| /* |
| * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved. |
| * |
| * Licensed 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.datatorrent.contrib.hbase; |
| |
| import org.apache.hadoop.hbase.KeyValue; |
| import org.apache.hadoop.hbase.client.Get; |
| import org.apache.hadoop.hbase.client.Result; |
| |
| /** |
| * A base implementation of hbase input operator that retrieves tuples from HBase columns and provides get operation. Subclasses should provide implementation for get operation. <br> |
| * <p> |
| * <br> |
| * This class provides a HBase input operator that can be used to retrieve tuples from columns in a |
| * HBase table. The class should be extended by the end-operator developer. The extending class should |
| * implement operationGet and getTuple methods. The operationGet method should provide a HBase Get metric |
| * object that specifies where to retrieve tuples from a table. The getTuple method should map the contents |
| * of a KeyValue from the Get result to a tuple.<br> |
| * |
| * <br> |
| * @displayName HBase Get |
| * @category Store |
| * @tags input operator, get |
| * @param <T> The tuple type |
| * @since 0.3.2 |
| */ |
| public abstract class HBaseGetOperator<T> extends HBaseInputOperator<T> |
| { |
| |
| @Override |
| public void emitTuples() |
| { |
| try { |
| Get get = operationGet(); |
| Result result = table.get(get); |
| KeyValue[] kvs = result.raw(); |
| //T t = getTuple(kvs); |
| //T t = getTuple(result); |
| for (KeyValue kv : kvs) { |
| T t = getTuple(kv); |
| outputPort.emit(t); |
| } |
| } catch (Exception e) { |
| throw new RuntimeException(e.getMessage()); |
| } |
| } |
| |
| /** |
| * Return a HBase Get metric to retrieve the tuple. |
| * The implementor should return a HBase Get metric that specifies where to retrieve the tuple from |
| * the table. |
| * |
| * @return The HBase Get metric |
| */ |
| protected abstract Get operationGet(); |
| |
| /** |
| * Get a tuple from a HBase Get result. |
| * The implementor should map the contents of a key value from a Get result and return a tuple. |
| * |
| * @param kv The key value |
| * @return The tuple |
| */ |
| protected abstract T getTuple(KeyValue kv); |
| |
| } |