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 * * 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 com.aliyun.openservices.tablestore.hadoop; import java.io.DataInput; import java.io.ObjectInput; import java.io.DataOutput; import java.io.ObjectOutput; import java.io.IOException; import java.io.Externalizable; import org.apache.hadoop.io.Writable; import com.alicloud.openservices.tablestore.model.Row; import com.alicloud.openservices.tablestore.model.Column; import com.alicloud.openservices.tablestore.model.PrimaryKey; import com.alicloud.openservices.tablestore.core.utils.Preconditions; public class RowWritable implements Writable, Externalizable { private Row row = null; public RowWritable() { } public RowWritable(Row row) { Preconditions.checkNotNull(row, "row should not be null."); this.row = row; } public Row getRow() { return row; } public void setRow(Row row) { Preconditions.checkNotNull(row, "row should not be null."); this.row = row; } @Override public void write(DataOutput out) throws IOException { Preconditions.checkNotNull(row, "column should not be null."); out.writeByte(WritableConsts.ROW); new PrimaryKeyWritable(row.getPrimaryKey()).write(out); Column[] cols = row.getColumns(); out.writeInt(cols.length); for (int i = 0; i < cols.length; ++i) { new ColumnWritable(cols[i]).write(out); } } @Override public void readFields(DataInput in) throws IOException { byte tagRow = in.readByte(); if (tagRow != WritableConsts.ROW) { throw new IOException("broken input stream"); } PrimaryKey pkey = PrimaryKeyWritable.read(in).getPrimaryKey(); int sz = in.readInt(); Column[] cols = new Column[sz]; for (int i = 0; i < sz; ++i) { cols[i] = ColumnWritable.read(in).getColumn(); } row = new Row(pkey, cols); } public static RowWritable read(DataInput in) throws IOException { RowWritable w = new RowWritable(); w.readFields(in); return w; } @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException { this.readFields(in); } @Override public void writeExternal(ObjectOutput out) throws IOException { this.write(out); } }