Java tutorial
/* * Copyright 2014 sonaive.com. All rights reserved. * * 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.sonaive.v2ex.io; import android.content.ContentProviderOperation; import android.content.Context; import android.database.Cursor; import android.net.Uri; import android.os.Bundle; import android.provider.BaseColumns; import android.text.TextUtils; import com.google.gson.Gson; import com.google.gson.JsonElement; import com.sonaive.v2ex.io.model.Node; import com.sonaive.v2ex.provider.V2exContract; import com.sonaive.v2ex.sync.api.Api; import java.util.ArrayList; import java.util.HashMap; import java.util.HashSet; import static com.sonaive.v2ex.util.LogUtils.LOGD; import static com.sonaive.v2ex.util.LogUtils.LOGE; import static com.sonaive.v2ex.util.LogUtils.LOGW; import static com.sonaive.v2ex.util.LogUtils.makeLogTag; /** * Created by liutao on 12/15/14. */ public class NodesHandler extends JSONHandler { private static final String TAG = makeLogTag(NodesHandler.class); // The api type. private int apiType; private HashMap<String, Node> mNodes = new HashMap<>(); public NodesHandler(Context context) { super(context); } @Override public void makeContentProviderOperations(ArrayList<ContentProviderOperation> list) { Uri uri = V2exContract.Nodes.CONTENT_URI; HashMap<String, String> nodeHashcodes = loadNodeHashcodes(); HashSet<String> nodesToKeep = new HashSet<>(); boolean isIncrementalUpdate = nodeHashcodes != null && nodeHashcodes.size() > 0; if (isIncrementalUpdate) { LOGD(TAG, "Doing incremental update for nodes."); } else { LOGD(TAG, "Doing FULL (non incremental) update for nodes."); list.add(ContentProviderOperation.newDelete(uri).build()); } int updatedNodes = 0; for (Node node : mNodes.values()) { String hashCode = node.getImportHashcode(); nodesToKeep.add(String.valueOf(node.id)); // add node, if necessary if (!isIncrementalUpdate || !nodeHashcodes.containsKey(String.valueOf(node.id)) || !nodeHashcodes.get(String.valueOf(node.id)).equals(hashCode)) { ++updatedNodes; boolean isNew = !isIncrementalUpdate || !nodeHashcodes.containsKey(String.valueOf(node.id)); buildNode(isNew, node, list); } } LOGD(TAG, "Nodes: " + (isIncrementalUpdate ? "INCREMENTAL" : "FULL") + " update. " + updatedNodes + " to update, New total: " + mNodes.size()); } @Override public void process(JsonElement element) { if (element.isJsonArray()) { for (Node node : new Gson().fromJson(element, Node[].class)) { mNodes.put(String.valueOf(node.id), node); } } else { Node node = new Gson().fromJson(element, Node.class); mNodes.put(String.valueOf(node.id), node); } } @Override public String getBody(Bundle data) { if (data != null) { apiType = data.getInt(Api.ARG_TYPE); return data.getString(Api.ARG_RESULT); } return ""; } private void buildNode(boolean isInsert, Node node, ArrayList<ContentProviderOperation> list) { Uri allVideosUri = V2exContract.addCallerIsSyncAdapterParameter(V2exContract.Nodes.CONTENT_URI); Uri thisVideoUri = V2exContract .addCallerIsSyncAdapterParameter(V2exContract.Nodes.buildNodeUri(String.valueOf(node.id))); ContentProviderOperation.Builder builder; if (isInsert) { builder = ContentProviderOperation.newInsert(allVideosUri); } else { builder = ContentProviderOperation.newUpdate(thisVideoUri); } if (TextUtils.isEmpty(String.valueOf(node.id))) { LOGW(TAG, "Ignoring feed with missing feed ID."); return; } list.add(builder.withValue(V2exContract.Nodes.NODE_ID, node.id) .withValue(V2exContract.Nodes.NODE_NAME, node.name).withValue(V2exContract.Nodes.NODE_URL, node.url) .withValue(V2exContract.Nodes.NODE_TITLE, node.title) .withValue(V2exContract.Nodes.NODE_TITLE_ALTERNATIVE, node.title_alternative) .withValue(V2exContract.Nodes.NODE_TOPICS, node.topics) .withValue(V2exContract.Nodes.NODE_HEADER, node.header) .withValue(V2exContract.Nodes.NODE_FOOTER, node.footer) .withValue(V2exContract.Nodes.NODE_CREATED, node.created) .withValue(V2exContract.Nodes.NODE_AVATAR_MINI, node.avatar_mini) .withValue(V2exContract.Nodes.NODE_AVATAR_NORMAL, node.avatar_normal) .withValue(V2exContract.Nodes.NODE_AVATAR_LARGE, node.avatar_large) .withValue(V2exContract.Nodes.NODE_IMPORT_HASHCODE, node.getImportHashcode()).build()); } private void buildDeleteOperation(String nodeId, ArrayList<ContentProviderOperation> list) { Uri uri = V2exContract.addCallerIsSyncAdapterParameter(V2exContract.Nodes.buildNodeUri(nodeId)); list.add(ContentProviderOperation.newDelete(uri).build()); } private HashMap<String, String> loadNodeHashcodes() { Uri uri = V2exContract.Nodes.CONTENT_URI; Cursor cursor = mContext.getContentResolver().query(uri, NodeHashcodeQuery.PROJECTION, null, null, null); if (cursor == null) { LOGE(TAG, "Error querying node hashcodes (got null cursor)"); return null; } if (cursor.getCount() < 1) { LOGE(TAG, "Error querying node hashcodes (no records returned)"); cursor.close(); return null; } HashMap<String, String> result = new HashMap<>(); while (cursor.moveToNext()) { String feedId = cursor.getString(NodeHashcodeQuery.NODE_ID); String hashcode = cursor.getString(NodeHashcodeQuery.NODE_IMPORT_HASHCODE); result.put(feedId, hashcode == null ? "" : hashcode); } cursor.close(); return result; } private interface NodeHashcodeQuery { String[] PROJECTION = { BaseColumns._ID, V2exContract.Nodes.NODE_ID, V2exContract.Nodes.NODE_IMPORT_HASHCODE }; final int _ID = 0; final int NODE_ID = 1; final int NODE_IMPORT_HASHCODE = 2; } }