src/java.xml/share/classes/com/sun/org/apache/xpath/internal/jaxp/XPathImpl.java

Print this page

        

@@ -1,8 +1,7 @@
 /*
- * reserved comment block
- * DO NOT REMOVE OR ALTER!
+ * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
  */
 /*
  * Copyright 1999-2004 The Apache Software Foundation.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");

@@ -26,511 +25,216 @@
 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 com.sun.org.apache.xalan.internal.utils.FactoryImpl;
 import com.sun.org.apache.xalan.internal.utils.FeatureManager;
-
-import org.w3c.dom.Node;
 import org.w3c.dom.Document;
-import org.w3c.dom.traversal.NodeIterator;
-
 import org.xml.sax.InputSource;
-import org.xml.sax.SAXException;
+import javax.xml.transform.TransformerException;
+import javax.xml.xpath.XPathEvaluationResult;
 
-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
+ * javax.xml.xpath.XPath interface. This provides simple access to the results
  * of an XPath expression.
  *
- *
  * @author  Ramesh Mandava
+ *
+ * Updated 12/04/2014:
+ * New methods: evaluateExpression
+ * Refactored to share code with XPathExpressionImpl.
  */
-public class XPathImpl implements javax.xml.xpath.XPath {
+public class XPathImpl extends XPathImplUtil 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;
-    private boolean useServiceMechanism = true;
-    private final FeatureManager featureManager;
 
-    XPathImpl( XPathVariableResolver vr, XPathFunctionResolver fr ) {
+    XPathImpl(XPathVariableResolver vr, XPathFunctionResolver fr) {
         this(vr, fr, false, true, new FeatureManager());
     }
 
-    XPathImpl( XPathVariableResolver vr, XPathFunctionResolver fr,
+    XPathImpl(XPathVariableResolver vr, XPathFunctionResolver fr,
             boolean featureSecureProcessing, boolean useServiceMechanism,
             FeatureManager featureManager) {
         this.origVariableResolver = this.variableResolver = vr;
         this.origFunctionResolver = this.functionResolver = fr;
         this.featureSecureProcessing = featureSecureProcessing;
         this.useServiceMechanism = useServiceMechanism;
         this.featureManager = featureManager;
     }
 
-    /**
-     * <p>Establishes a variable resolver.</p>
-     *
-     * @param resolver Variable Resolver
-     */
+    @Override
     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 );
-        }
+        requireNonNull(resolver, "XPathVariableResolver");
         this.variableResolver = resolver;
     }
 
-    /**
-     * <p>Returns the current variable resolver.</p>
-     *
-     * @return Current variable resolver
-     */
+    @Override
     public XPathVariableResolver getXPathVariableResolver() {
         return variableResolver;
     }
 
-    /**
-     * <p>Establishes a function resolver.</p>
-     *
-     * @param resolver XPath function resolver
-     */
+    @Override
     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 );
-        }
+        requireNonNull(resolver, "XPathFunctionResolver");
         this.functionResolver = resolver;
     }
 
-    /**
-     * <p>Returns the current function resolver.</p>
-     *
-     * @return Current function resolver
-     */
+    @Override
     public XPathFunctionResolver getXPathFunctionResolver() {
         return functionResolver;
     }
 
-    /**
-     * <p>Establishes a namespace context.</p>
-     *
-     * @param nsContext Namespace context to use
-     */
+    @Override
     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 );
-        }
+        requireNonNull(nsContext, "NamespaceContext");
         this.namespaceContext = nsContext;
-        this.prefixResolver = new JAXPPrefixResolver ( nsContext );
+        this.prefixResolver = new JAXPPrefixResolver (nsContext);
     }
 
-    /**
-     * <p>Returns the current namespace context.</p>
-     *
-     * @return Current Namespace context
-     */
+    @Override
     public NamespaceContext getNamespaceContext() {
         return namespaceContext;
     }
 
-    private static Document d = null;
-
-    private 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 = FactoryImpl.getDOMFactory(useServiceMechanism);
-            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);
-        }
-    }
-
-
+    /**
+     * Evaluate an {@code XPath} expression in the specified context.
+     * @param expression The XPath expression.
+     * @param contextItem The starting context.
+     * @return an XObject as the result of evaluating the expression
+     * @throws TransformerException if evaluating fails
+     */
     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, featureManager );
-            xpathSupport = new com.sun.org.apache.xpath.internal.XPathContext( jep );
-        } else {
-            xpathSupport = new com.sun.org.apache.xpath.internal.XPathContext();
-        }
+        throws TransformerException {
+        requireNonNull(expression, "XPath expression");
+        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);
 
-        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 eval(contextItem, xpath);
         }
 
-        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>.
-     */
+    @Override
     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 );
-        }
+        //this check is necessary before calling eval to maintain binary compatibility
+        requireNonNull(expression, "XPath expression");
+        isSupported(returnType);
 
         try {
 
-            XObject resultObject = eval( expression, item );
-            return getResultAsType( resultObject, returnType );
-        } catch ( java.lang.NullPointerException npe ) {
+            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 ) {
+            throw new XPathExpressionException (npe);
+        } catch (TransformerException te) {
             Throwable nestedException = te.getException();
-            if ( nestedException instanceof javax.xml.xpath.XPathFunctionException ) {
+            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 );
+                // 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>.
-     */
+    @Override
     public String evaluate(String expression, Object item)
         throws XPathExpressionException {
-        return (String)this.evaluate( expression, item, XPathConstants.STRING );
+        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>.
-     */
+    @Override
     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 );
-        }
+        requireNonNull(expression, "XPath expression");
         try {
             com.sun.org.apache.xpath.internal.XPath xpath = new XPath (expression, null,
-                    prefixResolver, com.sun.org.apache.xpath.internal.XPath.SELECT );
+                    prefixResolver, com.sun.org.apache.xpath.internal.XPath.SELECT);
             // Can have errorListener
             XPathExpressionImpl ximpl = new XPathExpressionImpl (xpath,
                     prefixResolver, functionResolver, variableResolver,
-                    featureSecureProcessing, useServiceMechanism, featureManager );
+                    featureSecureProcessing, useServiceMechanism, featureManager);
             return ximpl;
-        } catch ( javax.xml.transform.TransformerException te ) {
-            throw new XPathExpressionException ( te ) ;
+        } catch (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>.
-     */
+    @Override
     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 );
-        }
+        isSupported(returnType);
 
-        //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 ) {
+            Document document = getDocument(source);
+            XObject resultObject = eval(expression, document);
+            return getResultAsType(resultObject, returnType);
+        } catch (TransformerException te) {
             Throwable nestedException = te.getException();
-            if ( nestedException instanceof javax.xml.xpath.XPathFunctionException ) {
+            if (nestedException instanceof javax.xml.xpath.XPathFunctionException) {
                 throw (javax.xml.xpath.XPathFunctionException)nestedException;
             } else {
-                throw new XPathExpressionException ( te );
+                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>.
-     */
+    @Override
     public String evaluate(String expression, InputSource source)
         throws XPathExpressionException {
-        return (String)this.evaluate( expression, source, XPathConstants.STRING );
+        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>
-     */
+    @Override
     public void reset() {
         this.variableResolver = this.origVariableResolver;
         this.functionResolver = this.origFunctionResolver;
         this.namespaceContext = null;
     }
 
+    @Override
+    public <T> T evaluateExpression(String expression, Object item, Class<T> type)
+            throws XPathExpressionException {
+        isSupportedClassType(type);
+        try {
+            XObject resultObject = eval(expression, item);
+            if (type.isAssignableFrom(XPathEvaluationResult.class)) {
+                XPathEvaluationResult<?> x = getXPathResult(resultObject);
+
+                return (T)x;
+            } else {
+                return XPathResultImpl.getValue(resultObject, type);
+            }
+        } catch (TransformerException te) {
+            throw new XPathExpressionException (te);
+        }
+    }
+
+    @Override
+    public XPathEvaluationResult evaluateExpression(String expression, Object item)
+            throws XPathExpressionException {
+        return evaluateExpression(expression, item, XPathEvaluationResult.class);
+    }
+
+    @Override
+    public <T> T evaluateExpression(String expression, InputSource source, Class<T> type)
+            throws XPathExpressionException {
+        Document document = getDocument(source);
+        return evaluateExpression(expression, document, type);
+    }
+
+    @Override
+    public XPathEvaluationResult evaluateExpression(String expression, InputSource source)
+            throws XPathExpressionException {
+        return evaluateExpression(expression, source, XPathEvaluationResult.class);
+    }
 }