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.util.List; import java.util.ArrayList; import java.io.DataInput; import java.io.DataOutput; import java.io.ObjectInput; import java.io.ObjectOutput; import java.io.IOException; import java.io.Externalizable; import org.apache.hadoop.io.Writable; import com.alicloud.openservices.tablestore.model.RowChange; import com.alicloud.openservices.tablestore.model.RowPutChange; import com.alicloud.openservices.tablestore.model.RowUpdateChange; import com.alicloud.openservices.tablestore.model.RowDeleteChange; import com.alicloud.openservices.tablestore.core.utils.Preconditions; public class BatchWriteWritable implements Writable, Externalizable { private List<RowChange> changes = new ArrayList<RowChange>(); public BatchWriteWritable() { } public void addRowChange(RowChange row) { Preconditions.checkNotNull(row, "row must be nonnull."); this.changes.add(row); } public List<RowChange> getRowChanges() { return this.changes; } @Override public void write(DataOutput out) throws IOException { out.writeByte(WritableConsts.BATCH_WRITE); out.writeInt(this.changes.size()); for (int i = 0; i < this.changes.size(); ++i) { RowChange rowChange = this.changes.get(i); if (rowChange instanceof RowPutChange) { out.writeByte(WritableConsts.PUT_ROW); new RowPutChangeWritable((RowPutChange) rowChange).write(out); } else if (rowChange instanceof RowDeleteChange) { out.writeByte(WritableConsts.DELETE_ROW); new RowDeleteChangeWritable((RowDeleteChange) rowChange).write(out); } else if (rowChange instanceof RowUpdateChange) { out.writeByte(WritableConsts.UPDATE_ROW); new RowUpdateChangeWritable((RowUpdateChange) rowChange).write(out); } else { throw new AssertionError("unsupported RowChange type: " + rowChange.getClass().getName()); } } } @Override public void readFields(DataInput in) throws IOException { byte tagBatchWrite = in.readByte(); if (tagBatchWrite != WritableConsts.BATCH_WRITE) { throw new IOException("broken input stream"); } List<RowChange> changes = new ArrayList<RowChange>(); int rowSz = in.readInt(); for (int i = 0; i < rowSz; ++i) { byte tagRow = in.readByte(); if (tagRow == WritableConsts.PUT_ROW) { changes.add(RowPutChangeWritable.read(in).getRowPutChange()); } else if (tagRow == WritableConsts.DELETE_ROW) { changes.add(RowDeleteChangeWritable.read(in).getRowDeleteChange()); } else if (tagRow == WritableConsts.UPDATE_ROW) { changes.add(RowUpdateChangeWritable.read(in).getRowUpdateChange()); } else { throw new IOException("broken input stream"); } } this.changes = changes; } public static BatchWriteWritable read(DataInput in) throws IOException { BatchWriteWritable w = new BatchWriteWritable(); 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); } }