| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.carbondata.core.reader; |
| |
| import java.io.BufferedReader; |
| import java.io.DataInputStream; |
| import java.io.IOException; |
| import java.io.InputStreamReader; |
| import java.io.StringWriter; |
| |
| import org.apache.carbondata.core.constants.CarbonCommonConstants; |
| import org.apache.carbondata.core.datastore.impl.FileFactory; |
| import org.apache.carbondata.core.fileoperations.AtomicFileOperationFactory; |
| import org.apache.carbondata.core.fileoperations.AtomicFileOperations; |
| import org.apache.carbondata.core.mutate.DeleteDeltaBlockDetails; |
| import org.apache.carbondata.core.util.CarbonUtil; |
| |
| import com.google.gson.Gson; |
| |
| /** |
| * This class perform the functionality of reading the delete delta file |
| */ |
| public class CarbonDeleteDeltaFileReaderImpl implements CarbonDeleteDeltaFileReader { |
| |
| private String filePath; |
| |
| private static final int DEFAULT_BUFFER_SIZE = 258; |
| |
| /** |
| * @param filePath |
| */ |
| public CarbonDeleteDeltaFileReaderImpl(String filePath) { |
| this.filePath = filePath; |
| } |
| |
| /** |
| * This method will be used to read complete delete delta file. |
| * scenario: |
| * Whenever a query is executed then read the delete delta file |
| * to exclude the deleted data. |
| * |
| * @return All deleted records for the specified block |
| * @throws IOException if an I/O error occurs |
| */ |
| @Override |
| public String read() throws IOException { |
| // Configure Buffer based on our requirement |
| char[] buffer = new char[DEFAULT_BUFFER_SIZE]; |
| StringWriter sw = new StringWriter(); |
| try (DataInputStream dataInputStream = FileFactory.getDataInputStream(filePath); |
| InputStreamReader inputStream = new InputStreamReader(dataInputStream, |
| CarbonCommonConstants.DEFAULT_CHARSET)) { |
| int n = 0; |
| while (-1 != (n = inputStream.read(buffer))) { |
| sw.write(buffer, 0, n); |
| } |
| return sw.toString(); |
| } |
| } |
| |
| /** |
| * Reads delete delta file (json file) and returns DeleteDeltaBlockDetails |
| * @return DeleteDeltaBlockDetails |
| */ |
| @Override |
| public DeleteDeltaBlockDetails readJson() { |
| Gson gsonObjectToRead = new Gson(); |
| DataInputStream dataInputStream = null; |
| BufferedReader buffReader = null; |
| InputStreamReader inStream = null; |
| DeleteDeltaBlockDetails deleteDeltaBlockDetails; |
| AtomicFileOperations fileOperation = |
| AtomicFileOperationFactory.getAtomicFileOperations(filePath); |
| try { |
| if (!FileFactory.isFileExist(filePath)) { |
| return new DeleteDeltaBlockDetails(""); |
| } |
| dataInputStream = fileOperation.openForRead(); |
| inStream = new InputStreamReader(dataInputStream, |
| CarbonCommonConstants.DEFAULT_CHARSET); |
| buffReader = new BufferedReader(inStream); |
| deleteDeltaBlockDetails = |
| gsonObjectToRead.fromJson(buffReader, DeleteDeltaBlockDetails.class); |
| } catch (IOException e) { |
| return new DeleteDeltaBlockDetails(""); |
| } finally { |
| CarbonUtil.closeStreams(buffReader, inStream, dataInputStream); |
| } |
| |
| return deleteDeltaBlockDetails; |
| } |
| } |