Android example source code file (WebViewWorker.java)

This example Android source code file (WebViewWorker.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, cache_transaction_ticker_interval, cachecreatedata, cachedata, cacheencoding, cachesavedata, frameloader, http, loadlistener, msg_add_streamloader, msg_cache_transaction_ticker, msg_remove_cache, msg_resume_cache_transaction, msg_update_cache_encoding, net, network, os, string, util, webviewworker

The WebViewWorker.java Android example source code

/*
 * Copyright (C) 2010 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 android.webkit;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import android.net.http.Headers;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Message;

/**
 * WebViewWorker executes in a separate thread other than UI and WebViewCore. To
 * avoid blocking UI or WebKit's execution, the caller can send a message to
 * WebViewWorker.getHandler() and it will be handled in the WebViewWorkerThread.
 */
final class WebViewWorker extends Handler {

    private static final String THREAD_NAME = "WebViewWorkerThread";

    private static WebViewWorker sWorkerHandler;

    private static Map<LoadListener, CacheManager.CacheResult> mCacheResultMap
            = new HashMap<LoadListener, CacheManager.CacheResult>();

    /**
     * Package level class to be used while creating a cache entry.
     */
    static class CacheCreateData {
        LoadListener mListener;
        String mUrl;
        String mMimeType;
        int mStatusCode;
        long mPostId;
        Headers mHeaders;
    }

    /**
     * Package level class to be used while saving a cache entry.
     */
    static class CacheSaveData {
        LoadListener mListener;
        String mUrl;
        long mPostId;
    }

    /**
     * Package level class to be used while updating a cache entry's encoding.
     */
    static class CacheEncoding {
        LoadListener mListener;
        String mEncoding;
    }

    /**
     * Package level class to be used while appending data to a cache entry.
     */
    static class CacheData {
        LoadListener mListener;
        ByteArrayBuilder.Chunk mChunk;
    }

    static synchronized WebViewWorker getHandler() {
        if (sWorkerHandler == null) {
            HandlerThread thread = new HandlerThread(THREAD_NAME,
                    android.os.Process.THREAD_PRIORITY_DEFAULT
                            + android.os.Process.THREAD_PRIORITY_LESS_FAVORABLE);
            thread.start();
            sWorkerHandler = new WebViewWorker(thread.getLooper());
        }
        return sWorkerHandler;
    }

    private WebViewWorker(Looper looper) {
        super(looper);
    }

    // trigger transaction once a minute
    private static final int CACHE_TRANSACTION_TICKER_INTERVAL = 60 * 1000;

    private static boolean mCacheTickersBlocked = true;

    // message ids
    static final int MSG_ADD_STREAMLOADER = 101;
    static final int MSG_ADD_HTTPLOADER = 102;
    static final int MSG_CREATE_CACHE = 103;
    static final int MSG_UPDATE_CACHE_ENCODING = 104;
    static final int MSG_APPEND_CACHE = 105;
    static final int MSG_SAVE_CACHE = 106;
    static final int MSG_REMOVE_CACHE = 107;
    static final int MSG_TRIM_CACHE = 108;
    static final int MSG_CLEAR_CACHE = 109;
    static final int MSG_CACHE_TRANSACTION_TICKER = 110;
    static final int MSG_PAUSE_CACHE_TRANSACTION = 111;
    static final int MSG_RESUME_CACHE_TRANSACTION = 112;

    @Override
    public void handleMessage(Message msg) {
        switch(msg.what) {
            case MSG_ADD_STREAMLOADER: {
                StreamLoader loader = (StreamLoader) msg.obj;
                loader.load();
                break;
            }
            case MSG_ADD_HTTPLOADER: {
                FrameLoader loader = (FrameLoader) msg.obj;
                loader.handleHTTPLoad();
                break;
            }
            case MSG_CREATE_CACHE: {
                CacheCreateData data = (CacheCreateData) msg.obj;
                CacheManager.CacheResult cache = CacheManager.createCacheFile(
                        data.mUrl, data.mStatusCode, data.mHeaders,
                        data.mMimeType, data.mPostId, false);
                if (cache != null) {
                    mCacheResultMap.put(data.mListener, cache);
                } else {
                    mCacheResultMap.remove(data.mListener);
                }
                break;
            }
            case MSG_UPDATE_CACHE_ENCODING: {
                CacheEncoding data = (CacheEncoding) msg.obj;
                CacheManager.CacheResult cache = mCacheResultMap
                        .get(data.mListener);
                if (cache != null) {
                    cache.encoding = data.mEncoding;
                }
                break;
            }
            case MSG_APPEND_CACHE: {
                CacheData data = (CacheData) msg.obj;
                CacheManager.CacheResult cache = mCacheResultMap
                        .get(data.mListener);
                if (cache != null) {
                    cache.contentLength += data.mChunk.mLength;
                    if (cache.contentLength > CacheManager.CACHE_MAX_SIZE) {
                        CacheManager.cleanupCacheFile(cache);
                        mCacheResultMap.remove(data.mListener);
                    } else {
                        try {
                            cache.outStream.write(data.mChunk.mArray, 0,
                                    data.mChunk.mLength);
                        } catch (IOException e) {
                            CacheManager.cleanupCacheFile(cache);
                            mCacheResultMap.remove(data.mListener);
                        }
                    }
                }
                data.mChunk.release();
                break;
            }
            case MSG_SAVE_CACHE: {
                CacheSaveData data = (CacheSaveData) msg.obj;
                CacheManager.CacheResult cache = mCacheResultMap
                        .get(data.mListener);
                if (cache != null) {
                    CacheManager.saveCacheFile(data.mUrl, data.mPostId, cache);
                    mCacheResultMap.remove(data.mListener);
                }
                break;
            }
            case MSG_REMOVE_CACHE: {
                LoadListener listener = (LoadListener) msg.obj;
                CacheManager.CacheResult cache = mCacheResultMap.get(listener);
                if (cache != null) {
                    CacheManager.cleanupCacheFile(cache);
                    mCacheResultMap.remove(listener);
                }
                break;
            }
            case MSG_TRIM_CACHE: {
                CacheManager.trimCacheIfNeeded();
                break;
            }
            case MSG_CLEAR_CACHE: {
                CacheManager.clearCache();
                break;
            }
            case MSG_CACHE_TRANSACTION_TICKER: {
                if (!mCacheTickersBlocked) {
                    CacheManager.endTransaction();
                    CacheManager.startTransaction();
                    sendEmptyMessageDelayed(MSG_CACHE_TRANSACTION_TICKER,
                            CACHE_TRANSACTION_TICKER_INTERVAL);
                }
                break;
            }
            case MSG_PAUSE_CACHE_TRANSACTION: {
                if (CacheManager.disableTransaction()) {
                    mCacheTickersBlocked = true;
                    removeMessages(MSG_CACHE_TRANSACTION_TICKER);
                }
                break;
            }
            case MSG_RESUME_CACHE_TRANSACTION: {
                if (CacheManager.enableTransaction()) {
                    mCacheTickersBlocked = false;
                    sendEmptyMessageDelayed(MSG_CACHE_TRANSACTION_TICKER,
                            CACHE_TRANSACTION_TICKER_INTERVAL);
                }
                break;
            }
        }
    }
}