/*--
$Id: JaxenXPath.java,v 1.19 2004/09/03 07:27:39 jhunter Exp $
Copyright (C) 2000-2004 Jason Hunter & Brett McLaughlin.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions, and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions, and the disclaimer that follows
these conditions in the documentation and/or other materials
provided with the distribution.
3. The name "JDOM" must not be used to endorse or promote products
derived from this software without prior written permission. For
written permission, please contact <request_AT_jdom_DOT_org>.
4. Products derived from this software may not be called "JDOM", nor
may "JDOM" appear in their name, without prior written permission
from the JDOM Project Management <request_AT_jdom_DOT_org>.
In addition, we request (but do not require) that you include in the
end-user documentation provided with the redistribution and/or in the
software itself an acknowledgement equivalent to the following:
"This product includes software developed by the
JDOM Project (http://www.jdom.org/)."
Alternatively, the acknowledgment may be graphical using the logos
available at http://www.jdom.org/images/logos.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE JDOM AUTHORS OR THE PROJECT
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
This software consists of voluntary contributions made by many
individuals on behalf of the JDOM Project and was originally
created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
Brett McLaughlin <brett_AT_jdom_DOT_org>. For more information
on the JDOM Project, please see <http://www.jdom.org/>.
*/
package org.jdom.xpath;
import java.util.*;
import org.jaxen.*;
import org.jaxen.jdom.*;
import org.jdom.*;
/**
* A non-public concrete XPath implementation for Jaxen.
*
* @version $Revision: 1.19 $, $Date: 2004/09/03 07:27:39 $
* @author Laurent Bihanic
*/
class JaxenXPath extends XPath { // package protected
private static final String CVS_ID =
"@(#) $RCSfile: JaxenXPath.java,v $ $Revision: 1.19 $ $Date: 2004/09/03 07:27:39 $ $Name: jdom_1_0 $";
/**
* The compiled XPath object to select nodes. This attribute can
* not be made final as it needs to be set upon object
* deserialization.
*/
private transient JDOMXPath xPath;
/**
* The current context for XPath expression evaluation.
*/
private Object currentContext;
/**
* Creates a new XPath wrapper object, compiling the specified
* XPath expression.
*
* @param expr the XPath expression to wrap.
*
* @throws JDOMException if the XPath expression is invalid.
*/
public JaxenXPath(String expr) throws JDOMException {
setXPath(expr);
}
/**
* Evaluates the wrapped XPath expression and returns the list
* of selected items.
*
* @param context the node to use as context for evaluating
* the XPath expression.
*
* @return the list of selected items, which may be of types: {@link Element},
* {@link Attribute}, {@link Text}, {@link CDATA},
* {@link Comment}, {@link ProcessingInstruction}, Boolean,
* Double, or String.
*
* @throws JDOMException if the evaluation of the XPath
* expression on the specified context
* failed.
*/
public List selectNodes(Object context) throws JDOMException {
try {
currentContext = context;
return xPath.selectNodes(context);
}
catch (JaxenException ex1) {
throw new JDOMException("XPath error while evaluating \"" +
xPath.toString() + "\": " + ex1.getMessage(), ex1);
}
finally {
currentContext = null;
}
}
/**
* Evaluates the wrapped XPath expression and returns the first
* entry in the list of selected nodes (or atomics).
*
* @param context the node to use as context for evaluating
* the XPath expression.
*
* @return the first selected item, which may be of types: {@link Element},
* {@link Attribute}, {@link Text}, {@link CDATA},
* {@link Comment}, {@link ProcessingInstruction}, Boolean,
* Double, String, or <code>null</code> if no item was selected.
*
* @throws JDOMException if the evaluation of the XPath
* expression on the specified context
* failed.
*/
public Object selectSingleNode(Object context) throws JDOMException {
try {
currentContext = context;
return xPath.selectSingleNode(context);
}
catch (JaxenException ex1) {
throw new JDOMException("XPath error while evaluating \"" +
xPath.toString() + "\": " + ex1.getMessage(), ex1);
}
finally {
currentContext = null;
}
}
/**
* Returns the string value of the first node selected by applying
* the wrapped XPath expression to the given context.
*
* @param context the element to use as context for evaluating
* the XPath expression.
*
* @return the string value of the first node selected by applying
* the wrapped XPath expression to the given context.
*
* @throws JDOMException if the XPath expression is invalid or
* its evaluation on the specified context
* failed.
*/
public String valueOf(Object context) throws JDOMException {
try {
currentContext = context;
return xPath.stringValueOf(context);
}
catch (JaxenException ex1) {
throw new JDOMException("XPath error while evaluating \"" +
xPath.toString() + "\": " + ex1.getMessage(), ex1);
}
finally {
currentContext = null;
}
}
/**
* Returns the number value of the first item selected by applying
* the wrapped XPath expression to the given context.
*
* @param context the element to use as context for evaluating
* the XPath expression.
*
* @return the number value of the first item selected by applying
* the wrapped XPath expression to the given context,
* <code>null</code> if no node was selected or the
* special value {@link java.lang.Double#NaN}
* (Not-a-Number) if the selected value can not be
* converted into a number value.
*
* @throws JDOMException if the XPath expression is invalid or
* its evaluation on the specified context
* failed.
*/
public Number numberValueOf(Object context) throws JDOMException {
try {
currentContext = context;
return xPath.numberValueOf(context);
}
catch (JaxenException ex1) {
throw new JDOMException("XPath error while evaluating \"" +
xPath.toString() + "\": " + ex1.getMessage(), ex1);
}
finally {
currentContext = null;
}
}
/**
* Defines an XPath variable and sets its value.
*
* @param name the variable name.
* @param value the variable value.
*
* @throws IllegalArgumentException if <code>name</code> is not
* a valid XPath variable name
* or if the value type is not
* supported by the underlying
* implementation
*/
public void setVariable(String name, Object value)
throws IllegalArgumentException {
Object o = xPath.getVariableContext();
if (o instanceof SimpleVariableContext) {
((SimpleVariableContext)o).setVariableValue(null, name, value);
}
}
/**
* Adds a namespace definition to the list of namespaces known of
* this XPath expression.
* <p>
* <strong>Note</strong>: In XPath, there is no such thing as a
* 'default namespace'. The empty prefix <b>always</b> resolves
* to the empty namespace URI.</p>
*
* @param namespace the namespace.
*/
public void addNamespace(Namespace namespace) {
try {
xPath.addNamespace(namespace.getPrefix(), namespace.getURI());
}
catch (JaxenException ex1) { /* Can't happen here. */ }
}
/**
* Returns the wrapped XPath expression as a string.
*
* @return the wrapped XPath expression as a string.
*/
public String getXPath() {
return (xPath.toString());
}
/**
* Compiles and sets the XPath expression wrapped by this object.
*
* @param expr the XPath expression to wrap.
*
* @throws JDOMException if the XPath expression is invalid.
*/
private void setXPath(String expr) throws JDOMException {
try {
xPath = new JDOMXPath(expr);
xPath.setNamespaceContext(new NSContext());
}
catch (Exception ex1) {
throw new JDOMException(
"Invalid XPath expression: \"" + expr + "\"", ex1);
}
}
public String toString() {
return (xPath.toString());
}
public boolean equals(Object o) {
if (o instanceof JaxenXPath) {
JaxenXPath x = (JaxenXPath)o;
return (super.equals(o) &&
xPath.toString().equals(x.xPath.toString()));
}
return false;
}
public int hashCode() {
return xPath.hashCode();
}
private class NSContext extends SimpleNamespaceContext {
public NSContext() {
super();
}
/**
* <i>[Jaxen NamespaceContext interface support]</i> Translates
* the provided namespace prefix into the matching bound
* namespace URI.
*
* @param prefix the namespace prefix to resolve.
*
* @return the namespace URI matching the prefix.
*/
public String translateNamespacePrefixToUri(String prefix) {
if ((prefix == null) || (prefix.length() == 0)) {
return null;
}
String uri = super.translateNamespacePrefixToUri(prefix);
if (uri == null) {
Object ctx = currentContext;
if (ctx != null) {
Element elt = null;
// Get closer element node
if (ctx instanceof Element) {
elt = (Element)ctx;
} else if (ctx instanceof Attribute) {
elt = ((Attribute)ctx).getParent();
} else if (ctx instanceof Content) {
elt = ((Content) ctx).getParentElement();
} else if (ctx instanceof Document) {
elt = ((Document)ctx).getRootElement();
}
if (elt != null) {
Namespace ns = elt.getNamespace(prefix);
if (ns != null) {
uri = ns.getURI();
}
}
}
}
return uri;
}
}
}