ExternalWritable.java
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上传日期:2018-01-08
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文件大小:2k
- /**
- * 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 testjar;
- import java.io.DataInput;
- import java.io.DataOutput;
- import java.io.IOException;
- import org.apache.hadoop.io.WritableComparable;
- /**
- * This is an example simple writable class. This is used as a class external
- * to the Hadoop IO classes for testing of user Writable classes.
- *
- */
- public class ExternalWritable
- implements WritableComparable {
- private String message = null;
-
- public ExternalWritable() {
-
- }
-
- public ExternalWritable(String message) {
- this.message = message;
- }
-
- public String getMessage() {
- return message;
- }
- public void setMessage(String message) {
- this.message = message;
- }
- public void readFields(DataInput in)
- throws IOException {
-
- message = null;
- boolean hasMessage = in.readBoolean();
- if (hasMessage) {
- message = in.readUTF();
- }
- }
- public void write(DataOutput out)
- throws IOException {
-
- boolean hasMessage = (message != null && message.length() > 0);
- out.writeBoolean(hasMessage);
- if (hasMessage) {
- out.writeUTF(message);
- }
- }
-
- public int compareTo(Object o) {
-
- if (!(o instanceof ExternalWritable)) {
- throw new IllegalArgumentException("Input not an ExternalWritable");
- }
-
- ExternalWritable that = (ExternalWritable)o;
- return this.message.compareTo(that.message);
- }
- public String toString() {
- return this.message;
- }
- }