001    // Copyright 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    // http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.internal.plastic;
016    
017    import org.apache.tapestry5.plastic.MethodHandle;
018    import org.apache.tapestry5.plastic.MethodInvocationResult;
019    
020    public class MethodHandleImpl implements MethodHandle
021    {
022        private final String className, methodDescription;
023    
024        private final int methodIndex;
025    
026        protected volatile PlasticClassHandleShim shim;
027    
028        public MethodHandleImpl(String className, String methodDescription, int methodIndex)
029        {
030            this.className = className;
031            this.methodDescription = methodDescription;
032            this.methodIndex = methodIndex;
033        }
034    
035        public String toString()
036        {
037            return String.format("MethodHandle[%s %s]", className, methodDescription);
038        }
039    
040        public MethodInvocationResult invoke(Object instance, Object... arguments)
041        {
042    
043            if (instance == null)
044                throw new NullPointerException(String.format(
045                        "Unable to invoke method %s of class %s, as provided instance is null.", methodDescription,
046                        className));
047    
048            return shim.invoke(instance, methodIndex, arguments);
049        }
050    
051    }