/* * reserved comment block * DO NOT REMOVE OR ALTER! */ /* * Copyright 2002-2005 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: XPathResultImpl.java,v 1.2.4.1 2005/09/10 04:18:54 jeffsuttor Exp $ */ package com.sun.org.apache.xpath.internal.domapi; import javax.xml.transform.TransformerException; import com.sun.org.apache.xpath.internal.XPath; import com.sun.org.apache.xpath.internal.objects.XObject; import com.sun.org.apache.xpath.internal.res.XPATHErrorResources; import com.sun.org.apache.xpath.internal.res.XPATHMessages; import org.w3c.dom.DOMException; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.w3c.dom.events.Event; import org.w3c.dom.events.EventListener; import org.w3c.dom.events.EventTarget; import org.w3c.dom.traversal.NodeIterator; import org.w3c.dom.xpath.XPathException; import org.w3c.dom.xpath.XPathResult; /** * * The class provides an implementation XPathResult according * to the DOM L3 XPath Specification, Working Group Note 26 February 2004. * *

See also the Document Object Model (DOM) Level 3 XPath Specification.

* *

The XPathResult interface represents the result of the * evaluation of an XPath expression within the context of a particular * node. Since evaluation of an XPath expression can result in various * result types, this object makes it possible to discover and manipulate * the type and value of the result.

* *

This implementation wraps an XObject. * * @see com.sun.org.apache.xpath.internal.objects.XObject * @see org.w3c.dom.xpath.XPathResult * * @xsl.usage internal */ class XPathResultImpl implements XPathResult, EventListener { /** * The wrapped XObject */ final private XObject m_resultObj; /** * The xpath object that wraps the expression used for this result. */ final private XPath m_xpath; /** * This the type specified by the user during construction. Typically * the constructor will be called by com.sun.org.apache.xpath.internal.XPath.evaluate(). */ final private short m_resultType; private boolean m_isInvalidIteratorState = false; /** * Only used to attach a mutation event handler when specified * type is an iterator type. */ final private Node m_contextNode; /** * The iterator, if this is an iterator type. */ private NodeIterator m_iterator = null;; /** * The list, if this is a snapshot type. */ private NodeList m_list = null; /** * Constructor for XPathResultImpl. * * For internal use only. */ XPathResultImpl(short type, XObject result, Node contextNode, XPath xpath) { // Check that the type is valid if (!isValidType(type)) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_INVALID_XPATH_TYPE, new Object[] {new Integer(type)}); throw new XPathException(XPathException.TYPE_ERR,fmsg); // Invalid XPath type argument: {0} } // Result object should never be null! if (null == result) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_EMPTY_XPATH_RESULT, null); throw new XPathException(XPathException.INVALID_EXPRESSION_ERR,fmsg); // Empty XPath result object } this.m_resultObj = result; this.m_contextNode = contextNode; this.m_xpath = xpath; // If specified result was ANY_TYPE, determine XObject type if (type == ANY_TYPE) { this.m_resultType = getTypeFromXObject(result); } else { this.m_resultType = type; } // If the context node supports DOM Events and the type is one of the iterator // types register this result as an event listener if (((m_resultType == XPathResult.ORDERED_NODE_ITERATOR_TYPE) || (m_resultType == XPathResult.UNORDERED_NODE_ITERATOR_TYPE))) { addEventListener(); }// else can we handle iterator types if contextNode doesn't support EventTarget?? // If this is an iterator type get the iterator if ((m_resultType == ORDERED_NODE_ITERATOR_TYPE) || (m_resultType == UNORDERED_NODE_ITERATOR_TYPE) || (m_resultType == ANY_UNORDERED_NODE_TYPE) || (m_resultType == FIRST_ORDERED_NODE_TYPE)) { try { m_iterator = m_resultObj.nodeset(); } catch (TransformerException te) { // probably not a node type String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_INCOMPATIBLE_TYPES, new Object[] {m_xpath.getPatternString(), getTypeString(getTypeFromXObject(m_resultObj)),getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR, fmsg); // "The XPathResult of XPath expression {0} has an XPathResultType of {1} which cannot be coerced into the specified XPathResultType of {2}."}, } // If user requested ordered nodeset and result is unordered // need to sort...TODO // if ((m_resultType == ORDERED_NODE_ITERATOR_TYPE) && // (!(((DTMNodeIterator)m_iterator).getDTMIterator().isDocOrdered()))) { // // } // If it's a snapshot type, get the nodelist } else if ((m_resultType == UNORDERED_NODE_SNAPSHOT_TYPE) || (m_resultType == ORDERED_NODE_SNAPSHOT_TYPE)) { try { m_list = m_resultObj.nodelist(); } catch (TransformerException te) { // probably not a node type String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_INCOMPATIBLE_TYPES, new Object[] {m_xpath.getPatternString(), getTypeString(getTypeFromXObject(m_resultObj)),getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR, fmsg); // "The XPathResult of XPath expression {0} has an XPathResultType of {1} which cannot be coerced into the specified XPathResultType of {2}."}, } } } /** * @see org.w3c.dom.xpath.XPathResult#getResultType() */ public short getResultType() { return m_resultType; } /** * The value of this number result. * @exception XPathException * TYPE_ERR: raised if resultType is not * NUMBER_TYPE. * @see org.w3c.dom.xpath.XPathResult#getNumberValue() */ public double getNumberValue() throws XPathException { if (getResultType() != NUMBER_TYPE) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_CANT_CONVERT_XPATHRESULTTYPE_TO_NUMBER, new Object[] {m_xpath.getPatternString(), getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR,fmsg); // "The XPathResult of XPath expression {0} has an XPathResultType of {1} which cannot be converted to a number" } else { try { return m_resultObj.num(); } catch (Exception e) { // Type check above should prevent this exception from occurring. throw new XPathException(XPathException.TYPE_ERR,e.getMessage()); } } } /** * The value of this string result. * @exception XPathException * TYPE_ERR: raised if resultType is not * STRING_TYPE. * * @see org.w3c.dom.xpath.XPathResult#getStringValue() */ public String getStringValue() throws XPathException { if (getResultType() != STRING_TYPE) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_CANT_CONVERT_TO_STRING, new Object[] {m_xpath.getPatternString(), m_resultObj.getTypeString()}); throw new XPathException(XPathException.TYPE_ERR,fmsg); // "The XPathResult of XPath expression {0} has an XPathResultType of {1} which cannot be converted to a string." } else { try { return m_resultObj.str(); } catch (Exception e) { // Type check above should prevent this exception from occurring. throw new XPathException(XPathException.TYPE_ERR,e.getMessage()); } } } /** * @see org.w3c.dom.xpath.XPathResult#getBooleanValue() */ public boolean getBooleanValue() throws XPathException { if (getResultType() != BOOLEAN_TYPE) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_CANT_CONVERT_TO_BOOLEAN, new Object[] {m_xpath.getPatternString(), getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR,fmsg); // "The XPathResult of XPath expression {0} has an XPathResultType of {1} which cannot be converted to a boolean." } else { try { return m_resultObj.bool(); } catch (TransformerException e) { // Type check above should prevent this exception from occurring. throw new XPathException(XPathException.TYPE_ERR,e.getMessage()); } } } /** * The value of this single node result, which may be null. * @exception XPathException * TYPE_ERR: raised if resultType is not * ANY_UNORDERED_NODE_TYPE or * FIRST_ORDERED_NODE_TYPE. * * @see org.w3c.dom.xpath.XPathResult#getSingleNodeValue() */ public Node getSingleNodeValue() throws XPathException { if ((m_resultType != ANY_UNORDERED_NODE_TYPE) && (m_resultType != FIRST_ORDERED_NODE_TYPE)) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_CANT_CONVERT_TO_SINGLENODE, new Object[] {m_xpath.getPatternString(), getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR,fmsg); // "The XPathResult of XPath expression {0} has an XPathResultType of {1} which cannot be converted to a single node. // This method applies only to types ANY_UNORDERED_NODE_TYPE and FIRST_ORDERED_NODE_TYPE." } NodeIterator result = null; try { result = m_resultObj.nodeset(); } catch (TransformerException te) { throw new XPathException(XPathException.TYPE_ERR,te.getMessage()); } if (null == result) return null; Node node = result.nextNode(); // Wrap "namespace node" in an XPathNamespace if (isNamespaceNode(node)) { return new XPathNamespaceImpl(node); } else { return node; } } /** * @see org.w3c.dom.xpath.XPathResult#getInvalidIteratorState() */ public boolean getInvalidIteratorState() { return m_isInvalidIteratorState; } /** * The number of nodes in the result snapshot. Valid values for * snapshotItem indices are 0 to * snapshotLength-1 inclusive. * @exception XPathException * TYPE_ERR: raised if resultType is not * UNORDERED_NODE_SNAPSHOT_TYPE or * ORDERED_NODE_SNAPSHOT_TYPE. * * @see org.w3c.dom.xpath.XPathResult#getSnapshotLength() */ public int getSnapshotLength() throws XPathException { if ((m_resultType != UNORDERED_NODE_SNAPSHOT_TYPE) && (m_resultType != ORDERED_NODE_SNAPSHOT_TYPE)) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_CANT_GET_SNAPSHOT_LENGTH, new Object[] {m_xpath.getPatternString(), getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR,fmsg); // "The method getSnapshotLength cannot be called on the XPathResult of XPath expression {0} because its XPathResultType is {1}. } return m_list.getLength(); } /** * Iterates and returns the next node from the node set or * nullif there are no more nodes. * @return Returns the next node. * @exception XPathException * TYPE_ERR: raised if resultType is not * UNORDERED_NODE_ITERATOR_TYPE or * ORDERED_NODE_ITERATOR_TYPE. * @exception DOMException * INVALID_STATE_ERR: The document has been mutated since the result was * returned. * @see org.w3c.dom.xpath.XPathResult#iterateNext() */ public Node iterateNext() throws XPathException, DOMException { if ((m_resultType != UNORDERED_NODE_ITERATOR_TYPE) && (m_resultType != ORDERED_NODE_ITERATOR_TYPE)) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_NON_ITERATOR_TYPE, new Object[] {m_xpath.getPatternString(), getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR, fmsg); // "The method iterateNext cannot be called on the XPathResult of XPath expression {0} because its XPathResultType is {1}. // This method applies only to types UNORDERED_NODE_ITERATOR_TYPE and ORDERED_NODE_ITERATOR_TYPE."}, } if (getInvalidIteratorState()) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_DOC_MUTATED, null); throw new DOMException(DOMException.INVALID_STATE_ERR,fmsg); // Document mutated since result was returned. Iterator is invalid. } Node node = m_iterator.nextNode(); if(null == node) removeEventListener(); // JIRA 1673 // Wrap "namespace node" in an XPathNamespace if (isNamespaceNode(node)) { return new XPathNamespaceImpl(node); } else { return node; } } /** * Returns the indexth item in the snapshot collection. If * index is greater than or equal to the number of nodes in * the list, this method returns null. Unlike the iterator * result, the snapshot does not become invalid, but may not correspond * to the current document if it is mutated. * @param index Index into the snapshot collection. * @return The node at the indexth position in the * NodeList, or null if that is not a valid * index. * @exception XPathException * TYPE_ERR: raised if resultType is not * UNORDERED_NODE_SNAPSHOT_TYPE or * ORDERED_NODE_SNAPSHOT_TYPE. * * @see org.w3c.dom.xpath.XPathResult#snapshotItem(int) */ public Node snapshotItem(int index) throws XPathException { if ((m_resultType != UNORDERED_NODE_SNAPSHOT_TYPE) && (m_resultType != ORDERED_NODE_SNAPSHOT_TYPE)) { String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_NON_SNAPSHOT_TYPE, new Object[] {m_xpath.getPatternString(), getTypeString(m_resultType)}); throw new XPathException(XPathException.TYPE_ERR, fmsg); // "The method snapshotItem cannot be called on the XPathResult of XPath expression {0} because its XPathResultType is {1}. // This method applies only to types UNORDERED_NODE_SNAPSHOT_TYPE and ORDERED_NODE_SNAPSHOT_TYPE."}, } Node node = m_list.item(index); // Wrap "namespace node" in an XPathNamespace if (isNamespaceNode(node)) { return new XPathNamespaceImpl(node); } else { return node; } } /** * Check if the specified type is one of the supported types. * @param type The specified type * * @return true If the specified type is supported; otherwise, returns false. */ static boolean isValidType( short type ) { switch (type) { case ANY_TYPE: case NUMBER_TYPE: case STRING_TYPE: case BOOLEAN_TYPE: case UNORDERED_NODE_ITERATOR_TYPE: case ORDERED_NODE_ITERATOR_TYPE: case UNORDERED_NODE_SNAPSHOT_TYPE: case ORDERED_NODE_SNAPSHOT_TYPE: case ANY_UNORDERED_NODE_TYPE: case FIRST_ORDERED_NODE_TYPE: return true; default: return false; } } /** * @see org.w3c.dom.events.EventListener#handleEvent(Event) */ public void handleEvent(Event event) { if (event.getType().equals("DOMSubtreeModified")) { // invalidate the iterator m_isInvalidIteratorState = true; // deregister as a listener to reduce computational load removeEventListener(); } } /** * Given a request type, return the equivalent string. * For diagnostic purposes. * * @return type string */ private String getTypeString(int type) { switch (type) { case ANY_TYPE: return "ANY_TYPE"; case ANY_UNORDERED_NODE_TYPE: return "ANY_UNORDERED_NODE_TYPE"; case BOOLEAN_TYPE: return "BOOLEAN"; case FIRST_ORDERED_NODE_TYPE: return "FIRST_ORDERED_NODE_TYPE"; case NUMBER_TYPE: return "NUMBER_TYPE"; case ORDERED_NODE_ITERATOR_TYPE: return "ORDERED_NODE_ITERATOR_TYPE"; case ORDERED_NODE_SNAPSHOT_TYPE: return "ORDERED_NODE_SNAPSHOT_TYPE"; case STRING_TYPE: return "STRING_TYPE"; case UNORDERED_NODE_ITERATOR_TYPE: return "UNORDERED_NODE_ITERATOR_TYPE"; case UNORDERED_NODE_SNAPSHOT_TYPE: return "UNORDERED_NODE_SNAPSHOT_TYPE"; default: return "#UNKNOWN"; } } /** * Given an XObject, determine the corresponding DOM XPath type * * @return type string */ private short getTypeFromXObject(XObject object) { switch (object.getType()) { case XObject.CLASS_BOOLEAN: return BOOLEAN_TYPE; case XObject.CLASS_NODESET: return UNORDERED_NODE_ITERATOR_TYPE; case XObject.CLASS_NUMBER: return NUMBER_TYPE; case XObject.CLASS_STRING: return STRING_TYPE; // XPath 2.0 types // case XObject.CLASS_DATE: // case XObject.CLASS_DATETIME: // case XObject.CLASS_DTDURATION: // case XObject.CLASS_GDAY: // case XObject.CLASS_GMONTH: // case XObject.CLASS_GMONTHDAY: // case XObject.CLASS_GYEAR: // case XObject.CLASS_GYEARMONTH: // case XObject.CLASS_TIME: // case XObject.CLASS_YMDURATION: return STRING_TYPE; // treat all date types as strings? case XObject.CLASS_RTREEFRAG: return UNORDERED_NODE_ITERATOR_TYPE; case XObject.CLASS_NULL: return ANY_TYPE; // throw exception ? default: return ANY_TYPE; // throw exception ? } } /** * Given a node, determine if it is a namespace node. * * @param node * * @return boolean Returns true if this is a namespace node; otherwise, returns false. */ private boolean isNamespaceNode(Node node) { if ((null != node) && (node.getNodeType() == Node.ATTRIBUTE_NODE) && (node.getNodeName().startsWith("xmlns:") || node.getNodeName().equals("xmlns"))) { return true; } else { return false; } } /** * Add m_contextNode to Event Listner to listen for Mutations Events * */ private void addEventListener(){ if(m_contextNode instanceof EventTarget) ((EventTarget)m_contextNode).addEventListener("DOMSubtreeModified",this,true); } /** * Remove m_contextNode to Event Listner to listen for Mutations Events * */ private void removeEventListener(){ if(m_contextNode instanceof EventTarget) ((EventTarget)m_contextNode).removeEventListener("DOMSubtreeModified",this,true); } }