/*
 * @(#)TabularDataSupport.java	3.30 03/12/19
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */


package javax.management.openmbean;


// java import
//
import java.io.IOException;
import java.io.Serializable;
import java.io.ObjectInputStream;
import java.util.Iterator;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Collection;
import java.util.Collections;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.List;

// jmx import
//


/**
 * The <tt>TabularDataSupport</tt> class is the <i>open data</i> class which implements the <tt>TabularData</tt> 
 * and the <tt>Map</tt> interfaces, and which is internally based on a hash map data structure.
 *
 * @version     3.30  03/12/19
 * @author      Sun Microsystems, Inc.
 *
 * @since 1.5
 * @since.unbundled JMX 1.1
 */
public class TabularDataSupport 
    implements TabularData, Map, Cloneable, Serializable { 
    
    
    /* Serial version */
    static final long serialVersionUID = 5720150593236309827L;


    /**
     * @serial This tabular data instance's contents: a {@link HashMap}
     */
    private Map 	dataMap;
    
    /**
     * @serial This tabular data instance's tabular type
     */
    private TabularType tabularType;

    /**
     * @serial The array of item names that define the index used for rows (convenience field)
     */
    private transient String[] indexNamesArray;
    


    /* *** Constructors *** */


    /**
     * Creates an empty <tt>TabularDataSupport</tt> instance whose open-type is <var>tabularType</var>, 
     * and whose underlying <tt>HashMap</tt> has a default initial capacity (101) and default load factor (0.75).
     * <p>
     * This constructor simply calls <tt>this(tabularType, 101, 0.75f);</tt>
     *
     * @param  tabularType 		 the <i>tabular type</i> describing this <tt>TabularData</tt> instance;
     *					 cannot be null.
     *
     * @throws IllegalArgumentException  if the tabular type is null. 
     */
    public TabularDataSupport(TabularType tabularType) {

	this(tabularType, 101, 0.75f);
    }

    /**
     * Creates an empty <tt>TabularDataSupport</tt> instance whose open-type is <var>tabularType</var>, 
     * and whose underlying <tt>HashMap</tt> has the specified initial capacity and load factor.
     *
     * @param  tabularType		 the <i>tabular type</i> describing this <tt>TabularData</tt> instance;
     *				 cannot be null.
     *
     * @param  initialCapacity   the initial capacity of the HashMap.
     * 
     * @param  loadFactor        the load factor of the HashMap
     * 
     * @throws IllegalArgumentException  if the initial capacity is less than zero, 
     *					 or the load factor is nonpositive,
     *					 or the tabular type is null.
     */
    public TabularDataSupport(TabularType tabularType, int initialCapacity, float loadFactor) {

	// Check tabularType is not null
	//
	if (tabularType == null) {
	    throw new IllegalArgumentException("Argument tabularType cannot be null.");
	}

	// Initialize this.tabularType (and indexNamesArray for convenience)
	//
	this.tabularType = tabularType;
	List tmpNames = tabularType.getIndexNames();
	this.indexNamesArray = (String[]) tmpNames.toArray(new String[tmpNames.size()]);
	
	// Construct the empty contents HashMap
	//
	this.dataMap = new HashMap(initialCapacity, loadFactor);
    }




    /* *** TabularData specific information methods *** */


    /**
     * Returns the <i>tabular type</i> describing this <tt>TabularData</tt> instance.
     */
    public TabularType getTabularType() {

	return tabularType;
    }

    /**
     * Calculates the index that would be used in this <tt>TabularData</tt> instance to refer to the specified
     * composite data <var>value</var> parameter if it were added to this instance.
     * This method checks for the type validity of the specified <var>value</var>, 
     * but does not check if the calculated index is already used to refer to a value in this <tt>TabularData</tt> instance.
     *
     * @param  value			  the composite data value whose index in this 
     *					  <tt>TabularData</tt> instance is to be calculated;
     *					  must be of the same composite type as this instance's row type;
     *					  must not be null.
     *
     * @return the index that the specified <var>value</var> would have in this <tt>TabularData</tt> instance.
     * 
     * @throws NullPointerException       if <var>value</var> is <tt>null</tt>. 
     * 
     * @throws InvalidOpenTypeException   if <var>value</var> does not conform to this <tt>TabularData</tt> instance's 
     *				          row type definition.
     */
    public Object[] calculateIndex(CompositeData value) {

	// Check value is valid
	//
	checkValueType(value);

	// Return its calculated index
	//
	return internalCalculateIndex(value).toArray();
    }




    /* *** Content information query methods *** */


    /**
     * Returns <tt>true</tt> if and only if this <tt>TabularData</tt> instance contains a <tt>CompositeData</tt> value 
     * (ie a row) whose index is the specified <var>key</var>. If <var>key</var> cannot be cast to a one dimension array
     * of Object instances, this method simply returns <tt>false</tt> otherwise it returns the the result of the call to
     * <tt>this.containsKey((Object[]) key)</tt>.
     * 
     * @param  key  the index value whose presence in this <tt>TabularData</tt> instance is to be tested.
     *
     * @return  <tt>true</tt> if this <tt>TabularData</tt> indexes a row value with the specified key.
     */ 
    public boolean containsKey(Object key) { 

	// if key is not an array of Object instances, return false
	//
	Object[] k;
	try {
	    k = (Object[]) key;
	} catch (ClassCastException e) {
	    return false;
	}

	return  this.containsKey(k);
    }

    /**
     * Returns <tt>true</tt> if and only if this <tt>TabularData</tt> instance contains a <tt>CompositeData</tt> value 
     * (ie a row) whose index is the specified <var>key</var>. If <var>key</var> is <tt>null</tt> or does not conform to
     * this <tt>TabularData</tt> instance's <tt>TabularType</tt> definition, this method simply returns <tt>false</tt>.
     * 
     * @param  key  the index value whose presence in this <tt>TabularData</tt> instance is to be tested.
     *
     * @return  <tt>true</tt> if this <tt>TabularData</tt> indexes a row value with the specified key.
     */ 
    public boolean containsKey(Object[] key) { 

	return  ( key == null ?  false :  dataMap.containsKey(Arrays.asList(key)) );
    }

    /**
     * Returns <tt>true</tt> if and only if this <tt>TabularData</tt> instance contains the specified
     * <tt>CompositeData</tt> value. If <var>value</var> is <tt>null</tt> or does not conform to
     * this <tt>TabularData</tt> instance's row type definition, this method simply returns <tt>false</tt>.
     *
     * @param  value  the row value whose presence in this <tt>TabularData</tt> instance is to be tested.
     *
     * @return  <tt>true</tt> if this <tt>TabularData</tt> instance contains the specified row value.
     */
    public boolean containsValue(CompositeData value) { 

	return dataMap.containsValue(value);
    }

    /**
     * Returns <tt>true</tt> if and only if this <tt>TabularData</tt> instance contains the specified
     * value.
     *
     * @param  value  the row value whose presence in this <tt>TabularData</tt> instance is to be tested.
     *
     * @return  <tt>true</tt> if this <tt>TabularData</tt> instance contains the specified row value.
     */
    public boolean containsValue(Object value) { 

	return dataMap.containsValue(value);
    }

    /**
     * This method simply calls <tt>get((Object[]) key)</tt>.
     *
     * @throws NullPointerException  if the <var>key</var> is <tt>null</tt> 
     * @throws ClassCastException    if the <var>key</var> is not of the type <tt>Object[]</tt>
     * @throws InvalidKeyException   if the <var>key</var> does not conform to this <tt>TabularData</tt> instance's 
     *				     <tt>TabularType</tt> definition 
     */
    public Object get(Object key) {

	return get((Object[]) key);
    }

    /**
     * Returns the <tt>CompositeData</tt> value whose index is
     * <var>key</var>, or <tt>null</tt> if there is no value mapping
     * to <var>key</var>, in this <tt>TabularData</tt> instance.
     *
     * @param key the index of the value to get in this
     * <tt>TabularData</tt> instance; * must be valid with this
     * <tt>TabularData</tt> instance's row type definition; * must not
     * be null.
     *
     * @return the value corresponding to <var>key</var>.
     * 
     * @throws NullPointerException  if the <var>key</var> is <tt>null</tt> 
     * @throws InvalidKeyException   if the <var>key</var> does not conform to this <tt>TabularData</tt> instance's 
     *				     <tt>TabularType</tt> type definition.
     */
    public CompositeData get(Object[] key) { 

	// Check key is not null and valid with tabularType 
	// (throws NullPointerException, InvalidKeyException)
	//
	checkKeyType(key);

	// Return the mapping stored in the parent HashMap
	//
	return (CompositeData) dataMap.get(Arrays.asList(key));
    }




    /* *** Content modification operations (one element at a time) *** */


    /**
     * This method simply calls <tt>put((CompositeData) value)</tt> and  
     * therefore ignores its <var>key</var> parameter which can be <tt>null</tt>.
     *
     * @param key an ignored parameter.
     * @param value the {@link CompositeData} to put.
     *
     * @return the value which is put
     *
     * @throws NullPointerException  if the <var>value</var> is <tt>null</tt> 
     * @throws ClassCastException    if the <var>value</var> is not of the type <tt>CompositeData</tt>
     * @throws InvalidOpenTypeException   if the <var>value</var> does not conform to this <tt>TabularData</tt> instance's 
     *				          <tt>TabularType</tt> definition 
     * @throws KeyAlreadyExistsException   if the key for the <var>value</var> parameter, calculated according to 
     *					   this <tt>TabularData</tt> instance's <tt>TabularType</tt> definition 
     *					   already maps to an existing value  
     */
    public Object put(Object key, Object value) {

	put((CompositeData) value);
	return value;
    }

    public void put(CompositeData value) {

	// Check value is not null, value's type is the same as this instance's row type, 
	// and calculate the value's index according to this instance's tabularType and
	// check it is not already used for a mapping in the parent HashMap
	//
	List index = checkValueAndIndex(value);

	// store the (key, value) mapping in the dataMap HashMap
	//
	dataMap.put(index, value);
    }

    /**
     * This method simply calls <tt>remove((Object[]) key)</tt>.
     *
     * @param key an <tt>Object[]</tt> representing the key to remove.
     *
     * @return previous value associated with specified key, or <tt>null</tt>
     *	       if there was no mapping for key.  
     *
     * @throws NullPointerException  if the <var>key</var> is <tt>null</tt> 
     * @throws ClassCastException    if the <var>key</var> is not of the type <tt>Object[]</tt>
     * @throws InvalidKeyException   if the <var>key</var> does not conform to this <tt>TabularData</tt> instance's 
     *				     <tt>TabularType</tt> definition 
     */
    public Object remove(Object key) {

	return remove((Object[]) key);
    }

    /**
     * Removes the <tt>CompositeData</tt> value whose index is <var>key</var> from this <tt>TabularData</tt> instance,
     * and returns the removed value, or returns <tt>null</tt> if there is no value whose index is <var>key</var>.
     *
     * @param  key  the index of the value to get in this <tt>TabularData</tt> instance;
     *		    must be valid with this <tt>TabularData</tt> instance's row type definition;
     *		    must not be null.
     * 
     * @return previous value associated with specified key, or <tt>null</tt>
     *	       if there was no mapping for key.  
     *
     * @throws NullPointerException  if the <var>key</var> is <tt>null</tt> 
     * @throws InvalidKeyException   if the <var>key</var> does not conform to this <tt>TabularData</tt> instance's 
     *				     <tt>TabularType</tt> definition 
     */
    public CompositeData remove(Object[] key) { 

	// Check key is not null and valid with tabularType 
	// (throws NullPointerException, InvalidKeyException)
	//
	checkKeyType(key);

	// Removes the (key, value) mapping in the parent HashMap
	//
	return (CompositeData) dataMap.remove(Arrays.asList(key));
    }




    /* ***   Content modification bulk operations   *** */


    /**
     * Add all the values contained in the specified map <var>t</var> to this <tt>TabularData</tt> instance. 
     * This method converts the collection of values contained in this map into an array of <tt>CompositeData</tt> values,
     * if possible, and then call the method <tt>putAll(CompositeData[])</tt>. Note that the keys used in the specified
     * map <var>t</var> are ignored. This method allows, for example to add the content of another <tt>TabularData</tt> 
     * instance with the same row type (but possibly different index names) into this instance.
     *
     * @param  t  the map whose values are to be added as new rows to this <tt>TabularData</tt> instance;
     *		  if <var>t</var> is <tt>null</tt> or empty, this method returns without doing anything.
     * 
     * @throws NullPointerException  if a value in <var>t</var> is <tt>null</tt>.
     * @throws ClassCastException    if a value in <var>t</var> is not an instance of <tt>CompositeData</tt>.
     * @throws InvalidOpenTypeException   if a value in <var>t</var> does not conform to 
     *					  this <tt>TabularData</tt> instance's row type definition.
     * @throws KeyAlreadyExistsException  if the index for a value in <var>t</var>, calculated according to 
     *					  this <tt>TabularData</tt> instance's <tt>TabularType</tt> definition 
     *					  already maps to an existing value in this instance,
     *					  or two values in <var>t</var> have the same index.
     */
    public void putAll(Map t) {

	// if t is null or empty, just return
	//
	if ( (t == null) || (t.size() == 0) ) {
	    return;
	}

	// Convert the values in t into an array of <tt>CompositeData</tt>
	//
	CompositeData[] values;
	try {
	    values = (CompositeData[]) t.values().toArray(new CompositeData[t.size()]);
	} catch (java.lang.ArrayStoreException e) {
	    throw new ClassCastException("Map argument t contains values which are not instances of <tt>CompositeData</tt>");
	}
	
	// Add the array of values
	//
	putAll(values);
    }

    /**
     * Add all the elements in <var>values</var> to this <tt>TabularData</tt> instance. 
     * If any  element in <var>values</var> does not satisfy the constraints defined in {@link #put(CompositeData) <tt>put</tt>},
     * or if any two elements in <var>values</var> have the same index calculated according to this <tt>TabularData</tt> 
     * instance's <tt>TabularType</tt> definition, then an exception describing the failure is thrown 
     * and no element of <var>values</var> is added,  thus leaving this <tt>TabularData</tt> instance unchanged.
     *
     * @param  values  the array of composite data values to be added as new rows to this <tt>TabularData</tt> instance;
     *		       if <var>values</var> is <tt>null</tt> or empty, this method returns without doing anything.
     * 
     * @throws NullPointerException       if an element of <var>values</var> is <tt>null</tt> 
     * @throws InvalidOpenTypeException   if an element of <var>values</var> does not conform to 
     *					  this <tt>TabularData</tt> instance's row type definition 
     *					  (ie its <tt>TabularType</tt> definition)
     * @throws KeyAlreadyExistsException  if the index for an element of <var>values</var>, calculated according to 
     *					  this <tt>TabularData</tt> instance's <tt>TabularType</tt> definition 
     *					  already maps to an existing value in this instance,
     *					  or two elements of <var>values</var> have the same index
     */
    public void putAll(CompositeData[] values) {

	// if values is null or empty, just return
	//
	if ( (values == null) || (values.length == 0) ) {
	    return;
	}

	// create the list of indexes corresponding to each value
	ArrayList indexes = new ArrayList(values.length + 1);

	// Check all elements in values and build index list 
	//
	List index;
	for (int i=0; i<values.length; i++) {
	    // check value and calculate index
	    index = checkValueAndIndex(values[i]);
	    // check index is different of those previously calculated
	    if (indexes.contains(index)) {
		throw new KeyAlreadyExistsException("Argument elements values["+ i +"] and values["+ indexes.indexOf(index) +
						    "] have the same indexes, "+
						    "calculated according to this TabularData instance's tabularType.");
	    }
	    // add to index list
	    indexes.add(index);
	}

	// store all (index, value) mappings in the dataMap HashMap
	//
	for (int i=0; i<values.length; i++) {
	    dataMap.put(indexes.get(i), values[i]);
	}
    }

    /**
     * Removes all rows from this <code>TabularDataSupport</code> instance.
     */
    public void clear() {

        dataMap.clear();
    }



    /* ***  Informational methods from java.util.Map  *** */
    
    /**
     * Returns the number of rows in this <code>TabularDataSupport</code> instance.
     *
     * @return the number of rows in this <code>TabularDataSupport</code> instance.
     */
    public int size() {
    
	return dataMap.size();
    }

    /**
     * Returns <tt>true</tt> if this <code>TabularDataSupport</code> instance contains no rows.
     *
     * @return <tt>true</tt> if this <code>TabularDataSupport</code> instance contains no rows.
     */
    public boolean isEmpty() {
    
	return (this.size() == 0);
    }
    


    /* ***  Collection views from java.util.Map  *** */
    
    /**
     * Returns a set view of the keys contained in the underlying map of this <code>TabularDataSupport</code> instance,
     * and used to index the rows. Each key contained in this set is an unmodifiable List.  
     * The set is backed by the underlying map of this <code>TabularDataSupport</code> instance, 
     * so changes to the <code>TabularDataSupport</code> instance are reflected in the set, and vice-versa.
     *
     * The set supports element removal, which removes the
     * corresponding row from this <code>TabularDataSupport</code> instance, via the <tt>Iterator.remove</tt>,
     * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
     * <tt>clear</tt> operations.  
     * It does not support the <tt>add</tt> or <tt>addAll</tt> operations
     *
     * @return a set view of the keys used to index the rows of this <code>TabularDataSupport</code> instance.
     */
    public Set keySet() {
    
        return  dataMap.keySet() ;
    }
    
    /**
     * Returns a collection view of the rows contained in this <code>TabularDataSupport</code> instance.  
     * The collection is backed by the underlying map, so changes to the <code>TabularDataSupport</code> instance 
     * are reflected in the collection, and vice-versa.
     *
     * The collection supports element removal, 
     * which removes the corresponding index to row mapping from this <code>TabularDataSupport</code> instance, 
     * via the <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
     * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
     * It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
     *
     * @return a collection view of the values contained in this <code>TabularDataSupport</code> instance.
     */
    public Collection values() {
    
        return  dataMap.values() ;
    }
    
        
    /** 
     * Returns a collection view of the index to row mappings contained in this <code>TabularDataSupport</code> instance.  
     * Each element in the returned collection is a <tt>Map.Entry</tt>.  
     * The collection is backed by the underlying map of this <code>TabularDataSupport</code> instance,  in
     * so changes to the <code>TabularDataSupport</code> instance are reflected the collection, and vice-versa.  
     * The collection supports element removal, which removes the corresponding mapping from the map, via the
     * <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
     * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
     * It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
     * <p>
     * <b>IMPORTANT NOTICE</b>: Do not use the <tt>SetValue</tt> method of <tt>Map.Entry</tt> elements contained in the returned
     * collection view. Doing so would corrupt the index to row mappings contained in this <code>TabularDataSupport</code> instance.
     * <p>
     *
     * @return a collection view of the mappings contained in this map.
     * @see java.util.Map.Entry
     */
    public Set entrySet() {
    
        return  dataMap.entrySet();
    }


    /* ***  Commodity methods from java.lang.Object  *** */


    /**
     * Returns a clone of this <code>TabularDataSupport</code> instance: 
     * the clone is obtained by calling <tt>super.clone()</tt>, and then cloning the underlying map.
     * Only a shallow clone of the underlying map is made, i.e. no cloning of the indexes and row values is made as they are immutable.
     */
    public Object clone() {
	try {
	    TabularDataSupport c = (TabularDataSupport) super.clone();
	    c.dataMap = (HashMap) ((HashMap) c.dataMap).clone();
	    return c;
	}
	catch (CloneNotSupportedException e) {
	    throw new InternalError(e.toString());
	}
    }


    /**
     * Compares the specified <var>obj</var> parameter with this <code>TabularDataSupport</code> instance for equality. 
     * <p>
     * Returns <tt>true</tt> if and only if all of the following statements are true:
     * <ul>
     * <li><var>obj</var> is non null,</li>
     * <li><var>obj</var> also implements the <code>TabularData</code> interface,</li>
     * <li>their tabular types are equal</li>
     * <li>their contents (ie all CompositeData values) are equal.</li>
     * </ul>
     * This ensures that this <tt>equals</tt> method works properly for <var>obj</var> parameters which are
     * different implementations of the <code>TabularData</code> interface.
     * <br> 
     * @param  obj  the object to be compared for equality with this <code>TabularDataSupport</code> instance;
     * 
     * @return  <code>true</code> if the specified object is equal to this <code>TabularDataSupport</code> instance.
     */
    public boolean equals(Object obj) { 

	// if obj is null, return false
	//
	if (obj == null) {
	    return false;
	}

	// if obj is not a TabularData, return false
	//
	TabularData other;
	try {
	    other = (TabularData) obj;
	} catch (ClassCastException e) {
	    return false;
	}

	// Now, really test for equality between this TabularData implementation and the other:
	//
	
	// their tabularType should be equal
	if ( ! this.getTabularType().equals(other.getTabularType()) ) {
	    return false;
	}

	// their contents should be equal: 
	// . same size
	// . values in this instance are in the other (we know there are no duplicate elements possible)
	// (row values comparison is enough, because keys are calculated according to tabularType)
	
	if (this.size() != other.size()) {
	    return false;
	}
	for (Iterator iter = this.values().iterator(); iter.hasNext();  ) {
	    CompositeData value = (CompositeData) iter.next();
	    if ( ! other.containsValue(value) ) {
		return false;
	    }
	}
       
	// All tests for equality were successfull
	//
	return true;
    }

    /**
     * Returns the hash code value for this <code>TabularDataSupport</code> instance. 
     * <p>
     * The hash code of a <code>TabularDataSupport</code> instance is the sum of the hash codes
     * of all elements of information used in <code>equals</code> comparisons 
     * (ie: its <i>tabular type</i> and its content, where the content is defined as all the CompositeData values). 
     * <p>
     * This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code> 
     * for any two <code>TabularDataSupport</code> instances <code>t1</code> and <code>t2</code>, 
     * as required by the general contract of the method
     * {@link Object#hashCode() Object.hashCode()}.
     * <p>
     * However, note that another instance of a class implementing the <code>TabularData</code> interface
     * may be equal to this <code>TabularDataSupport</code> instance as defined by {@link #equals}, 
     * but may have a different hash code if it is calculated differently.
     *
     * @return  the hash code value for this <code>TabularDataSupport</code> instance
     */
   public int hashCode() { 

	int result = 0;

	result += this.tabularType.hashCode();
	for (Iterator iter = this.values().iterator(); iter.hasNext();  ) {
	    result += ((CompositeData)iter.next()).hashCode();
	}

	return result;

    }

    /**
     * Returns a string representation of this <code>TabularDataSupport</code> instance. 
     * <p>
     * The string representation consists of the name of this class (ie <code>javax.management.openmbean.TabularDataSupport</code>), 
     * the string representation of the tabular type of this instance, and the string representation of the contents
     * (ie list the key=value mappings as returned by a call to
     * <tt>dataMap.</tt>{@link java.util.HashMap#toString() toString()}).
     * 
     * @return  a string representation of this <code>TabularDataSupport</code> instance
     */
    public String toString() { 

	return new StringBuffer()
	    .append(this.getClass().getName())
	    .append("(tabularType=")
	    .append(tabularType.toString())
	    .append(",contents=")
	    .append(dataMap.toString())
	    .append(")")
	    .toString();
    }




    /* *** TabularDataSupport internal utility methods *** */


    /**
     * Returns the index for value, assuming value is valid for this <tt>TabularData</tt> instance 
     * (ie value is not null, and its composite type is equal to row type).
     * 
     * The index is a List, and not an array, so that an index.equals(otherIndex) call will actually compare contents,
     * not just the objects references as is done for an array object.
     *
     * The returned List is unmodifiable so that once a row has been put into the dataMap, its index cannot be modified,
     * for example by a user that would attempt to modify an index contained in the Set returned by keySet(). 
     */
    private List internalCalculateIndex(CompositeData value) {

	return Collections.unmodifiableList(Arrays.asList(value.getAll(this.indexNamesArray)));
    }

    /**
     * Checks if the specified key is valid for this <tt>TabularData</tt> instance.
     *
     * @throws  NullPointerException
     * @throws  InvalidOpenTypeException
     */
    private void checkKeyType(Object[] key) { 
	
	// Check key is neither null nor empty
	//
	if ( (key == null) || (key.length == 0) ) {
	    throw new NullPointerException("Argument key cannot be null or empty.");
	}

	/* Now check key is valid with tabularType index and row type definitions: */

	// key[] should have the size expected for an index 
	//
	if (key.length != this.indexNamesArray.length) {
	    throw new InvalidKeyException("Argument key's length="+ key.length +
					  " is different from the number of item values, which is "+ indexNamesArray.length +
					  ", specified for the indexing rows in this TabularData instance.");
	}

	// each element in key[] should be a value for its corresponding open type specified in rowType
	//
	OpenType keyElementType;
	for (int i=0; i<key.length; i++) {
	    keyElementType = tabularType.getRowType().getType(this.indexNamesArray[i]);
	    if ( (key[i] != null) && (! keyElementType.isValue(key[i])) ) {
		throw new InvalidKeyException("Argument element key["+ i +"] is not a value for the open type expected for "+
					      "this element of the index, whose name is \""+ indexNamesArray[i] +
					      "\" and whose open type is "+ keyElementType);
	    }
	}
    }

    /**
     * Checks the specified value's type is valid for this <tt>TabularData</tt> instance 
     * (ie value is not null, and its composite type is equal to row type).
     *
     * @throws  NullPointerException
     * @throws  InvalidOpenTypeException
     */
    private void checkValueType(CompositeData value) {

	// Check value is not null
	//
	if (value == null) {
	    throw new NullPointerException("Argument value cannot be null.");
	}
	
	// if value's type is not the same as this instance's row type, throw InvalidOpenTypeException
	//
	if ( ! value.getCompositeType().equals(tabularType.getRowType()) ) {
	    throw new InvalidOpenTypeException("Argument value's composite type ["+ value.getCompositeType() +
					       "] is not equal to "+
					       "this TabularData instance's row type ["+ tabularType.getRowType() +"].");
	}
    }

    /**
     * Checks if the specified value can be put (ie added) in this <tt>TabularData</tt> instance
     * (ie value is not null, its composite type is equal to row type, and its index is not already used),
     * and returns the index calculated for this value. 
     * 
     * The index is a List, and not an array, so that an index.equals(otherIndex) call will actually compare contents,
     * not just the objects references as is done for an array object.
     *
     * @throws  NullPointerException
     * @throws  InvalidOpenTypeException
     * @throws  KeyAlreadyExistsException
     */
    private List checkValueAndIndex(CompositeData value) {

	// Check value is valid
	//
	checkValueType(value);

	// Calculate value's index according to this instance's tabularType
	// and check it is not already used for a mapping in the parent HashMap
	//
	List index = internalCalculateIndex(value);
	
	if (dataMap.containsKey(index)) {
	    throw new KeyAlreadyExistsException("Argument value's index, calculated according to this TabularData "+
						"instance's tabularType, already refers to a value in this table.");
	}
	
	// The check is OK, so return the index
	//
	return index;
    }

    /**
     * Deserializes a {@link TabularDataSupport} from an {@link ObjectInputStream}.
     */
    private void readObject(ObjectInputStream in)
	    throws IOException, ClassNotFoundException {
      in.defaultReadObject();
      List tmpNames = tabularType.getIndexNames();
      indexNamesArray = (String[]) tmpNames.toArray(new String[tmpNames.size()]);
    }
}