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/* Generated by Together */
package com.hp.hpl.sparta.xpath;
import java.io.*;
import java.util.*;
/** The root of the parse tree for an XPath expression. This is a
* participant in the Visitor Pattern [Gamma et al, #331]. You create
* an XPath object (which parses an XPath expression into a parse
* tree), create a Vistor object, and pass the visitor to the
* XPath.accept method.
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: 2003/07/18 00:01:42 $ $Revision: 1.10 $
@author Eamonn O'Brien-Strain
*/
public class XPath {
static private final int ASSERTION = 0;
/** Create an XPath from some steps. steps.lenght must be >= 1 */
private XPath(boolean isAbsolute, Step[] steps) {
for (int i = 0; i < steps.length; ++i)
steps_.addElement(steps[i]);
absolute_ = isAbsolute;
string_ = null;
}
/** Parse an XPath from a string. */
private XPath(String s) throws XPathException /*, IOException*/{
//StringReader not supported in J2ME
this(s, new InputStreamReader(new ByteArrayInputStream(s.getBytes())));
}
/** Parse an XPath from a character stream. */
private XPath(String s, Reader reader) throws XPathException {
try {
string_ = s;
SimpleStreamTokenizer toks = new SimpleStreamTokenizer(reader);
toks.ordinaryChar('/'); // '/' is not a comment
toks.ordinaryChar('.'); // '.' is not a part of a number
toks.wordChars(':', ':'); //Allow namespaces
toks.wordChars('_', '_'); //Allow namespaces
boolean multiLevel;
if (toks.nextToken() == '/') {
absolute_ = true;
if (toks.nextToken() == '/') {
multiLevel = true;
toks.nextToken();
} else
multiLevel = false;
} else {
absolute_ = false;
multiLevel = false;
}
//current token is first token of node_test production
steps_.push(new Step(this, multiLevel, toks));
//current token is token after last token of step production
while (toks.ttype == '/') {
if (toks.nextToken() == '/') {
multiLevel = true;
toks.nextToken();
} else
multiLevel = false;
//current token is first token of node_test production
steps_.push(new Step(this, multiLevel, toks));
//current token is token after last token of step production
}
if (toks.ttype != SimpleStreamTokenizer.TT_EOF)
throw new XPathException(this, "at end of XPATH expression", toks, "end of expression");
} catch (IOException e) {
throw new XPathException(this, e);
}
if (ASSERTION >= 2)
if (!toString().equals(generateString())) throw new Error("Postcondition failed");
}
public String toString() {
if (string_ == null) string_ = generateString();
return string_;
}
private String generateString() {
StringBuffer result = new StringBuffer();
boolean first = true;
for (Enumeration i = steps_.elements(); i.hasMoreElements();) {
Step step = (Step) i.nextElement();
if (!first || absolute_) {
result.append('/');
if (step.isMultiLevel()) result.append('/');
}
result.append(step.toString());
first = false;
}
return result.toString();
}
/** Does this path begin with a '/' or '//' ? */
public boolean isAbsolute() {
return absolute_;
}
/** Does xpath evaluate to a string values (attribute values or
text() nodes)*/
public boolean isStringValue() {
Step lastStep = (Step) steps_.peek();
return lastStep.isStringValue();
}
public Enumeration getSteps() {
return steps_.elements();
}
/** Return the attribute name in a trailing [@attrName] predicate.
* For example if the Xpath expression was "/a/b[@p='pp']/c[@q]"
* then the indexing attribute name would be "q"*/
public String getIndexingAttrName() throws XPathException {
Step step = (Step) steps_.peek();
BooleanExpr predicate = step.getPredicate();
if (!(predicate instanceof AttrExistsExpr))
throw new XPathException(this,
"has no indexing attribute name (must end with predicate of the form [@attrName]");
return ((AttrExistsExpr) predicate).getAttrName();
}
/** Return the attribute name in a trailing [@attrName='attrValue'] predicate
* or null if it someother type of predicate..
* For example if the Xpath expression was "/a/b[@p='pp']/c[@q='qqq']"
* then the indexing attribute name would be "q"*/
public String getIndexingAttrNameOfEquals() throws XPathException {
Step step = (Step) steps_.peek();
BooleanExpr predicate = step.getPredicate();
if (predicate instanceof AttrEqualsExpr)
return ((AttrEqualsExpr) predicate).getAttrName();
else
return null;
}
/** A one-level clone in which the steps list is cloned but not the steps objects themselves.
* It is OK for different XPaths to share Steps because they are immutable. */
public Object clone() {
Step[] steps = new Step[steps_.size()];
Enumeration step = steps_.elements();
for (int i = 0; i < steps.length; ++i)
steps[i] = (Step) step.nextElement();
return new XPath(absolute_, steps);
}
/**
*@link aggregation
* @associates <{Step}>
*/
private Stack steps_ = new Stack();
private/*final (JDK11 problems)*/
boolean absolute_;
private String string_;
////////////////////////////////////////////////////////////////
/** Return the xpath parse-tree object for this expression.
* This may be either a newly
* created object or a cached copy. */
static public XPath get(String xpathString) throws XPathException //, IOException
{
synchronized (cache_) {
XPath result = (XPath) cache_.get(xpathString);
if (result == null) {
result = new XPath(xpathString);
cache_.put(xpathString, result);
}
return result;
}
}
/** Create an XPath from some steps.
The value of steps.length must be >= 1 */
static public XPath get(boolean isAbsolute, Step[] steps) {
XPath created = new XPath(isAbsolute, steps);
String xpathString = created.toString();
synchronized (cache_) {
XPath inCache = (XPath) cache_.get(xpathString);
if (inCache == null) {
cache_.put(xpathString, created);
return created;
} else
return inCache;
}
}
/** Convenience function equivalent to get(xpathString).isStringValue() */
static public boolean isStringValue(String xpathString) throws XPathException, IOException {
return get(xpathString).isStringValue();
}
/** @associates XPath
* Warning grows without bound, no eviction.
* TODO: make LRU
*/
static private Hashtable cache_ = new Hashtable();
}
// $Log: XPath.java,v $
// Revision 1.10 2003/07/18 00:01:42 eobrain
// Make compatiblie with J2ME. For example do not use "new"
// java.util classes.
//
// Revision 1.9 2003/06/19 20:29:04 eobrain
// Add monitoring (in debug mode) to detect when indexing could optimize.
//
// Revision 1.8 2003/05/12 20:08:10 eobrain
// Inconsequential code change to avoid eclipse warning.
//
// Revision 1.7 2003/03/21 00:21:25 eobrain
// Allow underscores in attribute names.
//
// Revision 1.6 2003/01/27 23:30:58 yuhongx
// Replaced Hashtable with HashMap.
//
// Revision 1.5 2003/01/09 01:17:14 yuhongx
// Use JDK1.1 API to make code work with PersonalJava (use addElement()).
//
// Revision 1.4 2002/12/13 22:42:22 eobrain
// Fix javadoc.
//
// Revision 1.3 2002/12/13 18:09:34 eobrain
// Create XPath from a sequence of steps.
//
// Revision 1.2 2002/12/06 23:41:49 eobrain
// Add toString() which returns the original XPath.
//
// Revision 1.1.1.1 2002/08/19 05:04:02 eobrain
// import from HP Labs internal CVS
//
// Revision 1.9 2002/08/18 23:39:27 eob
// Add copyright and other formatting and commenting in preparation for
// release to SourceForge.
//
// Revision 1.8 2002/08/15 05:11:35 eob
// getIndexingAttrName
//
// Revision 1.7 2002/06/21 00:35:19 eob
// Make work with old JDK 1.1.*
//
// Revision 1.6 2002/06/04 05:27:08 eob
// Simplify use of visitor pattern to make code easier to understand.
//
// Revision 1.5 2002/05/23 21:14:51 eob
// Better error reporting.
//
// Revision 1.4 2002/05/10 19:42:48 eob
// Add static isStringValue
//
// Revision 1.3 2002/03/26 05:31:49 eob
// Making contructor private. Adding static factory method to manage
// cache of XPath objects.
//
// Revision 1.2 2002/02/04 22:12:59 eob
// Add boolean property to test whether this xpath returns a string.
//
// Revision 1.1 2002/02/01 01:59:09 eob
// initial
