Java tutorial
/* 50AH-code ========= 50 Android Hacks (http://manning.com/sessa/) book source code Copyright (c) 2012 Manning Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /******************************************************************************* * Copyright (c) 2012 Manning * See the file license.txt for copying permission. ******************************************************************************/ package com.manning.androidhacks.hack043.provider; import java.util.ArrayList; 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; public abstract class SQLiteContentProvider extends ContentProvider implements SQLiteTransactionListener { 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; @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(); protected 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; } mDb.yieldIfContendedSafely(); } 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) { // HARDOCDED FALSE to avoid notifications! mNotifyChange = false; } } return count; } @Override public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations) throws OperationApplicationException { 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++) { final ContentProviderOperation operation = operations.get(i); if (i > 0 && operation.isYieldAllowed()) { mDb.yieldIfContendedSafely(SLEEP_AFTER_YIELD_DELAY); } results[i] = operation.apply(this, results, i); } mDb.setTransactionSuccessful(); return results; } finally { mApplyingBatch.set(false); mDb.endTransaction(); onEndTransaction(); } } public void onBegin() { onBeginTransaction(); } public void onCommit() { beforeTransactionCommit(); } public void onRollback() { // not used } protected void onBeginTransaction() { } protected void beforeTransactionCommit() { } protected void onEndTransaction() { if (mNotifyChange) { mNotifyChange = false; notifyChange(); } } }