_PERSISTENT'</CODE>.
  *
  * <P>Date and time values should use the standard <CODE>long</CODE> 
  *    millisecond value. When a date or time literal is included in a message 
  *    selector, it should be an integer literal for a millisecond value. The 
  *    standard way to produce millisecond values is to use 
  *    <CODE>java.util.Calendar</CODE>.
  *
  * <P>Although SQL supports fixed decimal comparison and arithmetic, JMS 
  *    message selectors do not. This is the reason for restricting exact 
  *    numeric literals to those without a decimal (and the addition of 
  *    numerics with a decimal as an alternate representation for 
  *    approximate numeric values).
  *
  * <P>SQL comments are not supported.
  *
  * @version     1.0 - 6 August 1998
  * @author      Mark Hapner
  * @author      Rich Burridge
  *
  * @see         javax.jms.MessageConsumer#receive()
  * @see         javax.jms.MessageConsumer#receive(long)
  * @see         javax.jms.MessageConsumer#receiveNoWait()
  * @see         javax.jms.MessageListener#onMessage(Message)
  * @see         javax.jms.BytesMessage
  * @see         javax.jms.MapMessage
  * @see         javax.jms.ObjectMessage
  * @see         javax.jms.StreamMessage
  * @see         javax.jms.TextMessage
  */

public interface Message {

    /** The message producer's default delivery mode is <CODE>PERSISTENT</CODE>.
     *
     *  @see DeliveryMode#PERSISTENT
     */
    static final int DEFAULT_DELIVERY_MODE = DeliveryMode.PERSISTENT;

    /** The message producer's default priority is 4. 
     */
    static final int DEFAULT_PRIORITY = 4;

    /** The message producer's default time to live is unlimited; the message 
     *  never expires. 
     */
    static final long DEFAULT_TIME_TO_LIVE = 0;


    /** Gets the message ID.
      *
      * <P>The <CODE>JMSMessageID</CODE> header field contains a value that 
      * uniquely identifies each message sent by a provider.
      *  
      * <P>When a message is sent, <CODE>JMSMessageID</CODE> can be ignored. 
      * When the <CODE>send</CODE> or <CODE>publish</CODE> method returns, it 
      * contains a provider-assigned value.
      *
      * <P>A <CODE>JMSMessageID</CODE> is a <CODE>String</CODE> value that 
      * should function as a 
      * unique key for identifying messages in a historical repository. 
      * The exact scope of uniqueness is provider-defined. It should at 
      * least cover all messages for a specific installation of a 
      * provider, where an installation is some connected set of message 
      * routers.
      *
      * <P>All <CODE>JMSMessageID</CODE> values must start with the prefix 
      * <CODE>'ID:'</CODE>. 
      * Uniqueness of message ID values across different providers is 
      * not required.
      *
      * <P>Since message IDs take some effort to create and increase a
      * message's size, some JMS providers may be able to optimize message
      * overhead if they are given a hint that the message ID is not used by
      * an application. By calling the 
      * <CODE>MessageProducer.setDisableMessageID</CODE> method, a JMS client 
      * enables this potential optimization for all messages sent by that 
      * message producer. If the JMS provider accepts this
      * hint, these messages must have the message ID set to null; if the 
      * provider ignores the hint, the message ID must be set to its normal 
      * unique value.
      *
      * @return the message ID
      *
      * @exception JMSException if the JMS provider fails to get the message ID 
      *                         due to some internal error.
      * @see javax.jms.Message#setJMSMessageID(String)
      * @see javax.jms.MessageProducer#setDisableMessageID(boolean)
      */ 
 
    String
    getJMSMessageID() throws JMSException;


    /** Sets the message ID.
      *  
      * <P>JMS providers set this field when a message is sent. This method
      * can be used to change the value for a message that has been received.
      *
      * @param id the ID of the message
      *
      * @exception JMSException if the JMS provider fails to set the message ID 
      *                         due to some internal error.
      *
      * @see javax.jms.Message#getJMSMessageID()
      */ 

    void
    setJMSMessageID(String id) throws JMSException;


    /** Gets the message timestamp.
      *  
      * <P>The <CODE>JMSTimestamp</CODE> header field contains the time a 
      * message was 
      * handed off to a provider to be sent. It is not the time the 
      * message was actually transmitted, because the actual send may occur 
      * later due to transactions or other client-side queueing of messages.
      *
      * <P>When a message is sent, <CODE>JMSTimestamp</CODE> is ignored. When 
      * the <CODE>send</CODE> or <CODE>publish</CODE>
      * method returns, it contains a a time value somewhere in the interval 
      * between the call and the return. The value is in the format of a normal 
      * millis time value in the Java programming language.
      *
      * <P>Since timestamps take some effort to create and increase a 
      * message's size, some JMS providers may be able to optimize message 
      * overhead if they are given a hint that the timestamp is not used by an 
      * application. By calling the
      * <CODE>MessageProducer.setDisableMessageTimestamp</CODE> method, a JMS 
      * client enables this potential optimization for all messages sent by 
      * that message producer. If the JMS provider accepts this
      * hint, these messages must have the timestamp set to zero; if the 
      * provider ignores the hint, the timestamp must be set to its normal 
      * value.
      *
      * @return the message timestamp
      *
      * @exception JMSException if the JMS provider fails to get the timestamp
      *                         due to some internal error.
      *
      * @see javax.jms.Message#setJMSTimestamp(long)
      * @see javax.jms.MessageProducer#setDisableMessageTimestamp(boolean)
      */

    long
    getJMSTimestamp() throws JMSException;


    /** Sets the message timestamp.
      *  
      * <P>JMS providers set this field when a message is sent. This method
      * can be used to change the value for a message that has been received.
      *
      * @param timestamp the timestamp for this message
      *  
      * @exception JMSException if the JMS provider fails to set the timestamp
      *                         due to some internal error.
      *
      * @see javax.jms.Message#getJMSTimestamp()
      */

    void
    setJMSTimestamp(long timestamp) throws JMSException;


    /** Gets the correlation ID as an array of bytes for the message.
      *  
      * <P>The use of a <CODE>byte[]</CODE> value for 
      * <CODE>JMSCorrelationID</CODE> is non-portable.
      *
      * @return the correlation ID of a message as an array of bytes
      *
      * @exception JMSException if the JMS provider fails to get the correlation
      *                         ID due to some internal error.
      *  
      * @see javax.jms.Message#setJMSCorrelationID(String)
      * @see javax.jms.Message#getJMSCorrelationID()
      * @see javax.jms.Message#setJMSCorrelationIDAsBytes(byte[])
      */

    byte []
    getJMSCorrelationIDAsBytes() throws JMSException;


    /** Sets the correlation ID as an array of bytes for the message.
      * 
      * <P>The array is copied before the method returns, so
      * future modifications to the array will not alter this message header.
      *  
      * <P>If a provider supports the native concept of correlation ID, a 
      * JMS client may need to assign specific <CODE>JMSCorrelationID</CODE> 
      * values to match those expected by native messaging clients. 
      * JMS providers without native correlation ID values are not required to 
      * support this method and its corresponding get method; their 
      * implementation may throw a
      * <CODE>java.lang.UnsupportedOperationException</CODE>. 
      *
      * <P>The use of a <CODE>byte[]</CODE> value for 
      * <CODE>JMSCorrelationID</CODE> is non-portable.
      *
      * @param correlationID the correlation ID value as an array of bytes
      *  
      * @exception JMSException if the JMS provider fails to set the correlation
      *                         ID due to some internal error.
      *  
      * @see javax.jms.Message#setJMSCorrelationID(String)
      * @see javax.jms.Message#getJMSCorrelationID()
      * @see javax.jms.Message#getJMSCorrelationIDAsBytes()
      */

    void
    setJMSCorrelationIDAsBytes(byte[] correlationID) throws JMSException;


    /** Sets the correlation ID for the message.
      *  
      * <P>A client can use the <CODE>JMSCorrelationID</CODE> header field to 
      * link one message with another. A typical use is to link a response 
      * message with its request message.
      *  
      * <P><CODE>JMSCorrelationID</CODE> can hold one of the following:
      *    <UL>
      *      <LI>A provider-specific message ID
      *      <LI>An application-specific <CODE>String</CODE>
      *      <LI>A provider-native <CODE>byte[]</CODE> value
      *    </UL>
      *  
      * <P>Since each message sent by a JMS provider is assigned a message ID
      * value, it is convenient to link messages via message ID. All message ID
      * values must start with the <CODE>'ID:'</CODE> prefix.
      *  
      * <P>In some cases, an application (made up of several clients) needs to
      * use an application-specific value for linking messages. For instance,
      * an application may use <CODE>JMSCorrelationID</CODE> to hold a value 
      * referencing some external information. Application-specified values 
      * must not start with the <CODE>'ID:'</CODE> prefix; this is reserved for 
      * provider-generated message ID values.
      *  
      * <P>If a provider supports the native concept of correlation ID, a JMS
      * client may need to assign specific <CODE>JMSCorrelationID</CODE> values 
      * to match those expected by clients that do not use the JMS API. A 
      * <CODE>byte[]</CODE> value is used for this
      * purpose. JMS providers without native correlation ID values are not
      * required to support <CODE>byte[]</CODE> values. The use of a 
      * <CODE>byte[]</CODE> value for <CODE>JMSCorrelationID</CODE> is 
      * non-portable.
      *  
      * @param correlationID the message ID of a message being referred to
      *  
      * @exception JMSException if the JMS provider fails to set the correlation
      *                         ID due to some internal error.
      *  
      * @see javax.jms.Message#getJMSCorrelationID()
      * @see javax.jms.Message#getJMSCorrelationIDAsBytes()
      * @see javax.jms.Message#setJMSCorrelationIDAsBytes(byte[])
      */ 

    void
    setJMSCorrelationID(String correlationID) throws JMSException;


    /** Gets the correlation ID for the message.
      *  
      * <P>This method is used to return correlation ID values that are 
      * either provider-specific message IDs or application-specific 
      * <CODE>String</CODE> values.
      *
      * @return the correlation ID of a message as a <CODE>String</CODE>
      *
      * @exception JMSException if the JMS provider fails to get the correlation
      *                         ID due to some internal error.
      *
      * @see javax.jms.Message#setJMSCorrelationID(String)
      * @see javax.jms.Message#getJMSCorrelationIDAsBytes()
      * @see javax.jms.Message#setJMSCorrelationIDAsBytes(byte[])
      */ 
 
    String
    getJMSCorrelationID() throws JMSException;


    /** Gets the <CODE>Destination</CODE> object to which a reply to this 
      * message should be sent.
      *  
      * @return <CODE>Destination</CODE> to which to send a response to this 
      *         message
      *
      * @exception JMSException if the JMS provider fails to get the  
      *                         <CODE>JMSReplyTo</CODE> destination due to some 
      *                         internal error.
      *
      * @see javax.jms.Message#setJMSReplyTo(Destination)
      */ 
 
    Destination
    getJMSReplyTo() throws JMSException;


    /** Sets the <CODE>Destination</CODE> object to which a reply to this 
      * message should be sent.
      *  
      * <P>The <CODE>JMSReplyTo</CODE> header field contains the destination 
      * where a reply 
      * to the current message should be sent. If it is null, no reply is 
      * expected. The destination may be either a <CODE>Queue</CODE> object or
      * a <CODE>Topic</CODE> object.
      *
      * <P>Messages sent with a null <CODE>JMSReplyTo</CODE> value may be a 
      * notification of some event, or they may just be some data the sender 
      * thinks is of interest.
      *
      * <P>Messages with a <CODE>JMSReplyTo</CODE> value typically expect a 
      * response. A response is optional; it is up to the client to decide.  
      * These messages are called requests. A message sent in response to a 
      * request is called a reply.
      *
      * <P>In some cases a client may wish to match a request it sent earlier 
      * with a reply it has just received. The client can use the 
      * <CODE>JMSCorrelationID</CODE> header field for this purpose.
      *
      * @param replyTo <CODE>Destination</CODE> to which to send a response to 
      *                this message
      *
      * @exception JMSException if the JMS provider fails to set the  
      *                         <CODE>JMSReplyTo</CODE> destination due to some 
      *                         internal error.
      *
      * @see javax.jms.Message#getJMSReplyTo()
      */ 

    void
    setJMSReplyTo(Destination replyTo) throws JMSException;


    /** Gets the <CODE>Destination</CODE> object for this message.
      *  
      * <P>The <CODE>JMSDestination</CODE> header field contains the 
      * destination to which the message is being sent.
      *  
      * <P>When a message is sent, this field is ignored. After completion
      * of the <CODE>send</CODE> or <CODE>publish</CODE> method, the field 
      * holds the destination specified by the method.
      *  
      * <P>When a message is received, its <CODE>JMSDestination</CODE> value 
      * must be equivalent to the value assigned when it was sent.
      *
      * @return the destination of this message
      *  
      * @exception JMSException if the JMS provider fails to get the destination
      *                         due to some internal error.
      *  
      * @see javax.jms.Message#setJMSDestination(Destination)
      */ 

    Destination
    getJMSDestination() throws JMSException;


    /** Sets the <CODE>Destination</CODE> object for this message.
      *  
      * <P>JMS providers set this field when a message is sent. This method 
      * can be used to change the value for a message that has been received.
      *
      * @param destination the destination for this message
      *  
      * @exception JMSException if the JMS provider fails to set the destination
      *                         due to some internal error.
      *  
      * @see javax.jms.Message#getJMSDestination()
      */ 

    void
    setJMSDestination(Destination destination) throws JMSException;


    /** Gets the <CODE>DeliveryMode</CODE> value specified for this message.
      *  
      * @return the delivery mode for this message
      *  
      * @exception JMSException if the JMS provider fails to get the 
      *                         delivery mode due to some internal error.
      *  
      * @see javax.jms.Message#setJMSDeliveryMode(int)
      * @see javax.jms.DeliveryMode
      */ 
 
    int
    getJMSDeliveryMode() throws JMSException;
 
 
    /** Sets the <CODE>DeliveryMode</CODE> value for this message.
      *  
      * <P>JMS providers set this field when a message is sent. This method 
      * can be used to change the value for a message that has been received.
      *
      * @param deliveryMode the delivery mode for this message
      *  
      * @exception JMSException if the JMS provider fails to set the 
      *                         delivery mode due to some internal error.
      *  
      * @see javax.jms.Message#getJMSDeliveryMode()
      * @see javax.jms.DeliveryMode
      */ 
 
    void 
    setJMSDeliveryMode(int deliveryMode) throws JMSException;


    /** Gets an indication of whether this message is being redelivered.
      *
      * <P>If a client receives a message with the <CODE>JMSRedelivered</CODE> 
      * field set,
      * it is likely, but not guaranteed, that this message was delivered
      * earlier but that its receipt was not acknowledged
      * at that time.
      *
      * @return true if this message is being redelivered
      *  
      * @exception JMSException if the JMS provider fails to get the redelivered
      *                         state due to some internal error.
      *
      * @see javax.jms.Message#setJMSRedelivered(boolean)
      */ 
 
    boolean
    getJMSRedelivered() throws JMSException;
 
 
    /** Specifies whether this message is being redelivered.
      *  
      * <P>This field is set at the time the message is delivered. This
      * method can be used to change the value for a message that has
      * been received.
      *
      * @param redelivered an indication of whether this message is being
      * redelivered
      *  
      * @exception JMSException if the JMS provider fails to set the redelivered
      *                         state due to some internal error.
      *
      * @see javax.jms.Message#getJMSRedelivered()
      */ 
 
    void
    setJMSRedelivered(boolean redelivered) throws JMSException;


    /** Gets the message type identifier supplied by the client when the
      * message was sent.
      *
      * @return the message type
      *  
      * @exception JMSException if the JMS provider fails to get the message 
      *                         type due to some internal error.
      *
      * @see javax.jms.Message#setJMSType(String)
      */
       
    String
    getJMSType() throws JMSException;


    /** Sets the message type.
      *
      * <P>Some JMS providers use a message repository that contains the 
      * definitions of messages sent by applications. The <CODE>JMSType</CODE> 
      * header field may reference a message's definition in the provider's
      * repository.
      *
      * <P>The JMS API does not define a standard message definition repository,
      * nor does it define a naming policy for the definitions it contains. 
      *
      * <P>Some messaging systems require that a message type definition for 
      * each application message be created and that each message specify its 
      * type. In order to work with such JMS providers, JMS clients should 
      * assign a value to <CODE>JMSType</CODE>, whether the application makes 
      * use of it or not. This ensures that the field is properly set for those 
      * providers that require it.
      *
      * <P>To ensure portability, JMS clients should use symbolic values for 
      * <CODE>JMSType</CODE> that can be configured at installation time to the 
      * values defined in the current provider's message repository. If string 
      * literals are used, they may not be valid type names for some JMS 
      * providers.
      *
      * @param type the message type
      *  
      * @exception JMSException if the JMS provider fails to set the message 
      *                         type due to some internal error.
      *
      * @see javax.jms.Message#getJMSType()
      */

    void 
    setJMSType(String type) throws JMSException;


    /** Gets the message's expiration value.
      *  
      * <P>When a message is sent, the <CODE>JMSExpiration</CODE> header field 
      * is left unassigned. After completion of the <CODE>send</CODE> or 
      * <CODE>publish</CODE> method, it holds the expiration time of the
      * message. This is the sum of the time-to-live value specified by the
      * client and the GMT at the time of the <CODE>send</CODE> or 
      * <CODE>publish</CODE>.
      *
      * <P>If the time-to-live is specified as zero, <CODE>JMSExpiration</CODE> 
      * is set to zero to indicate that the message does not expire.
      *
      * <P>When a message's expiration time is reached, a provider should
      * discard it. The JMS API does not define any form of notification of 
      * message expiration.
      *
      * <P>Clients should not receive messages that have expired; however,
      * the JMS API does not guarantee that this will not happen.
      *
      * @return the time the message expires, which is the sum of the
      * time-to-live value specified by the client and the GMT at the
      * time of the send
      *  
      * @exception JMSException if the JMS provider fails to get the message 
      *                         expiration due to some internal error.
      *
      * @see javax.jms.Message#setJMSExpiration(long)
      */ 
 
    long
    getJMSExpiration() throws JMSException;
 
 
    /** Sets the message's expiration value.
      *
      * <P>JMS providers set this field when a message is sent. This method 
      * can be used to change the value for a message that has been received.
      *  
      * @param expiration the message's expiration time
      *  
      * @exception JMSException if the JMS provider fails to set the message 
      *                         expiration due to some internal error.
      *
      * @see javax.jms.Message#getJMSExpiration() 
      */
 
    void
    setJMSExpiration(long expiration) throws JMSException;


    /** Gets the message priority level.
      *  
      * <P>The JMS API defines ten levels of priority value, with 0 as the 
      * lowest
      * priority and 9 as the highest. In addition, clients should consider
      * priorities 0-4 as gradations of normal priority and priorities 5-9
      * as gradations of expedited priority.
      *  
      * <P>The JMS API does not require that a provider strictly implement 
      * priority 
      * ordering of messages; however, it should do its best to deliver 
      * expedited messages ahead of normal messages.
      *  
      * @return the default message priority
      *  
      * @exception JMSException if the JMS provider fails to get the message 
      *                         priority due to some internal error.
      *
      * @see javax.jms.Message#setJMSPriority(int) 
      */ 

    int
    getJMSPriority() throws JMSException;


    /** Sets the priority level for this message.
      *  
      * <P>JMS providers set this field when a message is sent. This method 
      * can be used to change the value for a message that has been received.
      *
      * @param priority the priority of this message
      *  
      * @exception JMSException if the JMS provider fails to set the message 
      *                         priority due to some internal error.
      *
      * @see javax.jms.Message#getJMSPriority() 
      */ 

    void
    setJMSPriority(int priority) throws JMSException;


    /** Clears a message's properties.
      *
      * <P>The message's header fields and body are not cleared.
      *
      * @exception JMSException if the JMS provider fails to clear the message 
      *                         properties due to some internal error.
      */ 

    void
    clearProperties() throws JMSException;


    /** Indicates whether a property value exists.
      *
      * @param name the name of the property to test
      *
      * @return true if the property exists
      *  
      * @exception JMSException if the JMS provider fails to determine if the 
      *                         property exists due to some internal error.
      */

    boolean
    propertyExists(String name) throws JMSException;


    /** Returns the value of the <CODE>boolean</CODE> property with the  
      * specified name.
      *  
      * @param name the name of the <CODE>boolean</CODE> property
      *  
      * @return the <CODE>boolean</CODE> property value for the specified name
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid. 
      */ 

    boolean
    getBooleanProperty(String name) throws JMSException;


    /** Returns the value of the <CODE>byte</CODE> property with the specified 
      * name.
      *  
      * @param name the name of the <CODE>byte</CODE> property
      *  
      * @return the <CODE>byte</CODE> property value for the specified name
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid. 
      */ 

    byte
    getByteProperty(String name) throws JMSException;


    /** Returns the value of the <CODE>short</CODE> property with the specified 
      * name.
      *
      * @param name the name of the <CODE>short</CODE> property
      *
      * @return the <CODE>short</CODE> property value for the specified name
      *
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid.
      */
   
    short
    getShortProperty(String name) throws JMSException;
 
 
    /** Returns the value of the <CODE>int</CODE> property with the specified 
      * name.
      *  
      * @param name the name of the <CODE>int</CODE> property
      *  
      * @return the <CODE>int</CODE> property value for the specified name
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid.
      */ 

    int
    getIntProperty(String name) throws JMSException;


    /** Returns the value of the <CODE>long</CODE> property with the specified 
      * name.
      *  
      * @param name the name of the <CODE>long</CODE> property
      *  
      * @return the <CODE>long</CODE> property value for the specified name
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid.
      */ 

    long
    getLongProperty(String name) throws JMSException;


    /** Returns the value of the <CODE>float</CODE> property with the specified 
      * name.
      *  
      * @param name the name of the <CODE>float</CODE> property
      *  
      * @return the <CODE>float</CODE> property value for the specified name
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid.
      */ 

    float
    getFloatProperty(String name) throws JMSException;


    /** Returns the value of the <CODE>double</CODE> property with the specified
      * name.
      *  
      * @param name the name of the <CODE>double</CODE> property
      *  
      * @return the <CODE>double</CODE> property value for the specified name
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid.
      */ 

    double
    getDoubleProperty(String name) throws JMSException;


    /** Returns the value of the <CODE>String</CODE> property with the specified
      * name.
      *  
      * @param name the name of the <CODE>String</CODE> property
      *  
      * @return the <CODE>String</CODE> property value for the specified name;
      * if there is no property by this name, a null value is returned
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      * @exception MessageFormatException if this type conversion is invalid.
      */ 

    String
    getStringProperty(String name) throws JMSException;


    /** Returns the value of the Java object property with the specified name.
      *  
      * <P>This method can be used to return, in objectified format,
      * an object that has been stored as a property in the message with the 
      * equivalent <CODE>setObjectProperty</CODE> method call, or its equivalent
      * primitive <CODE>set<I>type</I>Property</CODE> method.
      *  
      * @param name the name of the Java object property
      *  
      * @return the Java object property value with the specified name, in 
      * objectified format (for example, if the property was set as an 
      * <CODE>int</CODE>, an <CODE>Integer</CODE> is 
      * returned); if there is no property by this name, a null value 
      * is returned
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                         value due to some internal error.
      */ 

    Object
    getObjectProperty(String name) throws JMSException;


    /** Returns an <CODE>Enumeration</CODE> of all the property names.
      *
      * <P>Note that JMS standard header fields are not considered
      * properties and are not returned in this enumeration.
      *  
      * @return an enumeration of all the names of property values
      *  
      * @exception JMSException if the JMS provider fails to get the property
      *                          names due to some internal error.
      */ 
     
    Enumeration
    getPropertyNames() throws JMSException;


    /** Sets a <CODE>boolean</CODE> property value with the specified name into 
      * the message.
      *
      * @param name the name of the <CODE>boolean</CODE> property
      * @param value the <CODE>boolean</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setBooleanProperty(String name, boolean value)
                        throws JMSException;


    /** Sets a <CODE>byte</CODE> property value with the specified name into 
      * the message.
      *  
      * @param name the name of the <CODE>byte</CODE> property
      * @param value the <CODE>byte</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setByteProperty(String name, byte value)
                        throws JMSException;


    /** Sets a <CODE>short</CODE> property value with the specified name into
      * the message.
      *  
      * @param name the name of the <CODE>short</CODE> property
      * @param value the <CODE>short</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setShortProperty(String name, short value)
                        throws JMSException;


    /** Sets an <CODE>int</CODE> property value with the specified name into
      * the message.
      *  
      * @param name the name of the <CODE>int</CODE> property
      * @param value the <CODE>int</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setIntProperty(String name, int value)
                        throws JMSException;


    /** Sets a <CODE>long</CODE> property value with the specified name into 
      * the message.
      *  
      * @param name the name of the <CODE>long</CODE> property
      * @param value the <CODE>long</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setLongProperty(String name, long value)
                        throws JMSException;


    /** Sets a <CODE>float</CODE> property value with the specified name into 
      * the message.
      *  
      * @param name the name of the <CODE>float</CODE> property
      * @param value the <CODE>float</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setFloatProperty(String name, float value)
                        throws JMSException;


    /** Sets a <CODE>double</CODE> property value with the specified name into 
      * the message.
      *  
      * @param name the name of the <CODE>double</CODE> property
      * @param value the <CODE>double</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setDoubleProperty(String name, double value)
                        throws JMSException;


    /** Sets a <CODE>String</CODE> property value with the specified name into 
      * the message.
      *
      * @param name the name of the <CODE>String</CODE> property
      * @param value the <CODE>String</CODE> property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setStringProperty(String name, String value)
                        throws JMSException;


    /** Sets a Java object property value with the specified name into the 
      * message.
      *  
      * <P>Note that this method works only for the objectified primitive
      * object types (<CODE>Integer</CODE>, <CODE>Double</CODE>, 
      * <CODE>Long</CODE> ...) and <CODE>String</CODE> objects.
      *  
      * @param name the name of the Java object property
      * @param value the Java object property value to set
      *  
      * @exception JMSException if the JMS provider fails to set the property
      *                          due to some internal error.
      * @exception MessageFormatException if the object is invalid
      * @exception MessageNotWriteableException if properties are read-only
      */ 

    void
    setObjectProperty(String name, Object value)
                        throws JMSException;


    /** Acknowledges all consumed messages of the session of this consumed 
      * message.
      *  
      * <P>All consumed JMS messages support the <CODE>acknowledge</CODE> 
      * method for use when a client has specified that its JMS session's 
      * consumed messages are to be explicitly acknowledged.  By invoking 
      * <CODE>acknowledge</CODE> on a consumed message, a client acknowledges 
      * all messages consumed by the session that the message was delivered to.
      * 
      * <P>Calls to <CODE>acknowledge</CODE> are ignored for both transacted 
      * sessions and sessions specified to use implicit acknowledgement modes.
      *
      * <P>A client may individually acknowledge each message as it is consumed,
      * or it may choose to acknowledge messages as an application-defined group 
      * (which is done by calling acknowledge on the last received message of the group,
      *  thereby acknowledging all messages consumed by the session.)
      *
      * <P>Messages that have been received but not acknowledged may be 
      * redelivered.
      *
      * @exception JMSException if the JMS provider fails to acknowledge the
      *                         messages due to some internal error.
      * @exception IllegalStateException if this method is called on a closed
      *                         session.
      *
      * @see javax.jms.Session#CLIENT_ACKNOWLEDGE
      */ 

    void
    acknowledge() throws JMSException;


    /** Clears out the message body. Clearing a message's body does not clear 
      * its header values or property entries.
      *
      * <P>If this message body was read-only, calling this method leaves
      * the message body in the same state as an empty body in a newly
      * created message.
      *
      * @exception JMSException if the JMS provider fails to clear the message
      *                         body due to some internal error.
      */

    void
    clearBody() throws JMSException;
}