/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.jxpath.ri.compiler;
import java.util.Arrays;
import org.apache.commons.jxpath.Function;
import org.apache.commons.jxpath.JXPathFunctionNotFoundException;
import org.apache.commons.jxpath.NodeSet;
import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.QName;
import org.apache.commons.jxpath.ri.axes.NodeSetContext;
/**
* Represents an element of the parse tree representing an extension function
* call.
*
* @author Dmitri Plotnikov
* @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
*/
public class ExtensionFunction extends Operation {
private QName functionName;
/**
* Create a new ExtensionFunction.
* @param functionName name of the function
* @param args Expression[] of function args
*/
public ExtensionFunction(QName functionName, Expression[] args) {
super(args);
this.functionName = functionName;
}
/**
* Get the function name
* @return QName
*/
public QName getFunctionName() {
return functionName;
}
/**
* An extension function gets the current context, therefore it MAY be
* context dependent.
* @return true
*/
public boolean computeContextDependent() {
return true;
}
public String toString() {
StringBuffer buffer = new StringBuffer();
buffer.append(functionName);
buffer.append('(');
Expression[] args = getArguments();
if (args != null) {
for (int i = 0; i < args.length; i++) {
if (i > 0) {
buffer.append(", ");
}
buffer.append(args[i]);
}
}
buffer.append(')');
return buffer.toString();
}
public Object compute(EvalContext context) {
return computeValue(context);
}
public Object computeValue(EvalContext context) {
Object[] parameters = null;
if (args != null) {
parameters = new Object[args.length];
for (int i = 0; i < args.length; i++) {
parameters[i] = convert(args[i].compute(context));
}
}
Function function =
context.getRootContext().getFunction(functionName, parameters);
if (function == null) {
throw new JXPathFunctionNotFoundException("No such function: "
+ functionName + Arrays.asList(parameters));
}
Object result = function.invoke(context, parameters);
return result instanceof NodeSet ? new NodeSetContext(context,
(NodeSet) result) : result;
}
/**
* Convert any incoming context to a value.
* @param object Object to convert
* @return context value or <code>object</code> unscathed.
*/
private Object convert(Object object) {
return object instanceof EvalContext ? ((EvalContext) object).getValue() : object;
}
}