- /*
- * 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: XPathImpl.java,v 1.15 2004/07/10 21:39:19 rameshm Exp $
-
- package com.sun.org.apache.xpath.internal.jaxp;
-
- import javax.xml.namespace.QName;
- import javax.xml.namespace.NamespaceContext;
- import javax.xml.xpath.XPathExpressionException;
- import javax.xml.xpath.XPathConstants;
- import javax.xml.xpath.XPathFunctionResolver;
- import javax.xml.xpath.XPathVariableResolver;
- import javax.xml.xpath.XPathExpression;
-
- import com.sun.org.apache.xml.internal.dtm.DTM;
- import com.sun.org.apache.xpath.internal.*;
- import com.sun.org.apache.xpath.internal.objects.XObject;
- import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
- import com.sun.org.apache.xalan.internal.res.XSLMessages;
-
- import org.w3c.dom.Node;
- import org.w3c.dom.DOMImplementation;
- import org.w3c.dom.Document;
- import org.w3c.dom.traversal.NodeIterator;
-
- import org.xml.sax.InputSource;
- import org.xml.sax.SAXException;
-
- import javax.xml.parsers.*;
-
- import java.io.IOException;
-
- /**
- * The XPathImpl class provides implementation for the methods defined in
- * javax.xml.xpath.XPath interface. This provide simple access to the results
- * of an XPath expression.
- *
- *
- * @version $Revision: 1.15 $
- * @author Ramesh Mandava
- */
- public class XPathImpl implements javax.xml.xpath.XPath {
-
- // Private variables
- private XPathVariableResolver variableResolver;
- private XPathFunctionResolver functionResolver;
- private XPathVariableResolver origVariableResolver;
- private XPathFunctionResolver origFunctionResolver;
- private NamespaceContext namespaceContext=null;
- private JAXPPrefixResolver prefixResolver;
- // 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;
-
- XPathImpl( XPathVariableResolver vr, XPathFunctionResolver fr ) {
- this.origVariableResolver = this.variableResolver = vr;
- this.origFunctionResolver = this.functionResolver = fr;
- }
-
- XPathImpl( XPathVariableResolver vr, XPathFunctionResolver fr,
- boolean featureSecureProcessing ) {
- this.origVariableResolver = this.variableResolver = vr;
- this.origFunctionResolver = this.functionResolver = fr;
- this.featureSecureProcessing = featureSecureProcessing;
- }
-
- /**
- * <p>Establishes a variable resolver.</p>
- *
- * @param resolver Variable Resolver
- */
- public void setXPathVariableResolver(XPathVariableResolver resolver) {
- if ( resolver == null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"XPathVariableResolver"} );
- throw new NullPointerException( fmsg );
- }
- this.variableResolver = resolver;
- }
-
- /**
- * <p>Returns the current variable resolver.</p>
- *
- * @return Current variable resolver
- */
- public XPathVariableResolver getXPathVariableResolver() {
- return variableResolver;
- }
-
- /**
- * <p>Establishes a function resolver.</p>
- *
- * @param resolver XPath function resolver
- */
- public void setXPathFunctionResolver(XPathFunctionResolver resolver) {
- if ( resolver == null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"XPathFunctionResolver"} );
- throw new NullPointerException( fmsg );
- }
- this.functionResolver = resolver;
- }
-
- /**
- * <p>Returns the current function resolver.</p>
- *
- * @return Current function resolver
- */
- public XPathFunctionResolver getXPathFunctionResolver() {
- return functionResolver;
- }
-
- /**
- * <p>Establishes a namespace context.</p>
- *
- * @param nsContext Namespace context to use
- */
- public void setNamespaceContext(NamespaceContext nsContext) {
- if ( nsContext == null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"NamespaceContext"} );
- throw new NullPointerException( fmsg );
- }
- this.namespaceContext = nsContext;
- this.prefixResolver = new JAXPPrefixResolver ( nsContext );
- }
-
- /**
- * <p>Returns the current namespace context.</p>
- *
- * @return Current Namespace context
- */
- public NamespaceContext getNamespaceContext() {
- return namespaceContext;
- }
-
- private static Document d = null;
-
- private static DocumentBuilder getParser() {
- try {
- // we'd really like to cache those DocumentBuilders, but we can't because:
- // 1. thread safety. parsers are not thread-safe, so at least
- // we need one instance per a thread.
- // 2. parsers are non-reentrant, so now we are looking at having a
- // pool of parsers.
- // 3. then the class loading issue. The look-up procedure of
- // DocumentBuilderFactory.newInstance() depends on context class loader
- // and system properties, which may change during the execution of JVM.
- //
- // so we really have to create a fresh DocumentBuilder every time we need one
- // - KK
- DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
- dbf.setNamespaceAware( true );
- dbf.setValidating( false );
- return dbf.newDocumentBuilder();
- } catch (ParserConfigurationException e) {
- // this should never happen with a well-behaving JAXP implementation.
- throw new Error(e);
- }
- }
-
- private static Document getDummyDocument( ) {
- // we don't need synchronization here; even if two threads
- // enter this code at the same time, we just waste a little time
- if(d==null) {
- DOMImplementation dim = getParser().getDOMImplementation();
- d = dim.createDocument("http://java.sun.com/jaxp/xpath",
- "dummyroot", null);
- }
- return d;
- }
-
-
- private XObject eval(String expression, Object contextItem)
- throws javax.xml.transform.TransformerException {
- com.sun.org.apache.xpath.internal.XPath xpath = new com.sun.org.apache.xpath.internal.XPath( expression,
- null, prefixResolver, com.sun.org.apache.xpath.internal.XPath.SELECT );
- 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();
- }
-
- XObject xobj = null;
-
- xpathSupport.setVarStack(new JAXPVariableStack(variableResolver));
-
- // If item is null, then we will create a a Dummy contextNode
- if ( contextItem instanceof Node ) {
- xobj = xpath.execute (xpathSupport, (Node)contextItem,
- prefixResolver );
- } else {
- xobj = xpath.execute ( xpathSupport, DTM.NULL, prefixResolver );
- }
-
- return xobj;
- }
-
- /**
- * <p>Evaluate an <code>XPath</code> 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 <code>QName</code> resolution and return type conversion.</p>
- *
- * <p>If <code>returnType</code> is not one of the types defined in {@link XPathConstants} (
- * {@link XPathConstants#NUMBER NUMBER},
- * {@link XPathConstants#STRING STRING},
- * {@link XPathConstants#BOOLEAN BOOLEAN},
- * {@link XPathConstants#NODE NODE} or
- * {@link XPathConstants#NODESET NODESET})
- * 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>expression</code> or <code>returnType</code> is <code>null</code>, then a
- * <code>NullPointerException</code> is thrown.</p>
- *
- * @param expression The XPath expression.
- * @param item The starting context (node or node list, for example).
- * @param returnType The desired return type.
- *
- * @return Result of evaluating an XPath expression as an <code>Object</code> of <code>returnType</code>.
- *
- * @throws XPathExpressionException If <code>expression</code> cannot be evaluated.
- * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}.
- * @throws NullPointerException If <code>expression</code> or <code>returnType</code> is <code>null</code>.
- */
- public Object evaluate(String expression, Object item, QName returnType)
- throws XPathExpressionException {
- if ( expression == null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"XPath expression"} );
- throw new NullPointerException ( fmsg );
- }
- if ( returnType == null ) {
- 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 {
-
- XObject resultObject = eval( expression, item );
- return getResultAsType( resultObject, 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 );
- }
- }
-
- }
-
- private boolean isSupported( QName returnType ) {
- 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();
- }
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
- new Object[] { returnType.toString()});
- throw new IllegalArgumentException( fmsg );
- }
-
-
-
- /**
- * <p>Evaluate an XPath expression in the specified context and return the result as a <code>String</code>.</p>
- *
- * <p>This method calls {@link #evaluate(String expression, Object item, QName returnType)} with a <code>returnType</code> of
- * {@link XPathConstants#STRING}.</p>
- *
- * <p>See "Evaluation of XPath Expressions" 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.
- * If <code>expression</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p>
- *
- * @param expression The XPath expression.
- * @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 <code>expression</code> cannot be evaluated.
- * @throws NullPointerException If <code>expression</code> is <code>null</code>.
- */
- public String evaluate(String expression, Object item)
- throws XPathExpressionException {
- return (String)this.evaluate( expression, item, XPathConstants.STRING );
- }
-
- /**
- * <p>Compile an XPath expression for later evaluation.</p>
- *
- * <p>If <code>expression</code> contains any {@link XPathFunction}s,
- * they must be available via the {@link XPathFunctionResolver}.
- * An {@link XPathExpressionException} will be thrown if the <code>XPathFunction</code>
- * cannot be resovled with the <code>XPathFunctionResolver</code>.</p>
- *
- * <p>If <code>expression</code> is <code>null</code>, a <code>NullPointerException</code> is thrown.</p>
- *
- * @param expression The XPath expression.
- *
- * @return Compiled XPath expression.
-
- * @throws XPathExpressionException If <code>expression</code> cannot be compiled.
- * @throws NullPointerException If <code>expression</code> is <code>null</code>.
- */
- public XPathExpression compile(String expression)
- throws XPathExpressionException {
- if ( expression == null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"XPath expression"} );
- throw new NullPointerException ( fmsg );
- }
- try {
- com.sun.org.apache.xpath.internal.XPath xpath = new XPath (expression, null,
- prefixResolver, com.sun.org.apache.xpath.internal.XPath.SELECT );
- // Can have errorListener
- XPathExpressionImpl ximpl = new XPathExpressionImpl (xpath,
- prefixResolver, functionResolver, variableResolver,
- featureSecureProcessing );
- return ximpl;
- } catch ( javax.xml.transform.TransformerException te ) {
- throw new XPathExpressionException ( te ) ;
- }
- }
-
-
- /**
- * <p>Evaluate an 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(String expression, 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>expression</code>, <code>source</code> or <code>returnType</code> is <code>null</code>,
- * then a <code>NullPointerException</code> is thrown.</p>
- *
- * @param expression The XPath expression.
- * @param source The input source of the document to evaluate over.
- * @param returnType The desired return type.
- *
- * @return The <code>Object</code> that encapsulates the result of evaluating the expression.
- *
- * @throws XPathExpressionException If expression cannot be evaluated.
- * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}.
- * @throws NullPointerException If <code>expression</code>, <code>source</code> or <code>returnType</code>
- * is <code>null</code>.
- */
- public Object evaluate(String expression, InputSource source,
- QName returnType) throws XPathExpressionException {
- // Checking validity of different parameters
- if( source== null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"source"} );
- throw new NullPointerException ( fmsg );
- }
- if ( expression == null ) {
- String fmsg = XSLMessages.createXPATHMessage(
- XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
- new Object[] {"XPath expression"} );
- throw new NullPointerException ( fmsg );
- }
- if ( returnType == null ) {
- 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 {
-
- Document document = getParser().parse( source );
-
- XObject resultObject = eval( expression, document );
- return getResultAsType( resultObject, returnType );
- } catch ( SAXException e ) {
- throw new XPathExpressionException ( e );
- } catch( IOException e ) {
- throw new XPathExpressionException ( e );
- } catch ( javax.xml.transform.TransformerException te ) {
- Throwable nestedException = te.getException();
- if ( nestedException instanceof javax.xml.xpath.XPathFunctionException ) {
- throw (javax.xml.xpath.XPathFunctionException)nestedException;
- } else {
- throw new XPathExpressionException ( te );
- }
- }
-
- }
-
-
-
-
- /**
- * <p>Evaluate an 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(String expression, 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>expression</code> or <code>source</code> is <code>null</code>,
- * then a <code>NullPointerException</code> is thrown.</p>
- *
- * @param expression The XPath expression.
- * @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 expression cannot be evaluated.
- * @throws NullPointerException If <code>expression</code> or <code>source</code> is <code>null</code>.
- */
- public String evaluate(String expression, InputSource source)
- throws XPathExpressionException {
- return (String)this.evaluate( expression, source, XPathConstants.STRING );
- }
-
- /**
- * <p>Reset this <code>XPath</code> to its original configuration.</p>
- *
- * <p><code>XPath</code> is reset to the same state as when it was created with
- * {@link XPathFactory#newXPath()}.
- * <code>reset()</code> is designed to allow the reuse of existing <code>XPath</code>s
- * thus saving resources associated with the creation of new <code>XPath</code>s.</p>
- *
- * <p>The reset <code>XPath</code> is not guaranteed to have the same
- * {@link XPathFunctionResolver}, {@link XPathVariableResolver}
- * or {@link NamespaceContext} <code>Object</code>s, e.g. {@link Object#equals(Object obj)}.
- * It is guaranteed to have a functionally equal <code>XPathFunctionResolver</code>,
- * <code>XPathVariableResolver</code>
- * and <code>NamespaceContext</code>.</p>
- */
- public void reset() {
- this.variableResolver = this.origVariableResolver;
- this.functionResolver = this.origFunctionResolver;
- this.namespaceContext = null;
- }
-
- }