com.hp.hpl.sparta.XPathVisitor Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of pinyin4j Show documentation
Show all versions of pinyin4j Show documentation
Support Chinese character (both Simplified and Tranditional) to most popular Pinyin systems, including Hanyu Pinyin, Tongyong Pinyin, Wade-Giles, MPS2, Yale and Gwoyeu Romatzyh. Support multiple pronounciations and customized output.
The newest version!
package com.hp.hpl.sparta;
import com.hp.hpl.sparta.xpath.*;
import java.io.IOException;
import java.util.*;
/**
* Visitor that evaluates an xpath expression relative to a context
* node by walking over the parse tree of the expression.
Copyright (C) 2002 Hewlett-Packard Company.
This file is part of Sparta, an XML Parser, DOM, and XPath library.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU
Lesser General Public License as published by the Free Software
Foundation; either version 2.1 of the License, or (at your option)
any later version. This library is distributed in the hope that it
will be useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.
@version $Date: 2003/08/11 18:48:39 $ $Revision: 1.9 $
@author Eamonn O'Brien-Strain
* @stereotype visitor */
class XPathVisitor implements Visitor {
/** Evaluate a relative xpath expression relative to a context
* element by walking over the parse tree of th expression. */
private XPathVisitor(XPath xpath, Node context) throws XPathException {
xpath_ = xpath;
contextNode_ = context;
nodelistFiltered_ = new Vector(1);
nodelistFiltered_.addElement(contextNode_);
for (Enumeration i = xpath.getSteps(); i.hasMoreElements();) {
Step step = (Step) i.nextElement();
multiLevel_ = step.isMultiLevel();
nodesetIterator_ = null;
step.getNodeTest().accept(this);
nodesetIterator_ = nodelistRaw_.iterator();
nodelistFiltered_.removeAllElements();
BooleanExpr predicate = step.getPredicate();
while (nodesetIterator_.hasMoreElements()) {
node_ = nodesetIterator_.nextElement();
predicate.accept(this);
Boolean expr = exprStack_.pop();
if (expr.booleanValue()) nodelistFiltered_.addElement(node_);
}
}
}
/** Evaluate a relative xpath expression relative to a context
* element by walking over the parse tree of th expression. */
public XPathVisitor(Element context, XPath xpath) throws XPathException {
this(xpath, context);
if (xpath.isAbsolute())
throw new XPathException(xpath, "Cannot use element as context node for absolute xpath");
}
/** Evaluate an absolute xpath expression in a document by walking
over the parse tree of th expression. */
public XPathVisitor(Document context, XPath xpath) throws XPathException {
this(xpath, context);
}
public void visit(ThisNodeTest a) {
nodelistRaw_.removeAllElements();
nodelistRaw_.add(contextNode_, 1);
}
/** @throws XPathException if ".." applied to node with no parent. */
public void visit(ParentNodeTest a) throws XPathException {
nodelistRaw_.removeAllElements();
Node parent = contextNode_.getParentNode();
if (parent == null)
throw new XPathException(xpath_, "Illegal attempt to apply \"..\" to node with no parent.");
nodelistRaw_.add(parent, 1);
}
public void visit(AllElementTest a) {
Vector oldNodeList = nodelistFiltered_;
nodelistRaw_.removeAllElements();
for (Enumeration i = oldNodeList.elements(); i.hasMoreElements();) {
Object node = i.nextElement();
if (node instanceof Element)
accumulateElements((Element) node);
else if (node instanceof Document) accumulateElements((Document) node);
}
}
private void accumulateElements(Document doc) {
Element child = doc.getDocumentElement();
nodelistRaw_.add(child, 1);
if (multiLevel_) accumulateElements(child); //recursive call
}
private void accumulateElements(Element element) {
int position = 0;
for (Node n = element.getFirstChild(); n != null; n = n.getNextSibling()) {
if (n instanceof Element) {
nodelistRaw_.add(n, ++position);
if (multiLevel_) accumulateElements((Element) n); //recursive call
}
}
}
public void visit(TextTest a) {
Vector oldNodeList = nodelistFiltered_;
nodelistRaw_.removeAllElements();
for (Enumeration i = oldNodeList.elements(); i.hasMoreElements();) {
Object node = i.nextElement();
if (node instanceof Element) {
Element element = (Element) node;
for (Node n = element.getFirstChild(); n != null; n = n.getNextSibling())
if (n instanceof Text) nodelistRaw_.add(((Text) n).getData());
}
}
}
public void visit(ElementTest test) {
String tagName = test.getTagName();
Vector oldNodeList = nodelistFiltered_;
int n = oldNodeList.size();
nodelistRaw_.removeAllElements();
for (int i = 0; i < n; ++i) {
Object node = oldNodeList.elementAt(i);
if (node instanceof Element)
accumulateMatchingElements((Element) node, tagName);
else if (node instanceof Document) accumulateMatchingElements((Document) node, tagName);
}
}
private void accumulateMatchingElements(Document document, String tagName) {
Element child = document.getDocumentElement();
if (child == null) return; //no document element
if (child.getTagName() == tagName) //both strings interned
nodelistRaw_.add(child, 1);
if (multiLevel_) accumulateMatchingElements(child, tagName); //recursive call
}
private void accumulateMatchingElements(Element element, String tagName) {
int position = 0;
for (Node n = element.getFirstChild(); n != null; n = n.getNextSibling()) {
if (n instanceof Element) {
Element child = (Element) n;
if (child.getTagName() == tagName) //both strings interned
nodelistRaw_.add(child, ++position);
if (multiLevel_) accumulateMatchingElements(child, tagName); //recursion
}
}
}
public void visit(AttrTest test) {
Vector oldNodeList = nodelistFiltered_;
nodelistRaw_.removeAllElements();
for (Enumeration i = oldNodeList.elements(); i.hasMoreElements();) {
Node node = (Node) i.nextElement();
if (node instanceof Element) {
Element element = (Element) node;
String attr = element.getAttribute(test.getAttrName());
if (attr != null) nodelistRaw_.add(attr);
}
}
}
static private final Boolean TRUE = new Boolean(true);
static private final Boolean FALSE = new Boolean(false);
public void visit(TrueExpr a) {
exprStack_.push(TRUE);
}
public void visit(AttrExistsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
String attrValue = element.getAttribute(a.getAttrName());
boolean result = attrValue != null && attrValue.length() > 0;
exprStack_.push(result ? TRUE : FALSE);
}
public void visit(AttrEqualsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
String attrValue = element.getAttribute(a.getAttrName());
boolean result = a.getAttrValue().equals(attrValue);
exprStack_.push(result ? TRUE : FALSE);
}
public void visit(AttrNotEqualsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
String attrValue = element.getAttribute(a.getAttrName());
boolean result = !a.getAttrValue().equals(attrValue);
exprStack_.push(result ? TRUE : FALSE);
}
public void visit(AttrLessExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
// Use jdk1.1 API to make the code work with PersonalJava.
// double attrValue = Double.parseDouble( element.getAttribute( a.getAttrName() ) );
long attrValue = Long.parseLong(element.getAttribute(a.getAttrName()));
boolean result = attrValue < a.getAttrValue();
exprStack_.push(result ? TRUE : FALSE);
}
public void visit(AttrGreaterExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
// Use jdk1.1 API to make the code work with PersonalJava.
// double attrValue = Double.parseDouble( element.getAttribute( a.getAttrName() ) );
long attrValue = Long.parseLong(element.getAttribute(a.getAttrName()));
boolean result = attrValue > a.getAttrValue();
exprStack_.push(result ? TRUE : FALSE);
}
public void visit(TextExistsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
for (Node i = element.getFirstChild(); i != null; i = i.getNextSibling()) {
if (i instanceof Text) {
exprStack_.push(TRUE);
return;
}
}
exprStack_.push(FALSE);
}
public void visit(TextEqualsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
for (Node i = element.getFirstChild(); i != null; i = i.getNextSibling()) {
if (i instanceof Text) {
Text text = (Text) i;
if (text.getData().equals(a.getValue())) {
exprStack_.push(TRUE);
return;
}
}
}
exprStack_.push(FALSE);
}
public void visit(TextNotEqualsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test attribute of document");
Element element = (Element) node_;
for (Node i = element.getFirstChild(); i != null; i = i.getNextSibling()) {
if (i instanceof Text) {
Text text = (Text) i;
if (!text.getData().equals(a.getValue())) {
exprStack_.push(TRUE);
return;
}
}
}
exprStack_.push(FALSE);
}
public void visit(PositionEqualsExpr a) throws XPathException {
if (!(node_ instanceof Element))
throw new XPathException(xpath_, "Cannot test position of document");
Element element = (Element) node_;
boolean result = (nodelistRaw_.position(element) == a.getPosition());
exprStack_.push(result ? TRUE : FALSE);
}
/** Get all the elements or strings that match the xpath expression. */
public Enumeration getResultEnumeration() {
return nodelistFiltered_.elements();
}
/** Get the first element that match the xpath expression, or null. */
public Element getFirstResultElement() {
return nodelistFiltered_.size() == 0 ? null : (Element) nodelistFiltered_.elementAt(0);
}
/** Get the first string that match the xpath expression, or null. */
public String getFirstResultString() {
return nodelistFiltered_.size() == 0 ? null : (String) nodelistFiltered_.elementAt(0)
.toString();
}
/*
static private class BooleanStack extends LinkedList{
void push(Boolean b){
addLast(b);
}
Boolean pop(){
return (Boolean)removeLast();
}
}
*/
/** Profiling found this to be very heavily used so do not use java.util.LinkedList */
static private class BooleanStack {
private Item top_ = null;
static private class Item {
Item(Boolean b, Item p) {
bool = b;
prev = p;
}
final Boolean bool;
final Item prev;
}
void push(Boolean b) {
top_ = new Item(b, top_);
}
Boolean pop() {
Boolean result = top_.bool;
top_ = top_.prev;
return result;
}
}
/** @associates Node. */
private final NodeListWithPosition nodelistRaw_ = new NodeListWithPosition();
private Vector nodelistFiltered_ = new Vector();
private Enumeration nodesetIterator_ = null;
private Object node_ = null; //String or Element
private final BooleanStack exprStack_ = new BooleanStack();
/**
* @label context
*/
private/*final (JDK11 problems)*/
Node contextNode_;
private boolean multiLevel_;
private/*final (JDK11 problems)*/
XPath xpath_;
}
/** A list of nodes, together with the positions in their context of
each node. */
class NodeListWithPosition {
Enumeration iterator() {
return vector_.elements();
}
void removeAllElements() {
vector_.removeAllElements();
positions_.clear();
}
void add(String string) {
vector_.addElement(string);
}
static private final Integer ONE = new Integer(1);
static private final Integer TWO = new Integer(2);
static private final Integer THREE = new Integer(3);
static private final Integer FOUR = new Integer(4);
static private final Integer FIVE = new Integer(5);
static private final Integer SIX = new Integer(6);
static private final Integer SEVEN = new Integer(7);
static private final Integer EIGHT = new Integer(8);
static private final Integer NINE = new Integer(9);
static private final Integer TEN = new Integer(10);
static private Integer identity(Node node) {
return new Integer(System.identityHashCode(node));
}
void add(Node node, int position) {
//Profiling shows thisto be the most heavily used method in Sparta so
//optimize the crap out of it.
vector_.addElement(node);
//Avoid creating new integer objects for common cases
Integer posn;
switch (position) {
case 1:
posn = ONE;
break;
case 2:
posn = TWO;
break;
case 3:
posn = THREE;
break;
case 4:
posn = FOUR;
break;
case 5:
posn = FIVE;
break;
case 6:
posn = SIX;
break;
case 7:
posn = SEVEN;
break;
case 8:
posn = EIGHT;
break;
case 9:
posn = NINE;
break;
case 10:
posn = TEN;
break;
default:
posn = new Integer(position);
break;
}
positions_.put(identity(node), posn);
}
int position(Node node) {
return ((Integer) positions_.get(identity(node))).intValue();
}
public String toString() {
try {
StringBuffer y = new StringBuffer("{ ");
for (Enumeration i = vector_.elements(); i.hasMoreElements();) {
Object e = i.nextElement();
if (e instanceof String)
y.append("String(" + e + ") ");
else {
Node n = (Node) e;
y.append("Node(" + n.toXml() + ")[" + positions_.get(identity(n)) + "] ");
}
}
y.append("}");
return y.toString();
} catch (IOException e) {
return e.toString();
}
}
private final Vector vector_ = new Vector();
private Hashtable positions_ = new Hashtable();
}
// $Log: XPathVisitor.java,v $
// Revision 1.9 2003/08/11 18:48:39 eobrain
// Fix bug in xpath tag[n] when identical elements.
//
// Revision 1.8 2003/07/17 23:58:40 eobrain
// Make compatiblie with J2ME. For example do not use "new"
// java.util classes.
//
// Revision 1.7 2003/05/12 20:06:14 eobrain
// Performance improvements: optimize code in areas that profiling revealed to be bottlenecks.
//
// Revision 1.6 2003/01/27 23:30:58 yuhongx
// Replaced Hashtable with HashMap.
//
// Revision 1.5 2003/01/09 01:10:50 yuhongx
// Use JDK1.1 API to make the code work with PersonalJava.
//
// Revision 1.4 2002/12/05 04:35:39 eobrain
// Add support for greater than and less than in predicates.
//
// Revision 1.3 2002/10/30 16:28:46 eobrain
// Feature request [ 630127 ] Support /a/b[text()='foo']
// http://sourceforge.net/projects/sparta-xml/
//
// Revision 1.2 2002/09/18 05:29:04 eobrain
// Support xpath predicates of the form [1], [2], ...
//
// Revision 1.1.1.1 2002/08/19 05:03:53 eobrain
// import from HP Labs internal CVS
//
// Revision 1.11 2002/08/18 04:47:47 eob
// Make class package-private so as not to clutter up the javadoc.
//
// Revision 1.10 2002/06/21 00:28:33 eob
// Make work with old JDK 1.1.*
//
// Revision 1.9 2002/06/14 19:34:50 eob
// Add handling of "text()" in XPath expressions.
//
// Revision 1.8 2002/06/04 05:29:28 eob
// Simplify use of visitor pattern to make code easier to understand.
// Fix bug when predicate in middle of XPath.
//
// Revision 1.7 2002/05/23 21:18:52 eob
// Better error reporting.
//
// Revision 1.6 2002/05/10 21:39:28 eob
// Allow documents to take relative xpaths.
//
// Revision 1.5 2002/03/26 01:49:53 eob
// Return different results depending on type. Return first result.
//
// Revision 1.4 2002/03/21 23:54:36 eob
// Fix handling of .. when no parent.
//
// Revision 1.3 2002/02/14 02:21:45 eob
// Handle attribute XPaths.
//
// Revision 1.2 2002/02/04 22:09:44 eob
// add visit(AttrTest)
//
// Revision 1.1 2002/02/01 22:46:12 eob
// initial