Java tutorial
/* * Licensed to Elasticsearch under one or more contributor * license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright * ownership. Elasticsearch 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.elasticsearch.hadoop.transport.netty4; import io.netty.buffer.ByteBuf; import io.netty.buffer.CompositeByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.util.internal.logging.InternalLogger; import io.netty.util.internal.logging.InternalLoggerFactory; import org.apache.lucene.util.BytesRef; import org.apache.lucene.util.BytesRefIterator; import org.elasticsearch.common.bytes.BytesReference; import java.io.IOException; import java.util.ArrayList; import java.util.Collection; import java.util.List; public class Netty4Utils { static { InternalLoggerFactory.setDefaultFactory(new InternalLoggerFactory() { @Override public InternalLogger newInstance(final String name) { return new Netty4InternalESLogger(name.replace("io.netty.", "netty.")); } }); } public static void setup() { } /** * Turns the given BytesReference into a ByteBuf. Note: the returned ByteBuf will reference the internal * pages of the BytesReference. Don't free the bytes of reference before the ByteBuf goes out of scope. */ public static ByteBuf toByteBuf(final BytesReference reference) { if (reference.length() == 0) { return Unpooled.EMPTY_BUFFER; } if (reference instanceof ByteBufBytesReference) { return ((ByteBufBytesReference) reference).toByteBuf(); } else { final BytesRefIterator iterator = reference.iterator(); // usually we have one, two, or three components // from the header, the message, and a buffer final List<ByteBuf> buffers = new ArrayList<>(3); try { BytesRef slice; while ((slice = iterator.next()) != null) { buffers.add(Unpooled.wrappedBuffer(slice.bytes, slice.offset, slice.length)); } final CompositeByteBuf composite = Unpooled.compositeBuffer(buffers.size()); composite.addComponents(true, buffers); return composite; } catch (IOException ex) { throw new AssertionError("no IO happens here", ex); } } } /** * Wraps the given ChannelBuffer with a BytesReference */ public static BytesReference toBytesReference(final ByteBuf buffer) { return toBytesReference(buffer, buffer.readableBytes()); } /** * Wraps the given ChannelBuffer with a BytesReference of a given size */ static BytesReference toBytesReference(final ByteBuf buffer, final int size) { return new ByteBufBytesReference(buffer, size); } public static void closeChannels(final Collection<Channel> channels) throws IOException { IOException closingExceptions = null; final List<ChannelFuture> futures = new ArrayList<>(); for (final Channel channel : channels) { try { if (channel != null && channel.isOpen()) { futures.add(channel.close()); } } catch (Exception e) { if (closingExceptions == null) { closingExceptions = new IOException("failed to close channels"); } closingExceptions.addSuppressed(e); } } for (final ChannelFuture future : futures) { future.awaitUninterruptibly(); } if (closingExceptions != null) { throw closingExceptions; } } }