Java tutorial
/* * 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.ignite.internal.processors.hadoop.impl.igfs; import org.apache.commons.logging.Log; import org.apache.ignite.IgniteCheckedException; import org.apache.ignite.internal.igfs.common.IgfsLogger; import org.jetbrains.annotations.NotNull; import java.io.IOException; import java.io.OutputStream; /** * IGFS Hadoop output stream implementation. */ public class HadoopIgfsOutputStream extends OutputStream implements HadoopIgfsStreamEventListener { /** Log instance. */ private Log log; /** Client logger. */ private IgfsLogger clientLog; /** Log stream ID. */ private long logStreamId; /** Server stream delegate. */ private HadoopIgfsStreamDelegate delegate; /** Closed flag. */ private volatile boolean closed; /** Flag set if stream was closed due to connection breakage. */ private boolean connBroken; /** Error message. */ private volatile String errMsg; /** Read time. */ private long writeTime; /** User time. */ private long userTime; /** Last timestamp. */ private long lastTs; /** Amount of written bytes. */ private long total; /** * Creates light output stream. * * @param delegate Server stream delegate. * @param log Logger to use. * @param clientLog Client logger. */ public HadoopIgfsOutputStream(HadoopIgfsStreamDelegate delegate, Log log, IgfsLogger clientLog, long logStreamId) { this.delegate = delegate; this.log = log; this.clientLog = clientLog; this.logStreamId = logStreamId; lastTs = System.nanoTime(); delegate.hadoop().addEventListener(delegate, this); } /** * Read start. */ private void writeStart() { long now = System.nanoTime(); userTime += now - lastTs; lastTs = now; } /** * Read end. */ private void writeEnd() { long now = System.nanoTime(); writeTime += now - lastTs; lastTs = now; } /** {@inheritDoc} */ @Override public void write(@NotNull byte[] b, int off, int len) throws IOException { check(); writeStart(); try { delegate.hadoop().writeData(delegate, b, off, len); total += len; } finally { writeEnd(); } } /** {@inheritDoc} */ @Override public void write(int b) throws IOException { write(new byte[] { (byte) b }); total++; } /** {@inheritDoc} */ @Override public void flush() throws IOException { delegate.hadoop().flush(delegate); } /** {@inheritDoc} */ @Override public void close() throws IOException { if (!closed) { if (log.isDebugEnabled()) log.debug("Closing output stream: " + delegate); writeStart(); delegate.hadoop().closeStream(delegate); markClosed(false); writeEnd(); if (clientLog.isLogEnabled()) clientLog.logCloseOut(logStreamId, userTime, writeTime, total); if (log.isDebugEnabled()) log.debug("Closed output stream [delegate=" + delegate + ", writeTime=" + writeTime / 1000 + ", userTime=" + userTime / 1000 + ']'); } else if (connBroken) throw new IOException( "Failed to close stream, because connection was broken (data could have been lost)."); } /** * Marks stream as closed. * * @param connBroken {@code True} if connection with server was lost. */ private void markClosed(boolean connBroken) { // It is ok to have race here. if (!closed) { closed = true; delegate.hadoop().removeEventListener(delegate); this.connBroken = connBroken; } } /** * @throws IOException If check failed. */ private void check() throws IOException { String errMsg0 = errMsg; if (errMsg0 != null) throw new IOException(errMsg0); if (closed) { if (connBroken) throw new IOException("Server connection was lost."); else throw new IOException("Stream is closed."); } } /** {@inheritDoc} */ @Override public void onClose() throws IgniteCheckedException { markClosed(true); } /** {@inheritDoc} */ @Override public void onError(String errMsg) { this.errMsg = errMsg; } }