1579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson/* 2579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Copyright (C) 2007 The Android Open Source Project 3579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * 4579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Licensed under the Apache License, Version 2.0 (the "License"); 5579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * you may not use this file except in compliance with the License. 6579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * You may obtain a copy of the License at 7579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * 8579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * http://www.apache.org/licenses/LICENSE-2.0 9579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * 10579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Unless required by applicable law or agreed to in writing, software 11579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * distributed under the License is distributed on an "AS IS" BASIS, 12579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * See the License for the specific language governing permissions and 14579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * limitations under the License. 15579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 16579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 17579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilsonpackage com.android.dx.util; 18579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 19579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson/** 20579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Very simple base class that implements a flag to control the mutability 21579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * of instances. This class just provides the flag and a utility to check 22579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * and throw the right exception, but it is up to subclasses to place calls 23579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * to the checker in all the right places. 24579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 25579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilsonpublic class MutabilityControl { 26579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** whether this instance is mutable */ 27579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson private boolean mutable; 28579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 29579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 30579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Constructs an instance. It is initially mutable. 31579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 32579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public MutabilityControl() { 33579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson mutable = true; 34579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 35579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 36579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 37579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Constructs an instance, explicitly indicating the mutability. 38579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * 39579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * @param mutable {@code true} iff this instance is mutable 40579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 41579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public MutabilityControl(boolean mutable) { 42579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson this.mutable = mutable; 43579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 44579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 45579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 46579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Makes this instance immutable. 47579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 48579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public void setImmutable() { 49579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson mutable = false; 50579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 51579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 52579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 53579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Checks to see whether or not this instance is immutable. This is the 54579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * same as calling {@code !isMutable()}. 55579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * 56579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * @return {@code true} iff this instance is immutable 57579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 58579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public final boolean isImmutable() { 59579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson return !mutable; 60579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 61579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 62579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 63579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Checks to see whether or not this instance is mutable. 64579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * 65579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * @return {@code true} iff this instance is mutable 66579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 67579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public final boolean isMutable() { 68579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson return mutable; 69579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 70579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 71579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 72579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Throws {@link MutabilityException} if this instance is 73579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * immutable. 74579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 75579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public final void throwIfImmutable() { 76579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson if (!mutable) { 77579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson throw new MutabilityException("immutable instance"); 78579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 79579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 80579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson 81579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson /** 82579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson * Throws {@link MutabilityException} if this instance is mutable. 83579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson */ 84579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson public final void throwIfMutable() { 85579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson if (mutable) { 86579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson throw new MutabilityException("mutable instance"); 87579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 88579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson } 89579d7739c53a2707ad711a2d2cae46d7d782f06Jesse Wilson} 90