TwoDArrayWritable.java
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上传日期:2018-01-08
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文件大小:3k
- /**
- * 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.io;
- import java.io.*;
- import java.lang.reflect.Array;
- /** A Writable for 2D arrays containing a matrix of instances of a class. */
- public class TwoDArrayWritable implements Writable {
- private Class valueClass;
- private Writable[][] values;
- public TwoDArrayWritable(Class valueClass) {
- this.valueClass = valueClass;
- }
- public TwoDArrayWritable(Class valueClass, Writable[][] values) {
- this(valueClass);
- this.values = values;
- }
- public Object toArray() {
- int dimensions[] = {values.length, 0};
- Object result = Array.newInstance(valueClass, dimensions);
- for (int i = 0; i < values.length; i++) {
- Object resultRow = Array.newInstance(valueClass, values[i].length);
- Array.set(result, i, resultRow);
- for (int j = 0; j < values[i].length; j++) {
- Array.set(resultRow, j, values[i][j]);
- }
- }
- return result;
- }
- public void set(Writable[][] values) { this.values = values; }
- public Writable[][] get() { return values; }
- public void readFields(DataInput in) throws IOException {
- // construct matrix
- values = new Writable[in.readInt()][];
- for (int i = 0; i < values.length; i++) {
- values[i] = new Writable[in.readInt()];
- }
- // construct values
- for (int i = 0; i < values.length; i++) {
- for (int j = 0; j < values[i].length; j++) {
- Writable value; // construct value
- try {
- value = (Writable)valueClass.newInstance();
- } catch (InstantiationException e) {
- throw new RuntimeException(e.toString());
- } catch (IllegalAccessException e) {
- throw new RuntimeException(e.toString());
- }
- value.readFields(in); // read a value
- values[i][j] = value; // store it in values
- }
- }
- }
- public void write(DataOutput out) throws IOException {
- out.writeInt(values.length); // write values
- for (int i = 0; i < values.length; i++) {
- out.writeInt(values[i].length);
- }
- for (int i = 0; i < values.length; i++) {
- for (int j = 0; j < values[i].length; j++) {
- values[i][j].write(out);
- }
- }
- }
- }