1917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul/* 2917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Copyright (C) 2007 The Android Open Source Project 3917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * 4917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Licensed under the Apache License, Version 2.0 (the "License"); 5917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * you may not use this file except in compliance with the License. 6917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * You may obtain a copy of the License at 7917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * 8917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * http://www.apache.org/licenses/LICENSE-2.0 9917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * 10917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Unless required by applicable law or agreed to in writing, software 11917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * distributed under the License is distributed on an "AS IS" BASIS, 12917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * See the License for the specific language governing permissions and 14917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * limitations under the License. 15917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 16917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 17917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgulpackage com.android.dexgen.util; 18917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 19917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul/** 20917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Very simple base class that implements a flag to control the mutability 21917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * of instances. This class just provides the flag and a utility to check 22917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * and throw the right exception, but it is up to subclasses to place calls 23917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * to the checker in all the right places. 24917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 25917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgulpublic class MutabilityControl { 26917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** whether this instance is mutable */ 27917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul private boolean mutable; 28917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 29917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 30917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Constructs an instance. It is initially mutable. 31917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 32917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public MutabilityControl() { 33917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul mutable = true; 34917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 35917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 36917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 37917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Constructs an instance, explicitly indicating the mutability. 38917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * 39917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * @param mutable {@code true} iff this instance is mutable 40917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 41917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public MutabilityControl(boolean mutable) { 42917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul this.mutable = mutable; 43917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 44917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 45917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 46917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Makes this instance immutable. 47917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 48917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public void setImmutable() { 49917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul mutable = false; 50917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 51917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 52917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 53917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Checks to see whether or not this instance is immutable. This is the 54917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * same as calling {@code !isMutable()}. 55917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * 56917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * @return {@code true} iff this instance is immutable 57917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 58917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public final boolean isImmutable() { 59917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul return !mutable; 60917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 61917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 62917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 63917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Checks to see whether or not this instance is mutable. 64917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * 65917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * @return {@code true} iff this instance is mutable 66917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 67917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public final boolean isMutable() { 68917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul return mutable; 69917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 70917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 71917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 72917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Throws {@link MutabilityException} if this instance is 73917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * immutable. 74917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 75917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public final void throwIfImmutable() { 76917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul if (!mutable) { 77917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul throw new MutabilityException("immutable instance"); 78917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 79917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 80917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul 81917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul /** 82917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul * Throws {@link MutabilityException} if this instance is mutable. 83917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul */ 84917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul public final void throwIfMutable() { 85917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul if (mutable) { 86917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul throw new MutabilityException("mutable instance"); 87917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 88917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul } 89917cb222329ee8c035c3ffaf947e4265761b9367Piotr Gurgul} 90