Java tutorial
/* * Licensed to Metamarkets Group Inc. (Metamarkets) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. Metamarkets 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 io.druid.segment.data; import com.google.common.io.ByteSink; import com.google.common.io.ByteStreams; import com.google.common.io.CountingOutputStream; import com.google.common.primitives.Ints; import io.druid.collections.ResourceHolder; import io.druid.collections.StupidResourceHolder; import io.druid.segment.CompressedPools; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.channels.Channels; import java.nio.channels.ReadableByteChannel; import java.nio.channels.WritableByteChannel; public class BlockLayoutLongSupplierSerializer implements LongSupplierSerializer { private final IOPeon ioPeon; private final int sizePer; private final CompressionFactory.LongEncodingWriter writer; private final GenericIndexedWriter<ResourceHolder<ByteBuffer>> flattener; private final CompressedObjectStrategy.CompressionStrategy compression; private final String metaFile; private long metaCount = 0; private int numInserted = 0; private ByteBuffer endBuffer = null; public BlockLayoutLongSupplierSerializer(IOPeon ioPeon, String filenameBase, ByteOrder order, CompressionFactory.LongEncodingWriter writer, CompressedObjectStrategy.CompressionStrategy compression) { this.ioPeon = ioPeon; this.sizePer = writer.getBlockSize(CompressedPools.BUFFER_SIZE); this.flattener = new GenericIndexedWriter<ResourceHolder<ByteBuffer>>(ioPeon, filenameBase, VSizeCompressedObjectStrategy.getBufferForOrder(order, compression, writer.getNumBytes(sizePer))); this.metaFile = filenameBase + ".format"; this.writer = writer; this.compression = compression; } @Override public void open() throws IOException { flattener.open(); } @Override public int size() { return numInserted; } @Override public void add(long value) throws IOException { if (numInserted % sizePer == 0) { if (endBuffer != null) { writer.flush(); endBuffer.limit(endBuffer.position()); endBuffer.rewind(); flattener.write(StupidResourceHolder.create(endBuffer)); } endBuffer = ByteBuffer.allocate(writer.getNumBytes(sizePer)); writer.setBuffer(endBuffer); } writer.write(value); ++numInserted; } @Override public void closeAndConsolidate(ByteSink consolidatedOut) throws IOException { close(); try (OutputStream out = consolidatedOut.openStream(); InputStream meta = ioPeon.makeInputStream(metaFile)) { ByteStreams.copy(meta, out); ByteStreams.copy(flattener.combineStreams(), out); } } @Override public void close() throws IOException { if (endBuffer != null) { writer.flush(); endBuffer.limit(endBuffer.position()); endBuffer.rewind(); flattener.write(StupidResourceHolder.create(endBuffer)); } endBuffer = null; flattener.close(); try (CountingOutputStream metaOut = new CountingOutputStream(ioPeon.makeOutputStream(metaFile))) { metaOut.write(CompressedLongsIndexedSupplier.version); metaOut.write(Ints.toByteArray(numInserted)); metaOut.write(Ints.toByteArray(sizePer)); writer.putMeta(metaOut, compression); metaOut.close(); metaCount = metaOut.getCount(); } } @Override public long getSerializedSize() { return metaCount + flattener.getSerializedSize(); } @Override public void writeToChannel(WritableByteChannel channel) throws IOException { try (InputStream meta = ioPeon.makeInputStream(metaFile); InputStream input = flattener.combineStreams().getInput()) { ByteStreams.copy(Channels.newChannel(meta), channel); final ReadableByteChannel from = Channels.newChannel(input); ByteStreams.copy(from, channel); } } }