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.DataOutput; import java.io.IOException; import org.apache.hadoop.io.Writable; import com.alicloud.openservices.tablestore.model.ColumnValue; import com.alicloud.openservices.tablestore.model.Column; import com.alicloud.openservices.tablestore.core.utils.Preconditions; public class ColumnWritable implements Writable { private Column column = null; public ColumnWritable() { } public ColumnWritable(Column col) { Preconditions.checkNotNull(col, "The column should not be null."); column = col; } public Column getColumn() { return column; } @Override public void write(DataOutput out) throws IOException { Preconditions.checkNotNull(column, "column should not be null."); if (column.hasSetTimestamp()) { out.writeByte(WritableConsts.COLUMN_WITH_TIMESTAMP); } else { out.writeByte(WritableConsts.COLUMN_WITHOUT_TIMESTAMP); } out.writeUTF(column.getName()); new ColumnValueWritable(column.getValue()).write(out); if (column.hasSetTimestamp()) { out.writeLong(column.getTimestamp()); } } @Override public void readFields(DataInput in) throws IOException { byte tagColumn = in.readByte(); if (tagColumn == WritableConsts.COLUMN_WITHOUT_TIMESTAMP) { String name = in.readUTF(); ColumnValue val = ColumnValueWritable.read(in).getColumnValue(); column = new Column(name, val); } else if (tagColumn == WritableConsts.COLUMN_WITH_TIMESTAMP) { String name = in.readUTF(); ColumnValue val = ColumnValueWritable.read(in).getColumnValue(); long ts = in.readLong(); column = new Column(name, val, ts); } else { throw new IOException("broken input stream"); } } public static ColumnWritable read(DataInput in) throws IOException { ColumnWritable w = new ColumnWritable(); w.readFields(in); return w; } }