/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License
*/
package com.android.common.content;
import android.content.ContentProvider;
import android.content.ContentProviderOperation;
import android.content.ContentProviderResult;
import android.content.ContentValues;
import android.content.Context;
import android.content.OperationApplicationException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteTransactionListener;
import android.net.Uri;
import java.util.ArrayList;
/**
* General purpose {@link ContentProvider} base class that uses SQLiteDatabase for storage.
*/
public abstract class SQLiteContentProvider extends ContentProvider
implements SQLiteTransactionListener {
private static final String TAG = "SQLiteContentProvider";
private SQLiteOpenHelper mOpenHelper;
private volatile boolean mNotifyChange;
protected SQLiteDatabase mDb;
private final ThreadLocal<Boolean> mApplyingBatch = new ThreadLocal<Boolean>();
private static final int SLEEP_AFTER_YIELD_DELAY = 4000;
/**
* Maximum number of operations allowed in a batch between yield points.
*/
private static final int MAX_OPERATIONS_PER_YIELD_POINT = 500;
/**
* @return Number of operations that can be applied at once without a yield point.
*/
public int getMaxOperationsPerYield() {
return MAX_OPERATIONS_PER_YIELD_POINT;
}
@Override
public boolean onCreate() {
Context context = getContext();
mOpenHelper = getDatabaseHelper(context);
return true;
}
protected abstract SQLiteOpenHelper getDatabaseHelper(Context context);
/**
* The equivalent of the {@link #insert} method, but invoked within a transaction.
*/
protected abstract Uri insertInTransaction(Uri uri, ContentValues values);
/**
* The equivalent of the {@link #update} method, but invoked within a transaction.
*/
protected abstract int updateInTransaction(Uri uri, ContentValues values, String selection,
String[] selectionArgs);
/**
* The equivalent of the {@link #delete} method, but invoked within a transaction.
*/
protected abstract int deleteInTransaction(Uri uri, String selection, String[] selectionArgs);
protected abstract void notifyChange();
public SQLiteOpenHelper getDatabaseHelper() {
return mOpenHelper;
}
private boolean applyingBatch() {
return mApplyingBatch.get() != null && mApplyingBatch.get();
}
@Override
public Uri insert(Uri uri, ContentValues values) {
Uri result = null;
boolean applyingBatch = applyingBatch();
if (!applyingBatch) {
mDb = mOpenHelper.getWritableDatabase();
mDb.beginTransactionWithListener(this);
try {
result = insertInTransaction(uri, values);
if (result != null) {
mNotifyChange = true;
}
mDb.setTransactionSuccessful();
} finally {
mDb.endTransaction();
}
onEndTransaction();
} else {
result = insertInTransaction(uri, values);
if (result != null) {
mNotifyChange = true;
}
}
return result;
}
@Override
public int bulkInsert(Uri uri, ContentValues[] values) {
int numValues = values.length;
mDb = mOpenHelper.getWritableDatabase();
mDb.beginTransactionWithListener(this);
try {
for (int i = 0; i < numValues; i++) {
Uri result = insertInTransaction(uri, values[i]);
if (result != null) {
mNotifyChange = true;
}
boolean savedNotifyChange = mNotifyChange;
SQLiteDatabase savedDb = mDb;
mDb.yieldIfContendedSafely();
mDb = savedDb;
mNotifyChange = savedNotifyChange;
}
mDb.setTransactionSuccessful();
} finally {
mDb.endTransaction();
}
onEndTransaction();
return numValues;
}
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
int count = 0;
boolean applyingBatch = applyingBatch();
if (!applyingBatch) {
mDb = mOpenHelper.getWritableDatabase();
mDb.beginTransactionWithListener(this);
try {
count = updateInTransaction(uri, values, selection, selectionArgs);
if (count > 0) {
mNotifyChange = true;
}
mDb.setTransactionSuccessful();
} finally {
mDb.endTransaction();
}
onEndTransaction();
} else {
count = updateInTransaction(uri, values, selection, selectionArgs);
if (count > 0) {
mNotifyChange = true;
}
}
return count;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int count = 0;
boolean applyingBatch = applyingBatch();
if (!applyingBatch) {
mDb = mOpenHelper.getWritableDatabase();
mDb.beginTransactionWithListener(this);
try {
count = deleteInTransaction(uri, selection, selectionArgs);
if (count > 0) {
mNotifyChange = true;
}
mDb.setTransactionSuccessful();
} finally {
mDb.endTransaction();
}
onEndTransaction();
} else {
count = deleteInTransaction(uri, selection, selectionArgs);
if (count > 0) {
mNotifyChange = true;
}
}
return count;
}
@Override
public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations)
throws OperationApplicationException {
int ypCount = 0;
int opCount = 0;
mDb = mOpenHelper.getWritableDatabase();
mDb.beginTransactionWithListener(this);
try {
mApplyingBatch.set(true);
final int numOperations = operations.size();
final ContentProviderResult[] results = new ContentProviderResult[numOperations];
for (int i = 0; i < numOperations; i++) {
if (++opCount > getMaxOperationsPerYield()) {
throw new OperationApplicationException(
"Too many content provider operations between yield points. "
+ "The maximum number of operations per yield point is "
+ MAX_OPERATIONS_PER_YIELD_POINT, ypCount);
}
final ContentProviderOperation operation = operations.get(i);
if (i > 0 && operation.isYieldAllowed()) {
opCount = 0;
boolean savedNotifyChange = mNotifyChange;
if (mDb.yieldIfContendedSafely(SLEEP_AFTER_YIELD_DELAY)) {
mDb = mOpenHelper.getWritableDatabase();
mNotifyChange = savedNotifyChange;
ypCount++;
}
}
results[i] = operation.apply(this, results, i);
}
mDb.setTransactionSuccessful();
return results;
} finally {
mApplyingBatch.set(false);
mDb.endTransaction();
onEndTransaction();
}
}
@Override
public void onBegin() {
onBeginTransaction();
}
@Override
public void onCommit() {
beforeTransactionCommit();
}
@Override
public void onRollback() {
// not used
}
protected void onBeginTransaction() {
}
protected void beforeTransactionCommit() {
}
protected void onEndTransaction() {
if (mNotifyChange) {
mNotifyChange = false;
notifyChange();
}
}
}
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