OverrideMethod.java revision f013e1afd1e68af5e3b868c26a653bbfb39538f8
1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package com.android.tools.layoutlib.create; 18 19import java.util.HashMap; 20 21/** 22 * Allows stub methods from LayoutLib to be overriden at runtime. 23 */ 24public final class OverrideMethod { 25 26 /** 27 * Interface to allow a method invocation to be listend upon. 28 */ 29 public interface MethodListener { 30 /** 31 * A stub method is being invoked. 32 * <p/> 33 * Known limitation: caller arguments are not available. Return value cannot be set. 34 * 35 * @param signature The signature of the method being invoked, composed of the 36 * binary class name followed by the method descriptor (aka argument 37 * types). Example: "com/foo/MyClass/InnerClass/printInt(I)V". 38 * @param isNative True if the method was a native method. 39 * @param caller The calling object. Null for static methods, "this" for instance methods. 40 */ 41 public void onInvoke(String signature, boolean isNative, Object caller); 42 } 43 44 /** Map of method overridden. */ 45 private static HashMap<String, MethodListener> sMethods = new HashMap<String, MethodListener>(); 46 /** Default listener for all method not listed in sMethods. Nothing if null. */ 47 private static MethodListener sDefaultListener = null; 48 49 /** 50 * Sets the default listener for all methods not specifically handled. 51 * Null means to do nothing. 52 */ 53 public static void setDefaultListener(MethodListener listener) { 54 sDefaultListener = listener; 55 } 56 57 /** 58 * Defines or reset a listener for the given method signature. 59 * 60 * @param signature The signature of the method being invoked, composed of the 61 * binary class name followed by the method descriptor (aka argument 62 * types). Example: "com/foo/MyClass/InnerClass/printInt(I)V" 63 * @param listener The new listener. Removes it if null. 64 */ 65 public static void setMethodListener(String signature, MethodListener listener) { 66 if (listener == null) { 67 sMethods.remove(signature); 68 } else { 69 sMethods.put(signature, listener); 70 } 71 } 72 73 /** 74 * Invoke the specific listener for the given signature or the default one if defined. 75 * <p/> 76 * Note: this is not intended to be used by the LayoutLib Bridge. It is intended to be called 77 * by the stubbed methods generated by the LayoutLib_create tool. 78 * 79 * @param signature The signature of the method being invoked, composed of the 80 * binary class name followed by the method descriptor (aka argument 81 * types). Example: "com/foo/MyClass/InnerClass/printInt(I)V". 82 * @param isNative True if the method was a native method. 83 * @param caller The calling object. Null for static methods, "this" for instance methods. 84 */ 85 public static void invoke(String signature, boolean isNative, Object caller) { 86 MethodListener i = sMethods.get(signature); 87 if (i != null) { 88 i.onInvoke(signature, isNative, caller); 89 } else if (sDefaultListener != null) { 90 sDefaultListener.onInvoke(signature, isNative, caller); 91 } 92 } 93} 94