| /* |
| * 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.FileInputStream; |
| import java.io.FileNotFoundException; |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.nio.channels.FileChannel; |
| 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; |
| |
| public class FileReaderImpl implements FileReader { |
| /** |
| * cache to hold filename and its stream |
| */ |
| private Map<String, FileChannel> fileNameAndStreamCache; |
| |
| private boolean readPageByPage; |
| |
| /** |
| * FileReaderImpl Constructor |
| * It will create the cache |
| */ |
| public FileReaderImpl() { |
| this.fileNameAndStreamCache = |
| new HashMap<String, FileChannel>(CarbonCommonConstants.DEFAULT_COLLECTION_SIZE); |
| } |
| |
| public FileReaderImpl(int capacity) { |
| this.fileNameAndStreamCache = new HashMap<String, FileChannel>(capacity); |
| } |
| |
| /** |
| * This method will be used to read the byte array from file based on offset |
| * and length(number of bytes) need to read |
| * |
| * @param filePath fully qualified file path |
| * @param offset reading start position, |
| * @param length number of bytes to be read |
| * @return read byte array |
| */ |
| @Override |
| public byte[] readByteArray(String filePath, long offset, int length) |
| throws IOException { |
| FileChannel fileChannel = updateCache(filePath); |
| ByteBuffer byteBuffer = read(fileChannel, length, offset); |
| return byteBuffer.array(); |
| } |
| |
| /** |
| * This method will be used to close all the streams currently present in the cache |
| */ |
| @Override |
| public void finish() throws IOException { |
| for (Entry<String, FileChannel> entry : fileNameAndStreamCache.entrySet()) { |
| FileChannel channel = entry.getValue(); |
| if (null != channel) { |
| channel.close(); |
| } |
| } |
| fileNameAndStreamCache.clear(); |
| } |
| |
| /** |
| * This method will be used to read int from file from position(offset), here |
| * length will be always 4 because int byte size if 4 |
| * |
| * @param filePath fully qualified file path |
| * @param offset reading start position, |
| * @return read int |
| */ |
| @Override |
| public int readInt(String filePath, long offset) throws IOException { |
| FileChannel fileChannel = updateCache(filePath); |
| ByteBuffer byteBuffer = read(fileChannel, CarbonCommonConstants.INT_SIZE_IN_BYTE, offset); |
| return byteBuffer.getInt(); |
| } |
| |
| /** |
| * This method will be used to read int from file from position(offset), here |
| * length will be always 4 because int byte size if 4 |
| * |
| * @param filePath fully qualified file path |
| * @return read int |
| */ |
| @Override |
| public int readInt(String filePath) throws IOException { |
| FileChannel fileChannel = updateCache(filePath); |
| ByteBuffer byteBuffer = read(fileChannel, CarbonCommonConstants.INT_SIZE_IN_BYTE); |
| return byteBuffer.getInt(); |
| } |
| |
| /** |
| * This method will be used to read int from file from position(offset), here |
| * length will be always 4 because int byte size if 4 |
| * |
| * @param filePath fully qualified file path |
| * @param offset reading start position, |
| * @return read int |
| */ |
| @Override |
| public long readDouble(String filePath, long offset) throws IOException { |
| FileChannel fileChannel = updateCache(filePath); |
| ByteBuffer byteBuffer = read(fileChannel, CarbonCommonConstants.LONG_SIZE_IN_BYTE, offset); |
| return byteBuffer.getLong(); |
| } |
| |
| /** |
| * 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 |
| */ |
| private FileChannel updateCache(String filePath) throws FileNotFoundException { |
| FileChannel fileChannel = fileNameAndStreamCache.get(filePath); |
| if (null == fileChannel) { |
| FileInputStream stream = new FileInputStream(filePath); |
| fileChannel = stream.getChannel(); |
| 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 ByteBuffer read(FileChannel channel, int size, long offset) throws IOException { |
| ByteBuffer byteBuffer = ByteBuffer.allocate(size); |
| channel.position(offset); |
| channel.read(byteBuffer); |
| byteBuffer.rewind(); |
| 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 ByteBuffer read(FileChannel channel, int size) throws IOException { |
| ByteBuffer byteBuffer = ByteBuffer.allocate(size); |
| channel.read(byteBuffer); |
| byteBuffer.rewind(); |
| return byteBuffer; |
| } |
| |
| |
| /** |
| * This method will be used to read the byte array from file based on length(number of bytes) |
| * |
| * @param filePath fully qualified file path |
| * @param length number of bytes to be read |
| * @return read byte array |
| */ |
| @Override |
| public byte[] readByteArray(String filePath, int length) throws IOException { |
| FileChannel fileChannel = updateCache(filePath); |
| ByteBuffer byteBuffer = read(fileChannel, length); |
| return byteBuffer.array(); |
| } |
| |
| /** |
| * This method will be used to read long from file from position(offset), here |
| * length will be always 8 because int byte size is 8 |
| * |
| * @param filePath fully qualified file path |
| * @param offset reading start position, |
| * @return read long |
| */ |
| @Override |
| public long readLong(String filePath, long offset) throws IOException { |
| FileChannel fileChannel = updateCache(filePath); |
| ByteBuffer byteBuffer = read(fileChannel, CarbonCommonConstants.LONG_SIZE_IN_BYTE, offset); |
| return byteBuffer.getLong(); |
| } |
| |
| @Override |
| public ByteBuffer readByteBuffer(String filePath, long offset, int length) |
| throws IOException { |
| ByteBuffer byteBuffer = ByteBuffer.allocate(length); |
| FileChannel fileChannel = updateCache(filePath); |
| fileChannel.position(offset); |
| fileChannel.read(byteBuffer); |
| byteBuffer.rewind(); |
| return byteBuffer; |
| } |
| |
| @Override |
| public void setReadPageByPage(boolean isReadPageByPage) { |
| this.readPageByPage = isReadPageByPage; |
| } |
| |
| @Override |
| public boolean isReadPageByPage() { |
| return readPageByPage; |
| } |
| } |