| /* |
| * 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.datastore.impl; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| |
| import org.apache.carbondata.core.constants.CarbonCommonConstants; |
| import org.apache.carbondata.core.datastore.FileReader; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FSDataInputStream; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| |
| public class DFSFileReaderImpl implements FileReader { |
| /** |
| * cache to hold filename and its stream |
| */ |
| protected Map<String, FSDataInputStream> fileNameAndStreamCache; |
| |
| private boolean readPageByPage; |
| |
| private Configuration configuration; |
| |
| public DFSFileReaderImpl(Configuration configuration) { |
| this.configuration = configuration; |
| this.fileNameAndStreamCache = |
| new HashMap<String, FSDataInputStream>(CarbonCommonConstants.DEFAULT_COLLECTION_SIZE); |
| } |
| |
| @Override |
| public byte[] readByteArray(String filePath, long offset, int length) |
| throws IOException { |
| FSDataInputStream fileChannel = updateCache(filePath); |
| return read(fileChannel, length, offset); |
| } |
| |
| /** |
| * This method will be used to check whether stream is already present in |
| * cache or not for filepath if not present then create it and then add to |
| * cache, other wise get from cache |
| * |
| * @param filePath fully qualified file path |
| * @return channel |
| */ |
| public FSDataInputStream updateCache(String filePath) throws IOException { |
| FSDataInputStream fileChannel = fileNameAndStreamCache.get(filePath); |
| if (null == fileChannel) { |
| Path pt = new Path(filePath); |
| FileSystem fs = pt.getFileSystem(configuration); |
| fileChannel = fs.open(pt); |
| fileNameAndStreamCache.put(filePath, fileChannel); |
| } |
| return fileChannel; |
| } |
| |
| /** |
| * This method will be used to read from file based on number of bytes to be read and position |
| * |
| * @param channel file channel |
| * @param size number of bytes |
| * @param offset position |
| * @return byte buffer |
| */ |
| private byte[] read(FSDataInputStream channel, int size, long offset) throws IOException { |
| byte[] byteBuffer = new byte[size]; |
| channel.seek(offset); |
| channel.readFully(byteBuffer); |
| return byteBuffer; |
| } |
| |
| /** |
| * This method will be used to read from file based on number of bytes to be read and position |
| * |
| * @param channel file channel |
| * @param size number of bytes |
| * @return byte buffer |
| */ |
| private byte[] read(FSDataInputStream channel, int size) throws IOException { |
| byte[] byteBuffer = new byte[size]; |
| channel.readFully(byteBuffer); |
| return byteBuffer; |
| } |
| |
| @Override |
| public int readInt(String filePath, long offset) throws IOException { |
| FSDataInputStream fileChannel = updateCache(filePath); |
| fileChannel.seek(offset); |
| return fileChannel.readInt(); |
| } |
| |
| @Override |
| public long readDouble(String filePath, long offset) throws IOException { |
| FSDataInputStream fileChannel = updateCache(filePath); |
| fileChannel.seek(offset); |
| return fileChannel.readLong(); |
| } |
| |
| @Override |
| public void finish() throws IOException { |
| for (Entry<String, FSDataInputStream> entry : fileNameAndStreamCache.entrySet()) { |
| FSDataInputStream channel = entry.getValue(); |
| if (null != channel) { |
| channel.close(); |
| } |
| } |
| } |
| |
| @Override |
| public byte[] readByteArray(String filePath, int length) throws IOException { |
| FSDataInputStream fileChannel = updateCache(filePath); |
| return read(fileChannel, length); |
| } |
| |
| @Override |
| public long readLong(String filePath, long offset) throws IOException { |
| FSDataInputStream fileChannel = updateCache(filePath); |
| fileChannel.seek(offset); |
| return fileChannel.readLong(); |
| } |
| |
| @Override |
| public int readInt(String filePath) throws IOException { |
| FSDataInputStream fileChannel = updateCache(filePath); |
| return fileChannel.readInt(); |
| } |
| |
| @Override |
| public ByteBuffer readByteBuffer(String filePath, long offset, int length) |
| throws IOException { |
| byte[] readByteArray = readByteArray(filePath, offset, length); |
| ByteBuffer byteBuffer = ByteBuffer.wrap(readByteArray); |
| byteBuffer.rewind(); |
| return byteBuffer; |
| } |
| |
| @Override |
| public void setReadPageByPage(boolean isReadPageByPage) { |
| this.readPageByPage = isReadPageByPage; |
| } |
| |
| @Override |
| public boolean isReadPageByPage() { |
| return readPageByPage; |
| } |
| |
| public Map<String, FSDataInputStream> getFileNameAndStreamCache() { |
| return fileNameAndStreamCache; |
| } |
| |
| } |