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 * <p/>
24 * Implementation note: all types required by this class(inner/outer classes & interfaces)
25 * must be referenced by the injectClass argument to {@link AsmGenerator} in Main.java;
26 * Otherwise they won't be accessible in layoutlib.jar at runtime.
27 */
28public final class OverrideMethod {
29
30    /** Map of method overridden. */
31    private static HashMap<String, MethodListener> sMethods = new HashMap<String, MethodListener>();
32    /** Default listener for all method not listed in sMethods. Nothing if null. */
33    private static MethodListener sDefaultListener = null;
34
35    /**
36     * Sets the default listener for all methods not specifically handled.
37     * Null means to do nothing.
38     */
39    public static void setDefaultListener(MethodListener listener) {
40        sDefaultListener = listener;
41    }
42
43    /**
44     * Defines or reset a listener for the given method signature.
45     *
46     * @param signature The signature of the method being invoked, composed of the
47     *                  binary class name followed by the method descriptor (aka argument
48     *                  types). Example: "com/foo/MyClass/InnerClass/printInt(I)V"
49     * @param listener The new listener. Removes it if null.
50     */
51    public static void setMethodListener(String signature, MethodListener listener) {
52        if (listener == null) {
53            sMethods.remove(signature);
54        } else {
55            sMethods.put(signature, listener);
56        }
57    }
58
59    /**
60     * Invokes the specific listener for the given signature or the default one if defined.
61     * <p/>
62     * This version invokes the method listener for the void return type.
63     * <p/>
64     * Note: this is not intended to be used by the LayoutLib Bridge. It is intended to be called
65     * by the stubbed methods generated by the LayoutLib_create tool.
66     *
67     * @param signature The signature of the method being invoked, composed of the
68     *                  binary class name followed by the method descriptor (aka argument
69     *                  types). Example: "com/foo/MyClass/InnerClass/printInt(I)V".
70     * @param isNative True if the method was a native method.
71     * @param caller The calling object. Null for static methods, "this" for instance methods.
72     */
73    public static void invokeV(String signature, boolean isNative, Object caller) {
74        MethodListener i = sMethods.get(signature);
75        if (i != null) {
76            i.onInvokeV(signature, isNative, caller);
77        } else if (sDefaultListener != null) {
78            sDefaultListener.onInvokeV(signature, isNative, caller);
79        }
80    }
81
82    /**
83     * Invokes the specific listener for the int return type.
84     * @see #invokeV(String, boolean, Object)
85     */
86    public static int invokeI(String signature, boolean isNative, Object caller) {
87        MethodListener i = sMethods.get(signature);
88        if (i != null) {
89            return i.onInvokeI(signature, isNative, caller);
90        } else if (sDefaultListener != null) {
91            return sDefaultListener.onInvokeI(signature, isNative, caller);
92        }
93        return 0;
94    }
95
96    /**
97     * Invokes the specific listener for the long return type.
98     * @see #invokeV(String, boolean, Object)
99     */
100    public static long invokeL(String signature, boolean isNative, Object caller) {
101        MethodListener i = sMethods.get(signature);
102        if (i != null) {
103            return i.onInvokeL(signature, isNative, caller);
104        } else if (sDefaultListener != null) {
105            return sDefaultListener.onInvokeL(signature, isNative, caller);
106        }
107        return 0;
108    }
109
110    /**
111     * Invokes the specific listener for the float return type.
112     * @see #invokeV(String, boolean, Object)
113     */
114    public static float invokeF(String signature, boolean isNative, Object caller) {
115        MethodListener i = sMethods.get(signature);
116        if (i != null) {
117            return i.onInvokeF(signature, isNative, caller);
118        } else if (sDefaultListener != null) {
119            return sDefaultListener.onInvokeF(signature, isNative, caller);
120        }
121        return 0;
122    }
123
124    /**
125     * Invokes the specific listener for the double return type.
126     * @see #invokeV(String, boolean, Object)
127     */
128    public static double invokeD(String signature, boolean isNative, Object caller) {
129        MethodListener i = sMethods.get(signature);
130        if (i != null) {
131            return i.onInvokeD(signature, isNative, caller);
132        } else if (sDefaultListener != null) {
133            return sDefaultListener.onInvokeD(signature, isNative, caller);
134        }
135        return 0;
136    }
137
138    /**
139     * Invokes the specific listener for the object return type.
140     * @see #invokeV(String, boolean, Object)
141     */
142    public static Object invokeA(String signature, boolean isNative, Object caller) {
143        MethodListener i = sMethods.get(signature);
144        if (i != null) {
145            return i.onInvokeA(signature, isNative, caller);
146        } else if (sDefaultListener != null) {
147            return sDefaultListener.onInvokeA(signature, isNative, caller);
148        }
149        return null;
150    }
151}
152