/*
* Copyright 2002-2006 The Apache Software Foundation.
*
* Licensed 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.jexl.parser;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Map;
import org.apache.commons.jexl.JexlContext;
import org.apache.commons.jexl.util.Introspector;
import org.apache.commons.jexl.util.introspection.Info;
import org.apache.commons.jexl.util.introspection.VelMethod;
/**
* generalized size() function for all classes we can think of.
*
* @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
* @author <a href="hw@kremvax.net">Mark H. Wilkinson</a>
* @version $Id: ASTSizeFunction.java 398324 2006-04-30 12:20:24Z dion $
*/
public class ASTSizeFunction extends SimpleNode {
/**
* Create the node given an id.
*
* @param id node id.
*/
public ASTSizeFunction(int id) {
super(id);
}
/**
* Create a node with the given parser and id.
*
* @param p a parser.
* @param id node id.
*/
public ASTSizeFunction(Parser p, int id) {
super(p, id);
}
/** {@inheritDoc} */
public Object jjtAccept(ParserVisitor visitor, Object data) {
return visitor.visit(this, data);
}
/** {@inheritDoc} */
public Object value(JexlContext jc) throws Exception {
SimpleNode arg = (SimpleNode) jjtGetChild(0);
Object val = arg.value(jc);
if (val == null) {
throw new Exception("size() : null arg");
}
return new Integer(ASTSizeFunction.sizeOf(val));
}
/**
* Calculate the <code>size</code> of various types: Collection, Array, Map, String,
* and anything that has a int size() method.
*
* @param val the object to get the size of.
* @return the size of val
* @throws Exception if the size cannot be determined.
*/
public static int sizeOf(Object val) throws Exception {
if (val instanceof Collection) {
return ((Collection) val).size();
} else if (val.getClass().isArray()) {
return Array.getLength(val);
} else if (val instanceof Map) {
return ((Map) val).size();
} else if (val instanceof String) {
return ((String) val).length();
} else {
// check if there is a size method on the object that returns an
// integer
// and if so, just use it
Object[] params = new Object[0];
Info velInfo = new Info("", 1, 1);
VelMethod vm = Introspector.getUberspect().getMethod(val, "size", params, velInfo);
if (vm != null && vm.getReturnType() == Integer.TYPE) {
Integer result = (Integer) vm.invoke(val, params);
return result.intValue();
}
throw new Exception("size() : unknown type : " + val.getClass());
}
}
}