113 lines
3.3 KiB
Java
113 lines
3.3 KiB
Java
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.database.sqlite;
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import android.compat.annotation.UnsupportedAppUsage;
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import java.io.Closeable;
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/**
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* An object created from a SQLiteDatabase that can be closed.
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*
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* This class implements a primitive reference counting scheme for database objects.
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*/
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@android.ravenwood.annotation.RavenwoodKeepWholeClass
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public abstract class SQLiteClosable implements Closeable {
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@UnsupportedAppUsage
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private int mReferenceCount = 1;
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/**
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* Called when the last reference to the object was released by
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* a call to {@link #releaseReference()} or {@link #close()}.
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*/
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protected abstract void onAllReferencesReleased();
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/**
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* Called when the last reference to the object was released by
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* a call to {@link #releaseReferenceFromContainer()}.
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*
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* @deprecated Do not use.
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*/
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@Deprecated
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protected void onAllReferencesReleasedFromContainer() {
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onAllReferencesReleased();
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}
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/**
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* Acquires a reference to the object.
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*
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* @throws IllegalStateException if the last reference to the object has already
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* been released.
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*/
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public void acquireReference() {
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synchronized(this) {
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if (mReferenceCount <= 0) {
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throw new IllegalStateException(
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"attempt to re-open an already-closed object: " + this);
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}
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mReferenceCount++;
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}
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}
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/**
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* Releases a reference to the object, closing the object if the last reference
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* was released.
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*
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* @see #onAllReferencesReleased()
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*/
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public void releaseReference() {
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boolean refCountIsZero = false;
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synchronized(this) {
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refCountIsZero = --mReferenceCount == 0;
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}
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if (refCountIsZero) {
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onAllReferencesReleased();
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}
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}
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/**
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* Releases a reference to the object that was owned by the container of the object,
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* closing the object if the last reference was released.
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*
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* @see #onAllReferencesReleasedFromContainer()
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* @deprecated Do not use.
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*/
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@Deprecated
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public void releaseReferenceFromContainer() {
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boolean refCountIsZero = false;
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synchronized(this) {
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refCountIsZero = --mReferenceCount == 0;
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}
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if (refCountIsZero) {
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onAllReferencesReleasedFromContainer();
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}
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}
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/**
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* Releases a reference to the object, closing the object if the last reference
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* was released.
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*
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* Calling this method is equivalent to calling {@link #releaseReference}.
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*
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* @see #releaseReference()
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* @see #onAllReferencesReleased()
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*/
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public void close() {
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releaseReference();
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}
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}
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