org.htmlunit.xpath.XPathContext Maven / Gradle / Ivy
Show all versions of htmlunit-xpath Show documentation
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.htmlunit.xpath;
import java.util.Stack;
import javax.xml.transform.ErrorListener;
import javax.xml.transform.URIResolver;
import org.htmlunit.xpath.axes.SubContextList;
import org.htmlunit.xpath.res.XPATHErrorResources;
import org.htmlunit.xpath.res.XPATHMessages;
import org.htmlunit.xpath.xml.dtm.DTM;
import org.htmlunit.xpath.xml.dtm.DTMManager;
import org.htmlunit.xpath.xml.utils.PrefixResolver;
/**
* Default class for the runtime execution context for XPath.
*
* This class extends DTMManager but does not directly implement it.
*/
public class XPathContext extends DTMManager {
/**
* Though XPathContext context extends the DTMManager, it really is a proxy for this object, which
* is the real DTMManager.
*/
protected DTMManager m_dtmManager = DTMManager.newInstance();
/**
* Return the DTMManager object. Though XPathContext context extends the DTMManager, it really is
* a proxy for the real DTMManager. If a caller needs to make a lot of calls to the DTMManager, it
* is faster if it gets the real one from this function.
*/
public DTMManager getDTMManager() {
return m_dtmManager;
}
/** {@inheritDoc} */
@Override
public DTM getDTM(
final javax.xml.transform.Source source,
final boolean unique,
final boolean incremental,
final boolean doIndexing) {
return m_dtmManager.getDTM(source, unique, incremental, doIndexing);
}
/** {@inheritDoc} */
@Override
public DTM getDTM(final int nodeHandle) {
return m_dtmManager.getDTM(nodeHandle);
}
/** {@inheritDoc} */
@Override
public int getDTMHandleFromNode(final org.w3c.dom.Node node) {
return m_dtmManager.getDTMHandleFromNode(node);
}
/**
* Create an XPathContext instance. This is equivalent to calling the {@link
* #XPathContext(boolean)} constructor with the value true.
*/
public XPathContext() {
this(true);
}
/**
* Create an XPathContext instance.
*
* @param recursiveVarContext A boolean value indicating whether the XPath context
* needs to support pushing of scopes for variable resolution
*/
public XPathContext(final boolean recursiveVarContext) {
m_prefixResolvers.push(null);
m_currentNodes.push(DTM.NULL);
}
/** Reset for new run. */
public void reset() {
m_dtmManager = DTMManager.newInstance();
m_axesIteratorStack.removeAllElements();
m_currentNodes.removeAllElements();
m_predicatePos.removeAllElements();
m_prefixResolvers.removeAllElements();
m_prefixResolvers.push(null);
m_currentNodes.push(DTM.NULL);
}
// =================================================
/** The ErrorListener where errors and warnings are to be reported. */
private ErrorListener m_errorListener;
/**
* A default ErrorListener in case our m_errorListener was not specified and our owner either does
* not have an ErrorListener or has a null one.
*/
private ErrorListener m_defaultErrorListener;
/**
* Get the ErrorListener where errors and warnings are to be reported.
*
* @return A non-null ErrorListener reference.
*/
public final ErrorListener getErrorListener() {
if (null != m_errorListener) {
return m_errorListener;
}
if (null == m_defaultErrorListener) {
m_defaultErrorListener = new org.htmlunit.xpath.xml.utils.DefaultErrorHandler();
}
return m_defaultErrorListener;
}
/**
* Set the ErrorListener where errors and warnings are to be reported.
*
* @param listener A non-null ErrorListener reference.
*/
public void setErrorListener(final ErrorListener listener) throws IllegalArgumentException {
if (listener == null) {
throw new IllegalArgumentException(
XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_NULL_ERROR_HANDLER, null));
}
m_errorListener = listener;
}
// =================================================
/**
* The TrAX URI Resolver for resolving URIs from the document(...) function to source tree nodes.
*/
private URIResolver m_uriResolver;
/**
* Get the URIResolver associated with this execution context.
*
* @return a URI resolver, which may be null.
*/
public final URIResolver getURIResolver() {
return m_uriResolver;
}
/**
* Set the URIResolver associated with this execution context.
*
* @param resolver the URIResolver to be associated with this execution context, may be null to
* clear an already set resolver.
*/
public void setURIResolver(final URIResolver resolver) {
m_uriResolver = resolver;
}
// ==========================================================
// SECTION: Execution context state tracking
// ==========================================================
/** The ammount to use for stacks that record information during the recursive execution. */
public static final int RECURSIONLIMIT = 1024 * 4;
/**
* The stack of current node objects. Not
* to be confused with the current node list. %REVIEW% Note that there are no bounds check and
* resize for this stack, so if it is blown, it's all over.
*/
private final Stack m_currentNodes = new Stack<>();
/**
* Get the current context node.
*
* @return the current node.
*/
public final int getCurrentNode() {
return m_currentNodes.peek();
}
/**
* Set the current context node and expression node.
*
* @param cn the current node.
*/
public final void pushCurrentNodeAndExpression(final int cn) {
m_currentNodes.push(cn);
}
/** Set the current context node. */
public final void popCurrentNodeAndExpression() {
m_currentNodes.pop();
}
/**
* Set the current context node.
*
* @param n the current node.
*/
public final void pushCurrentNode(final int n) {
m_currentNodes.push(n);
}
/** Pop the current context node. */
public final void popCurrentNode() {
m_currentNodes.pop();
}
private final Stack m_predicatePos = new Stack<>();
public final int getPredicatePos() {
return m_predicatePos.peek();
}
public final void pushPredicatePos(final int n) {
m_predicatePos.push(n);
}
public final void popPredicatePos() {
m_predicatePos.pop();
}
private final Stack m_prefixResolvers = new Stack<>();
/**
* Get the current namespace context for the xpath.
*
* @return the current prefix resolver for resolving prefixes to namespace URLs.
*/
public final PrefixResolver getNamespaceContext() {
return m_prefixResolvers.peek();
}
/**
* Get the current namespace context for the xpath.
*
* @param pr the prefix resolver to be used for resolving prefixes to namespace URLs.
*/
public final void setNamespaceContext(final PrefixResolver pr) {
m_prefixResolvers.pop();
m_prefixResolvers.push(pr);
}
/**
* Push a current namespace context for the xpath.
*
* @param pr the prefix resolver to be used for resolving prefixes to namespace URLs.
*/
public final void pushNamespaceContext(final PrefixResolver pr) {
m_prefixResolvers.push(pr);
}
/** Pop the current namespace context for the xpath. */
public final void popNamespaceContext() {
m_prefixResolvers.pop();
}
// ==========================================================
// SECTION: Current TreeWalker contexts (for internal use)
// ==========================================================
/** Stack of AxesIterators. */
private final Stack m_axesIteratorStack = new Stack<>();
/**
* Push a TreeWalker on the stack.
*
* @param iter A sub-context AxesWalker.
*/
public final void pushSubContextList(final SubContextList iter) {
m_axesIteratorStack.push(iter);
}
/** Pop the last pushed axes iterator. */
public final void popSubContextList() {
m_axesIteratorStack.pop();
}
/**
* Get the current axes iterator, or return null if none.
*
* @return the sub-context node list.
*/
public SubContextList getSubContextList() {
return m_axesIteratorStack.isEmpty() ? null : m_axesIteratorStack.peek();
}
// ==========================================================
// SECTION: Implementation of ExpressionContext interface
// ==========================================================
}