/*
* 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 1.3 2005/09/27 09:40:43 sunithareddy 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.dtm.DTM;
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: 1.3 $
* @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 )
xobj = xpath.execute(xpathSupport, DTM.NULL, prefixResolver);
else
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 );
}
}
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