Reporter.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.mapred;
- import org.apache.hadoop.mapred.Counters.Counter;
- import org.apache.hadoop.util.Progressable;
- /**
- * A facility for Map-Reduce applications to report progress and update
- * counters, status information etc.
- *
- * <p>{@link Mapper} and {@link Reducer} can use the <code>Reporter</code>
- * provided to report progress or just indicate that they are alive. In
- * scenarios where the application takes an insignificant amount of time to
- * process individual key/value pairs, this is crucial since the framework
- * might assume that the task has timed-out and kill that task.
- *
- * <p>Applications can also update {@link Counters} via the provided
- * <code>Reporter</code> .</p>
- *
- * @see Progressable
- * @see Counters
- */
- public interface Reporter extends Progressable {
-
- /**
- * A constant of Reporter type that does nothing.
- */
- public static final Reporter NULL = new Reporter() {
- public void setStatus(String s) {
- }
- public void progress() {
- }
- public Counter getCounter(Enum<?> name) {
- return null;
- }
- public Counter getCounter(String group, String name) {
- return null;
- }
- public void incrCounter(Enum<?> key, long amount) {
- }
- public void incrCounter(String group, String counter, long amount) {
- }
- public InputSplit getInputSplit() throws UnsupportedOperationException {
- throw new UnsupportedOperationException("NULL reporter has no input");
- }
- };
- /**
- * Set the status description for the task.
- *
- * @param status brief description of the current status.
- */
- public abstract void setStatus(String status);
-
- /**
- * Get the {@link Counter} of the given group with the given name.
- *
- * @param name counter name
- * @return the <code>Counter</code> of the given group/name.
- */
- public abstract Counter getCounter(Enum<?> name);
- /**
- * Get the {@link Counter} of the given group with the given name.
- *
- * @param group counter group
- * @param name counter name
- * @return the <code>Counter</code> of the given group/name.
- */
- public abstract Counter getCounter(String group, String name);
-
- /**
- * Increments the counter identified by the key, which can be of
- * any {@link Enum} type, by the specified amount.
- *
- * @param key key to identify the counter to be incremented. The key can be
- * be any <code>Enum</code>.
- * @param amount A non-negative amount by which the counter is to
- * be incremented.
- */
- public abstract void incrCounter(Enum<?> key, long amount);
-
- /**
- * Increments the counter identified by the group and counter name
- * by the specified amount.
- *
- * @param group name to identify the group of the counter to be incremented.
- * @param counter name to identify the counter within the group.
- * @param amount A non-negative amount by which the counter is to
- * be incremented.
- */
- public abstract void incrCounter(String group, String counter, long amount);
-
- /**
- * Get the {@link InputSplit} object for a map.
- *
- * @return the <code>InputSplit</code> that the map is reading from.
- * @throws UnsupportedOperationException if called outside a mapper
- */
- public abstract InputSplit getInputSplit()
- throws UnsupportedOperationException;
- }