1/* 2 * Copyright (C) 2007 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 android.database.sqlite; 18 19import android.database.CursorWindow; 20 21/** 22 * An object created from a SQLiteDatabase that can be closed. 23 */ 24public abstract class SQLiteClosable { 25 private int mReferenceCount = 1; 26 27 protected abstract void onAllReferencesReleased(); 28 protected void onAllReferencesReleasedFromContainer() {} 29 30 public void acquireReference() { 31 synchronized(this) { 32 if (mReferenceCount <= 0) { 33 throw new IllegalStateException( 34 "attempt to re-open an already-closed object: " + getObjInfo()); 35 } 36 mReferenceCount++; 37 } 38 } 39 40 public void releaseReference() { 41 boolean refCountIsZero = false; 42 synchronized(this) { 43 refCountIsZero = --mReferenceCount == 0; 44 } 45 if (refCountIsZero) { 46 onAllReferencesReleased(); 47 } 48 } 49 50 public void releaseReferenceFromContainer() { 51 boolean refCountIsZero = false; 52 synchronized(this) { 53 refCountIsZero = --mReferenceCount == 0; 54 } 55 if (refCountIsZero) { 56 onAllReferencesReleasedFromContainer(); 57 } 58 } 59 60 private String getObjInfo() { 61 StringBuilder buff = new StringBuilder(); 62 buff.append(this.getClass().getName()); 63 buff.append(" ("); 64 if (this instanceof SQLiteDatabase) { 65 buff.append("database = "); 66 buff.append(((SQLiteDatabase)this).getPath()); 67 } else if (this instanceof SQLiteProgram) { 68 buff.append("mSql = "); 69 buff.append(((SQLiteProgram)this).mSql); 70 } else if (this instanceof CursorWindow) { 71 buff.append("mStartPos = "); 72 buff.append(((CursorWindow)this).getStartPosition()); 73 } 74 buff.append(") "); 75 return buff.toString(); 76 } 77} 78