- /*
- * Copyright 1999-2004 The Apache Software Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- // $Id: XPathExpressionImpl.java,v 1.8 2004/07/10 21:39:19 rameshm Exp $
-
- package com.sun.org.apache.xpath.internal.jaxp;
-
- import com.sun.org.apache.xpath.internal.*;
- import javax.xml.transform.TransformerException;
-
- import com.sun.org.apache.xpath.internal.objects.XObject;
- import com.sun.org.apache.xml.internal.utils.PrefixResolver;
- import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
- import com.sun.org.apache.xalan.internal.res.XSLMessages;
-
- import javax.xml.namespace.NamespaceContext;
- import javax.xml.namespace.QName;
- import javax.xml.xpath.XPathExpressionException;
- import javax.xml.xpath.XPathConstants;
- import javax.xml.xpath.XPathFunctionResolver;
- import javax.xml.xpath.XPathVariableResolver;
- import javax.xml.xpath.XPathConstants;
-
- import org.w3c.dom.Node;
- import org.w3c.dom.Document;
- import org.w3c.dom.DOMImplementation;
- import org.w3c.dom.traversal.NodeIterator;
- import javax.xml.parsers.DocumentBuilderFactory;
- import javax.xml.parsers.DocumentBuilder;
-
- import org.xml.sax.InputSource;
-
- /**
- * The XPathExpression interface encapsulates a (compiled) XPath expression.
- *
- * @version $Revision: 1.8 $
- * @author Ramesh Mandava
- */
- public class XPathExpressionImpl implements javax.xml.xpath.XPathExpression{
-
- private XPathFunctionResolver functionResolver;
- private XPathVariableResolver variableResolver;
- private JAXPPrefixResolver prefixResolver;
- private com.sun.org.apache.xpath.internal.XPath xpath;
-
- // By default Extension Functions are allowed in XPath Expressions. If
- // Secure Processing Feature is set on XPathFactory then the invocation of
- // extensions function need to throw XPathFunctionException
- private boolean featureSecureProcessing = false;
-
- /** Protected constructor to prevent direct instantiation; use compile()
- * from the context.
- */
- protected XPathExpressionImpl() { };
-
- protected XPathExpressionImpl(com.sun.org.apache.xpath.internal.XPath xpath,
- JAXPPrefixResolver prefixResolver,
- XPathFunctionResolver functionResolver,
- XPathVariableResolver variableResolver ) {
- this.xpath = xpath;
- this.prefixResolver = prefixResolver;
- this.functionResolver = functionResolver;
- this.variableResolver = variableResolver;
- this.featureSecureProcessing = false;
- };
-
- protected XPathExpressionImpl(com.sun.org.apache.xpath.internal.XPath xpath,
- JAXPPrefixResolver prefixResolver,
- XPathFunctionResolver functionResolver,
- XPathVariableResolver variableResolver,
- boolean featureSecureProcessing ) {
- this.xpath = xpath;
- this.prefixResolver = prefixResolver;
- this.functionResolver = functionResolver;
- this.variableResolver = variableResolver;
- this.featureSecureProcessing = featureSecureProcessing;
- };
-
- public void setXPath (com.sun.org.apache.xpath.internal.XPath xpath ) {
- this.xpath = xpath;
- }
-
- public Object eval(Object item, QName returnType)
- throws javax.xml.transform.TransformerException {
- XObject resultObject = eval ( item );
- return getResultAsType( resultObject, returnType );
- }
-
- private XObject eval ( Object contextItem )
- throws javax.xml.transform.TransformerException {
- com.sun.org.apache.xpath.internal.XPathContext xpathSupport = null;
- if ( functionResolver != null ) {
- JAXPExtensionsProvider jep = new JAXPExtensionsProvider(
- functionResolver, featureSecureProcessing );
- xpathSupport = new com.sun.org.apache.xpath.internal.XPathContext( jep );
- } else {
- xpathSupport = new com.sun.org.apache.xpath.internal.XPathContext();
- }
-
- xpathSupport.setVarStack(new JAXPVariableStack(variableResolver));
- XObject xobj = null;
-
- Node contextNode = (Node)contextItem;
- // We always need to have a ContextNode with Xalan XPath implementation
- // To allow simple expression evaluation like 1+1 we are setting
- // dummy Document as Context Node
- if ( contextNode == null ) {
- contextNode = getDummyDocument();
- }
-
- xobj = xpath.execute(xpathSupport, contextNode, prefixResolver );
- return xobj;
- }
-
-
- /**
- * <p>Evaluate the compiled XPath expression in the specified context and
- * return the result as the specified type.</p>
- *
- * <p>See "Evaluation of XPath Expressions" section of JAXP 1.3 spec
- * for context item evaluation,
- * variable, function and QName resolution and return type conversion.</p>
- *
- * <p>If <code>returnType</code> is not one of the types defined
- * in {@link XPathConstants},
- * then an <code>IllegalArgumentException</code> is thrown.</p>
- *
- * <p>If a <code>null</code> value is provided for
- * <code>item</code>, an empty document will be used for the
- * context.
- * If <code>returnType</code> is <code>null</code>, then a
- * <code>NullPointerException</code> is thrown.</p>
- *
- * @param item The starting context (node or node list, for example).
- * @param returnType The desired return type.
- *
- * @return The <code>Object</code> that is the result of evaluating the
- * expression and converting the result to
- * <code>returnType</code>.
- *
- * @throws XPathExpressionException If the expression cannot be evaluated.
- * @throws IllegalArgumentException If <code>returnType</code> is not one
- * of the types defined in {@link XPathConstants}.
- * @throws NullPointerException If <code>returnType</code> is
- * <code>null</code>.
- */
- public Object evaluate(Object item, QName returnType)
- throws XPathExpressionException {
- //Validating parameters to enforce constraints defined by JAXP spec
- if ( returnType == null ) {
- //Throwing NullPointerException as defined in spec
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"returnType"} );
- throw new NullPointerException( fmsg );
- }
- // Checking if requested returnType is supported. returnType need to be
- // defined in XPathConstants
- if ( !isSupported ( returnType ) ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
- new Object[] { returnType.toString() } );
- throw new IllegalArgumentException ( fmsg );
- }
- try {
- return eval( item, returnType);
- } catch ( java.lang.NullPointerException npe ) {
- // If VariableResolver returns null Or if we get
- // NullPointerException at this stage for some other reason
- // then we have to reurn XPathException
- throw new XPathExpressionException ( npe );
- } catch ( javax.xml.transform.TransformerException te ) {
- Throwable nestedException = te.getException();
- if ( nestedException instanceof javax.xml.xpath.XPathFunctionException ) {
- throw (javax.xml.xpath.XPathFunctionException)nestedException;
- } else {
- // For any other exceptions we need to throw
- // XPathExpressionException ( as per spec )
- throw new XPathExpressionException( te);
- }
- }
-
- }
-
- /**
- * <p>Evaluate the compiled XPath expression in the specified context and
- * return the result as a <code>String</code>.</p>
- *
- * <p>This method calls {@link #evaluate(Object item, QName returnType)}
- * with a <code>returnType</code> of
- * {@link XPathConstants#STRING}.</p>
- *
- * <p>See "Evaluation of XPath Expressions" section of JAXP 1.3 spec
- * for context item evaluation,
- * variable, function and QName resolution and return type conversion.</p>
- *
- * <p>If a <code>null</code> value is provided for
- * <code>item</code>, an empty document will be used for the
- * context.
- *
- * @param item The starting context (node or node list, for example).
- *
- * @return The <code>String</code> that is the result of evaluating the
- * expression and converting the result to a
- * <code>String</code>.
- *
- * @throws XPathExpressionException If the expression cannot be evaluated.
- */
- public String evaluate(Object item)
- throws XPathExpressionException {
- return (String)this.evaluate( item, XPathConstants.STRING );
- }
-
-
-
- static DocumentBuilderFactory dbf = null;
- static DocumentBuilder db = null;
- static Document d = null;
-
- /**
- * <p>Evaluate the compiled XPath expression in the context of the
- * specified <code>InputSource</code> and return the result as the
- * specified type.</p>
- *
- * <p>This method builds a data model for the {@link InputSource} and calls
- * {@link #evaluate(Object item, QName returnType)} on the resulting
- * document object.</p>
- *
- * <p>See "Evaluation of XPath Expressions" section of JAXP 1.3 spec
- * for context item evaluation,
- * variable, function and QName resolution and return type conversion.</p>
- *
- * <p>If <code>returnType</code> is not one of the types defined in
- * {@link XPathConstants},
- * then an <code>IllegalArgumentException</code> is thrown.</p>
- *
- *<p>If <code>source</code> or <code>returnType</code> is <code>null</code>,
- * then a <code>NullPointerException</code> is thrown.</p>
- *
- * @param source The <code>InputSource</code> of the document to evaluate
- * over.
- * @param returnType The desired return type.
- *
- * @return The <code>Object</code> that is the result of evaluating the
- * expression and converting the result to
- * <code>returnType</code>.
- *
- * @throws XPathExpressionException If the expression cannot be evaluated.
- * @throws IllegalArgumentException If <code>returnType</code> is not one
- * of the types defined in {@link XPathConstants}.
- * @throws NullPointerException If <code>source</code> or
- * <code>returnType</code> is <code>null</code>.
- */
- public Object evaluate(InputSource source, QName returnType)
- throws XPathExpressionException {
- if ( ( source == null ) || ( returnType == null ) ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_SOURCE_RETURN_TYPE_CANNOT_BE_NULL,
- null );
- throw new NullPointerException ( fmsg );
- }
- // Checking if requested returnType is supported. returnType need to be
- // defined in XPathConstants
- if ( !isSupported ( returnType ) ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
- new Object[] { returnType.toString() } );
- throw new IllegalArgumentException ( fmsg );
- }
- try {
- if ( dbf == null ) {
- dbf = DocumentBuilderFactory.newInstance();
- dbf.setNamespaceAware( true );
- dbf.setValidating( false );
- }
- db = dbf.newDocumentBuilder();
- Document document = db.parse( source );
- return eval( document, returnType );
- } catch ( Exception e ) {
- throw new XPathExpressionException ( e );
- }
- }
-
- /**
- * <p>Evaluate the compiled XPath expression in the context of the specified <code>InputSource</code> and return the result as a
- * <code>String</code>.</p>
- *
- * <p>This method calls {@link #evaluate(InputSource source, QName returnType)} with a <code>returnType</code> of
- * {@link XPathConstants#STRING}.</p>
- *
- * <p>See "Evaluation of XPath Expressions" section of JAXP 1.3 spec
- * for context item evaluation,
- * variable, function and QName resolution and return type conversion.</p>
- *
- * <p>If <code>source</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p>
- *
- * @param source The <code>InputSource</code> of the document to evaluate over.
- *
- * @return The <code>String</code> that is the result of evaluating the expression and converting the result to a
- * <code>String</code>.
- *
- * @throws XPathExpressionException If the expression cannot be evaluated.
- * @throws NullPointerException If <code>source</code> is <code>null</code>.
- */
- public String evaluate(InputSource source)
- throws XPathExpressionException {
- return (String)this.evaluate( source, XPathConstants.STRING );
- }
-
- private boolean isSupported( QName returnType ) {
- // XPathConstants.STRING
- if ( ( returnType.equals( XPathConstants.STRING ) ) ||
- ( returnType.equals( XPathConstants.NUMBER ) ) ||
- ( returnType.equals( XPathConstants.BOOLEAN ) ) ||
- ( returnType.equals( XPathConstants.NODE ) ) ||
- ( returnType.equals( XPathConstants.NODESET ) ) ) {
-
- return true;
- }
- return false;
- }
-
- private Object getResultAsType( XObject resultObject, QName returnType )
- throws javax.xml.transform.TransformerException {
- // XPathConstants.STRING
- if ( returnType.equals( XPathConstants.STRING ) ) {
- return resultObject.str();
- }
- // XPathConstants.NUMBER
- if ( returnType.equals( XPathConstants.NUMBER ) ) {
- return new Double ( resultObject.num());
- }
- // XPathConstants.BOOLEAN
- if ( returnType.equals( XPathConstants.BOOLEAN ) ) {
- return new Boolean( resultObject.bool());
- }
- // XPathConstants.NODESET ---ORdered, UNOrdered???
- if ( returnType.equals( XPathConstants.NODESET ) ) {
- return resultObject.nodelist();
- }
- // XPathConstants.NODE
- if ( returnType.equals( XPathConstants.NODE ) ) {
- NodeIterator ni = resultObject.nodeset();
- //Return the first node, or null
- return ni.nextNode();
- }
- // If isSupported check is already done then the execution path
- // shouldn't come here. Being defensive
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
- new Object[] { returnType.toString()});
- throw new IllegalArgumentException ( fmsg );
- }
-
-
- private static Document getDummyDocument( ) {
- try {
- if ( dbf == null ) {
- dbf = DocumentBuilderFactory.newInstance();
- dbf.setNamespaceAware( true );
- dbf.setValidating( false );
- }
- db = dbf.newDocumentBuilder();
-
- DOMImplementation dim = db.getDOMImplementation();
- d = dim.createDocument("http://java.sun.com/jaxp/xpath",
- "dummyroot", null);
- return d;
- } catch ( Exception e ) {
- e.printStackTrace();
- }
- return null;
- }
-
-
-
-
- }