/*
* $Id: JaxpXPathExpressionEvaluator.java 20321 2010-11-24 15:21:24Z dfeist $
* --------------------------------------------------------------------------------------
* Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com
*
* The software in this package is published under the terms of the CPAL v1.0
* license, a copy of which has been included with this distribution in the
* LICENSE.txt file.
*/
package org.mule.module.xml.expression;
import org.mule.api.MuleContext;
import org.mule.api.MuleMessage;
import org.mule.api.MuleRuntimeException;
import org.mule.api.context.MuleContextAware;
import org.mule.api.context.notification.MuleContextNotificationListener;
import org.mule.api.expression.ExpressionEvaluator;
import org.mule.api.lifecycle.Disposable;
import org.mule.api.lifecycle.Initialisable;
import org.mule.api.lifecycle.InitialisationException;
import org.mule.api.registry.RegistrationException;
import org.mule.context.notification.MuleContextNotification;
import org.mule.module.xml.i18n.XmlMessages;
import org.mule.module.xml.stax.MapNamespaceContext;
import org.mule.module.xml.util.NamespaceManager;
import java.util.Map;
import java.util.WeakHashMap;
import javax.xml.namespace.QName;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.mule.transformer.types.DataTypeFactory;
import org.w3c.dom.Node;
/**
* Uses JAXP XPath processing to evaluate xpath expressions against Xml fragments and documents
* <p/>
* Note that the Jaxp Expression evaluator differs from the Mule XPATH evaluator slightly since you cna set the JaxP
* return type as a prefix to the expression i.e.
* <code>
* xpath2:[node]/foo/bar
* </code>
* <p/>
* Where the type can either be boolean, string, number, node or nodeset. iBeans will automatically convert numbers based on the
* return type as well as convert node to Document if required.
*/
public class JaxpXPathExpressionEvaluator implements ExpressionEvaluator, Initialisable, Disposable, MuleContextAware
{
private Map cache = new WeakHashMap(8);
private MuleContext muleContext;
private NamespaceManager namespaceManager;
private QName returnType = XPathConstants.STRING;
public JaxpXPathExpressionEvaluator()
{
}
public String getName()
{
return "xpath2";
}
public void setMuleContext(MuleContext context)
{
this.muleContext = context;
}
public void initialise() throws InitialisationException
{
try
{
/*
Workaround for standalone mode, when registry bootstrap order may be non-deterministic and lead
to failures on startup.
initialise() can't do any lookups as it will have spring create and init beans for things like
global endpoints, interfering with current lifecycle and leading to failure.
TODO AP/RM this will be solved by the @Inject annotation or phase, as discussed
RM*: Update: I'm hesistant to include support for @Inject since MUle isn't a DI container and
having this annotation (and associated @Named) sends a confusing message
*/
this.muleContext.registerListener(new MuleContextNotificationListener<MuleContextNotification>(){
public void onNotification(MuleContextNotification notification)
{
// CONTEXT_INITIALIZED fires too soon, before registry is inited, thus using this one
if (MuleContextNotification.CONTEXT_STARTING == notification.getAction())
{
try
{
namespaceManager = muleContext.getRegistry().lookupObject(NamespaceManager.class);
}
catch (RegistrationException e)
{
throw new RuntimeException(e);
}
}
}
});
}
catch (Throwable t)
{
throw new InitialisationException(t, this);
}
}
/**
* {@inheritDoc}
*/
public Object evaluate(String expression, MuleMessage message)
{
QName retType = returnType;
if (expression.startsWith("["))
{
int x = expression.indexOf("]");
if (x == -1)
{
throw new IllegalArgumentException("Expression is malformed: " + expression);
}
String type = expression.substring(1, x);
expression = expression.substring(x + 1);
if (type.equalsIgnoreCase("boolean"))
{
retType = XPathConstants.BOOLEAN;
}
else if (type.equalsIgnoreCase("string"))
{
retType = XPathConstants.STRING;
}
else if (type.equalsIgnoreCase("node"))
{
retType = XPathConstants.NODE;
}
else if (type.equalsIgnoreCase("nodeset"))
{
retType = XPathConstants.NODESET;
}
else if (type.equalsIgnoreCase("number"))
{
retType = XPathConstants.NUMBER;
}
else
{
throw new IllegalArgumentException("Result type not recognised: " + type + ". Use either boolean, string, number, node or nodeset.");
}
}
try
{
Node payload = (Node) message.getPayload(DataTypeFactory.create(Node.class));
XPathExpression xpath = getXPath(expression);
return xpath.evaluate(payload, retType);
}
catch (Exception e)
{
throw new MuleRuntimeException(XmlMessages.failedToProcessXPath(expression), e);
}
}
/**
* {@inheritDoc}
*/
public final void setName(String name)
{
throw new UnsupportedOperationException("setName");
}
protected XPathExpression getXPath(String expression) throws XPathExpressionException
{
XPathExpression xpath = (XPathExpression) cache.get(expression + getClass().getName());
if (xpath == null)
{
xpath = createXPath(expression);
cache.put(expression + getClass().getName(), xpath);
}
return xpath;
}
protected XPathExpression createXPath(String expression) throws XPathExpressionException
{
XPath xp = XPathFactory.newInstance().newXPath();
if (getNamespaceManager() != null)
{
xp.setNamespaceContext(new MapNamespaceContext(getNamespaceManager().getNamespaces()));
}
return xp.compile(expression);
}
/**
* A lifecycle method where implementor should free up any resources. If an
* exception is thrown it should just be logged and processing should continue.
* This method should not throw Runtime exceptions.
*/
public void dispose()
{
cache.clear();
}
public NamespaceManager getNamespaceManager()
{
return namespaceManager;
}
public void setNamespaceManager(NamespaceManager namespaceManager)
{
this.namespaceManager = namespaceManager;
}
public MuleContext getMuleContext()
{
return muleContext;
}
public QName getReturnType()
{
return returnType;
}
public void setReturnType(QName returnType)
{
this.returnType = returnType;
}
}