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 * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * 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.distributedlog.service.placement; import static com.google.common.base.Charsets.UTF_8; import java.io.IOException; import java.io.UnsupportedEncodingException; import org.apache.commons.lang3.builder.HashCodeBuilder; import org.apache.thrift.TException; import org.apache.thrift.protocol.TJSONProtocol; import org.apache.thrift.transport.TMemoryBuffer; import org.apache.thrift.transport.TMemoryInputTransport; /** * An object represent the load of a stream. * * <p>A comparable data object containing the identifier of the stream and the appraised load produced * by the stream. */ public class StreamLoad implements Comparable { private static final int BUFFER_SIZE = 4096; public final String stream; private final int load; public StreamLoad(String stream, int load) { this.stream = stream; this.load = load; } public int getLoad() { return load; } public String getStream() { return stream; } protected org.apache.distributedlog.service.placement.thrift.StreamLoad toThrift() { org.apache.distributedlog.service.placement.thrift.StreamLoad tStreamLoad = new org.apache.distributedlog.service.placement.thrift.StreamLoad(); return tStreamLoad.setStream(stream).setLoad(load); } public byte[] serialize() throws IOException { TMemoryBuffer transport = new TMemoryBuffer(BUFFER_SIZE); TJSONProtocol protocol = new TJSONProtocol(transport); try { toThrift().write(protocol); transport.flush(); return transport.toString(UTF_8.name()).getBytes(UTF_8); } catch (TException e) { throw new IOException("Failed to serialize stream load : ", e); } catch (UnsupportedEncodingException uee) { throw new IOException("Failed to serialize stream load : ", uee); } } public static StreamLoad deserialize(byte[] data) throws IOException { org.apache.distributedlog.service.placement.thrift.StreamLoad tStreamLoad = new org.apache.distributedlog.service.placement.thrift.StreamLoad(); TMemoryInputTransport transport = new TMemoryInputTransport(data); TJSONProtocol protocol = new TJSONProtocol(transport); try { tStreamLoad.read(protocol); return new StreamLoad(tStreamLoad.getStream(), tStreamLoad.getLoad()); } catch (TException e) { throw new IOException("Failed to deserialize stream load : ", e); } } @Override public int compareTo(Object o) { StreamLoad other = (StreamLoad) o; if (load == other.getLoad()) { return stream.compareTo(other.getStream()); } else { return Long.compare(load, other.getLoad()); } } @Override public boolean equals(Object o) { if (!(o instanceof StreamLoad)) { return false; } StreamLoad other = (StreamLoad) o; return stream.equals(other.getStream()) && load == other.getLoad(); } @Override public String toString() { return String.format("StreamLoad<Stream: %s, Load: %d>", stream, load); } @Override public int hashCode() { return new HashCodeBuilder().append(stream).append(load).build(); } }