001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.jxpath.functions;
018
019 import java.lang.reflect.InvocationTargetException;
020 import java.lang.reflect.Method;
021 import java.lang.reflect.Modifier;
022
023 import org.apache.commons.jxpath.ExpressionContext;
024 import org.apache.commons.jxpath.Function;
025 import org.apache.commons.jxpath.JXPathInvalidAccessException;
026 import org.apache.commons.jxpath.util.TypeUtils;
027 import org.apache.commons.jxpath.util.ValueUtils;
028
029 /**
030 * An XPath extension function implemented as an individual Java method.
031 *
032 * @author Dmitri Plotnikov
033 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
034 */
035 public class MethodFunction implements Function {
036
037 private Method method;
038 private static final Object[] EMPTY_ARRAY = new Object[0];
039
040 /**
041 * Create a new MethodFunction.
042 * @param method implementing Method
043 */
044 public MethodFunction(Method method) {
045 this.method = ValueUtils.getAccessibleMethod(method);
046 }
047
048 public Object invoke(ExpressionContext context, Object[] parameters) {
049 try {
050 Object target;
051 Object[] args;
052 if (Modifier.isStatic(method.getModifiers())) {
053 target = null;
054 if (parameters == null) {
055 parameters = EMPTY_ARRAY;
056 }
057 int pi = 0;
058 Class[] types = method.getParameterTypes();
059 if (types.length >= 1
060 && ExpressionContext.class.isAssignableFrom(types[0])) {
061 pi = 1;
062 }
063 args = new Object[parameters.length + pi];
064 if (pi == 1) {
065 args[0] = context;
066 }
067 for (int i = 0; i < parameters.length; i++) {
068 args[i + pi] =
069 TypeUtils.convert(parameters[i], types[i + pi]);
070 }
071 }
072 else {
073 int pi = 0;
074 Class[] types = method.getParameterTypes();
075 if (types.length >= 1
076 && ExpressionContext.class.isAssignableFrom(types[0])) {
077 pi = 1;
078 }
079 target =
080 TypeUtils.convert(
081 parameters[0],
082 method.getDeclaringClass());
083 args = new Object[parameters.length - 1 + pi];
084 if (pi == 1) {
085 args[0] = context;
086 }
087 for (int i = 1; i < parameters.length; i++) {
088 args[pi + i - 1] =
089 TypeUtils.convert(parameters[i], types[i + pi - 1]);
090 }
091 }
092
093 return method.invoke(target, args);
094 }
095 catch (Throwable ex) {
096 if (ex instanceof InvocationTargetException) {
097 ex = ((InvocationTargetException) ex).getTargetException();
098 }
099 throw new JXPathInvalidAccessException("Cannot invoke " + method,
100 ex);
101 }
102 }
103
104 public String toString() {
105 return method.toString();
106 }
107 }