/*
$Id: DefaultNameStep.java,v 1.51 2006/11/30 18:49:27 elharo Exp $
Copyright 2003 The Werken Company. All Rights Reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
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* Redistributions of source code must retain the above copyright
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* Redistributions in binary form must reproduce the above copyright
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* Neither the name of the Jaxen Project nor the names of its
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package org.jaxen.expr;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.jaxen.Context;
import org.jaxen.ContextSupport;
import org.jaxen.JaxenException;
import org.jaxen.UnresolvableException;
import org.jaxen.Navigator;
import org.jaxen.expr.iter.IterableAxis;
import org.jaxen.saxpath.Axis;
/**
* Expression object that represents any flavor
* of name-test steps within an XPath.
* <p>
* This includes simple steps, such as "foo",
* non-default-axis steps, such as "following-sibling::foo"
* or "@foo", and namespace-aware steps, such
* as "foo:bar".
*
* @author bob mcwhirter (bob@werken.com)
* @author Stephen Colebourne
* @deprecated this class will become non-public in the future;
* use the interface instead
*/
public class DefaultNameStep extends DefaultStep implements NameStep {
/**
*
*/
private static final long serialVersionUID = 428414912247718390L;
/**
* Our prefix, bound through the current Context.
* The empty-string ("") if no prefix was specified.
* Decidedly NOT-NULL, due to SAXPath constraints.
* This is the 'foo' in 'foo:bar'.
*/
private String prefix;
/**
* Our local-name.
* This is the 'bar' in 'foo:bar'.
*/
private String localName;
/** Quick flag denoting if the local name was '*' */
private boolean matchesAnyName;
/** Quick flag denoting if we have a namespace prefix **/
private boolean hasPrefix;
/**
* Constructor.
*
* @param axis the axis to work through
* @param prefix the name prefix
* @param localName the local name
* @param predicateSet the set of predicates
*/
public DefaultNameStep(IterableAxis axis,
String prefix,
String localName,
PredicateSet predicateSet) {
super(axis, predicateSet);
this.prefix = prefix;
this.localName = localName;
this.matchesAnyName = "*".equals(localName);
this.hasPrefix = (this.prefix != null && this.prefix.length() > 0);
}
/**
* Gets the namespace prefix.
*
* @return the prefix
*/
public String getPrefix() {
return this.prefix;
}
/**
* Gets the local name.
*
* @return the local name
*/
public String getLocalName() {
return this.localName;
}
/**
* Does this step match any name? (i.e. Is it '*'?)
*
* @return true if it matches any name
*/
public boolean isMatchesAnyName() {
return matchesAnyName;
}
/**
* Gets the step as a fully defined XPath.
*
* @return the full XPath for this step
*/
public String getText() {
StringBuffer buf = new StringBuffer(64);
buf.append(getAxisName()).append("::");
if (getPrefix() != null && getPrefix().length() > 0) {
buf.append(getPrefix()).append(':');
}
return buf.append(getLocalName()).append(super.getText()).toString();
}
/**
* Evaluate the context node set to find the new node set.
* <p>
* This method overrides the version in <code>DefaultStep</code> for performance.
*/
public List evaluate(Context context) throws JaxenException {
List contextNodeSet = context.getNodeSet();
int contextSize = contextNodeSet.size();
// optimize for context size 0
if (contextSize == 0) {
return Collections.EMPTY_LIST;
}
ContextSupport support = context.getContextSupport();
IterableAxis iterableAxis = getIterableAxis();
boolean namedAccess = (!matchesAnyName && iterableAxis.supportsNamedAccess(support));
// optimize for context size 1 (common case, avoids lots of object creation)
if (contextSize == 1) {
Object contextNode = contextNodeSet.get(0);
if (namedAccess) {
// get the iterator over the nodes and check it
String uri = null;
if (hasPrefix) {
uri = support.translateNamespacePrefixToUri(prefix);
if (uri == null) {
throw new UnresolvableException("XPath expression uses unbound namespace prefix " + prefix);
}
}
Iterator axisNodeIter = iterableAxis.namedAccessIterator(
contextNode, support, localName, prefix, uri);
if (axisNodeIter == null || axisNodeIter.hasNext() == false) {
return Collections.EMPTY_LIST;
}
// convert iterator to list for predicate test
// no need to filter as named access guarantees this
List newNodeSet = new ArrayList();
while (axisNodeIter.hasNext()) {
newNodeSet.add(axisNodeIter.next());
}
// evaluate the predicates
return getPredicateSet().evaluatePredicates(newNodeSet, support);
}
else {
// get the iterator over the nodes and check it
Iterator axisNodeIter = iterableAxis.iterator(contextNode, support);
if (axisNodeIter == null || axisNodeIter.hasNext() == false) {
return Collections.EMPTY_LIST;
}
// run through iterator, filtering using matches()
// adding to list for predicate test
List newNodeSet = new ArrayList(contextSize);
while (axisNodeIter.hasNext()) {
Object eachAxisNode = axisNodeIter.next();
if (matches(eachAxisNode, support)) {
newNodeSet.add(eachAxisNode);
}
}
// evaluate the predicates
return getPredicateSet().evaluatePredicates(newNodeSet, support);
}
}
// full case
IdentitySet unique = new IdentitySet();
List interimSet = new ArrayList(contextSize);
List newNodeSet = new ArrayList(contextSize);
if (namedAccess) {
String uri = null;
if (hasPrefix) {
uri = support.translateNamespacePrefixToUri(prefix);
if (uri == null) {
throw new UnresolvableException("XPath expression uses unbound namespace prefix " + prefix);
}
}
for (int i = 0; i < contextSize; ++i) {
Object eachContextNode = contextNodeSet.get(i);
Iterator axisNodeIter = iterableAxis.namedAccessIterator(
eachContextNode, support, localName, prefix, uri);
if (axisNodeIter == null || axisNodeIter.hasNext() == false) {
continue;
}
// ensure only one of each node in the result
while (axisNodeIter.hasNext()) {
Object eachAxisNode = axisNodeIter.next();
if (! unique.contains(eachAxisNode)) {
unique.add(eachAxisNode);
interimSet.add(eachAxisNode);
}
}
// evaluate the predicates
newNodeSet.addAll(getPredicateSet().evaluatePredicates(interimSet, support));
interimSet.clear();
}
} else {
for (int i = 0; i < contextSize; ++i) {
Object eachContextNode = contextNodeSet.get(i);
Iterator axisNodeIter = axisIterator(eachContextNode, support);
if (axisNodeIter == null || axisNodeIter.hasNext() == false) {
continue;
}
/* See jaxen-106. Might be able to optimize this by doing
* specific matching for individual axes. For instance on namespace axis
* we should only get namespace nodes and on attribute axes we only get
* attribute nodes. Self and parent axes have single members.
* Children, descendant, ancestor, and sibling axes never
* see any attributes or namespaces
*/
// ensure only unique matching nodes in the result
while (axisNodeIter.hasNext()) {
Object eachAxisNode = axisNodeIter.next();
if (matches(eachAxisNode, support)) {
if (! unique.contains(eachAxisNode)) {
unique.add(eachAxisNode);
interimSet.add(eachAxisNode);
}
}
}
// evaluate the predicates
newNodeSet.addAll(getPredicateSet().evaluatePredicates(interimSet, support));
interimSet.clear();
}
}
return newNodeSet;
}
/**
* Checks whether the node matches this step.
*
* @param node the node to check
* @param contextSupport the context support
* @return true if matches
* @throws JaxenException
*/
public boolean matches(Object node, ContextSupport contextSupport) throws JaxenException {
Navigator nav = contextSupport.getNavigator();
String myUri = null;
String nodeName = null;
String nodeUri = null;
if (nav.isElement(node)) {
nodeName = nav.getElementName(node);
nodeUri = nav.getElementNamespaceUri(node);
}
else if (nav.isText(node)) {
return false;
}
else if (nav.isAttribute(node)) {
if (getAxis() != Axis.ATTRIBUTE) {
return false;
}
nodeName = nav.getAttributeName(node);
nodeUri = nav.getAttributeNamespaceUri(node);
}
else if (nav.isDocument(node)) {
return false;
}
else if (nav.isNamespace(node)) {
if (getAxis() != Axis.NAMESPACE) {
// Only works for namespace::*
return false;
}
nodeName = nav.getNamespacePrefix(node);
}
else {
return false;
}
if (hasPrefix) {
myUri = contextSupport.translateNamespacePrefixToUri(this.prefix);
if (myUri == null) {
throw new UnresolvableException("Cannot resolve namespace prefix '"+this.prefix+"'");
}
}
else if (matchesAnyName) {
return true;
}
// If we map to a non-empty namespace and the node does not
// or vice-versa, fail-fast.
if (hasNamespace(myUri) != hasNamespace(nodeUri)) {
return false;
}
// To fail-fast, we check the equality of
// local-names first. Shorter strings compare
// quicker.
if (matchesAnyName || nodeName.equals(getLocalName())) {
return matchesNamespaceURIs(myUri, nodeUri);
}
return false;
}
/**
* Checks whether the URI represents a namespace.
*
* @param uri the URI to check
* @return true if non-null and non-empty
*/
private boolean hasNamespace(String uri) {
return (uri != null && uri.length() > 0);
}
/**
* Compares two namespace URIs, handling null.
*
* @param uri1 the first URI
* @param uri2 the second URI
* @return true if equal, where null==""
*/
protected boolean matchesNamespaceURIs(String uri1, String uri2) {
if (uri1 == uri2) {
return true;
}
if (uri1 == null) {
return (uri2.length() == 0);
}
if (uri2 == null) {
return (uri1.length() == 0);
}
return uri1.equals(uri2);
}
/**
* Returns a full information debugging string.
*
* @return a debugging string
*/
public String toString() {
String prefix = getPrefix();
String qName = "".equals(prefix) ? getLocalName() : getPrefix() + ":" + getLocalName();
return "[(DefaultNameStep): " + qName + "]";
}
}