Counter.java
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上传日期:2018-01-08
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文件大小:4k
- /**
- * 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.hadoop.mapreduce;
- import java.io.IOException;
- import java.io.DataInput;
- import java.io.DataOutput;
- import org.apache.hadoop.io.Text;
- import org.apache.hadoop.io.Writable;
- import org.apache.hadoop.io.WritableUtils;
- /**
- * A named counter that tracks the progress of a map/reduce job.
- *
- * <p><code>Counters</code> represent global counters, defined either by the
- * Map-Reduce framework or applications. Each <code>Counter</code> is named by
- * an {@link Enum} and has a long for the value.</p>
- *
- * <p><code>Counters</code> are bunched into Groups, each comprising of
- * counters from a particular <code>Enum</code> class.
- */
- public class Counter implements Writable {
- private String name;
- private String displayName;
- private long value = 0;
-
- protected Counter() {
- }
- protected Counter(String name, String displayName) {
- this.name = name;
- this.displayName = displayName;
- }
-
- @Deprecated
- protected synchronized void setDisplayName(String displayName) {
- this.displayName = displayName;
- }
-
- /**
- * Read the binary representation of the counter
- */
- @Override
- public synchronized void readFields(DataInput in) throws IOException {
- name = Text.readString(in);
- if (in.readBoolean()) {
- displayName = Text.readString(in);
- } else {
- displayName = name;
- }
- value = WritableUtils.readVLong(in);
- }
-
- /**
- * Write the binary representation of the counter
- */
- @Override
- public synchronized void write(DataOutput out) throws IOException {
- Text.writeString(out, name);
- boolean distinctDisplayName = ! name.equals(displayName);
- out.writeBoolean(distinctDisplayName);
- if (distinctDisplayName) {
- Text.writeString(out, displayName);
- }
- WritableUtils.writeVLong(out, value);
- }
- public synchronized String getName() {
- return name;
- }
- /**
- * Get the name of the counter.
- * @return the user facing name of the counter
- */
- public synchronized String getDisplayName() {
- return displayName;
- }
-
- /**
- * What is the current value of this counter?
- * @return the current value
- */
- public synchronized long getValue() {
- return value;
- }
-
- /**
- * Increment this counter by the given value
- * @param incr the value to increase this counter by
- */
- public synchronized void increment(long incr) {
- value += incr;
- }
- @Override
- public synchronized boolean equals(Object genericRight) {
- if (genericRight instanceof Counter) {
- synchronized (genericRight) {
- Counter right = (Counter) genericRight;
- return name.equals(right.name) &&
- displayName.equals(right.displayName) &&
- value == right.value;
- }
- }
- return false;
- }
-
- @Override
- public synchronized int hashCode() {
- return name.hashCode() + displayName.hashCode();
- }
- }