| 1 | /* |
| 2 | * Copyright 2006-2013 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.springframework.batch.core.partition.support; |
| 17 | |
| 18 | import java.util.Collection; |
| 19 | import java.util.Set; |
| 20 | |
| 21 | import org.springframework.batch.core.StepExecution; |
| 22 | import org.springframework.batch.core.partition.PartitionHandler; |
| 23 | import org.springframework.batch.core.partition.StepExecutionSplitter; |
| 24 | |
| 25 | /** |
| 26 | * Base {@link PartitionHandler} implementation providing common base |
| 27 | * features. Subclasses are expected to implement only the |
| 28 | * {@link #doHandle(org.springframework.batch.core.StepExecution, java.util.Set)} |
| 29 | * method which returns with the result of the execution(s) or an exception if |
| 30 | * the step failed to process. |
| 31 | * |
| 32 | * @author Sebastien Gerard |
| 33 | * @author Dave Syer |
| 34 | */ |
| 35 | public abstract class AbstractPartitionHandler implements PartitionHandler { |
| 36 | |
| 37 | private int gridSize = 1; |
| 38 | |
| 39 | /** |
| 40 | * Executes the specified {@link StepExecution} instances and returns an updated |
| 41 | * view of them. Throws an {@link Exception} if anything goes wrong. |
| 42 | * |
| 43 | * @param masterStepExecution the whole partition execution |
| 44 | * @param partitionStepExecutions the {@link StepExecution} instances to execute |
| 45 | * @return an updated view of these completed {@link StepExecution} instances |
| 46 | * @throws Exception if anything goes wrong. This allows implementations to |
| 47 | * be liberal and rely on the caller to translate an exception into a step |
| 48 | * failure as necessary. |
| 49 | */ |
| 50 | protected abstract Set<StepExecution> doHandle(StepExecution masterStepExecution, |
| 51 | Set<StepExecution> partitionStepExecutions) throws Exception; |
| 52 | |
| 53 | /** |
| 54 | * @see PartitionHandler#handle(StepExecutionSplitter, StepExecution) |
| 55 | */ |
| 56 | @Override |
| 57 | public Collection<StepExecution> handle(final StepExecutionSplitter stepSplitter, |
| 58 | final StepExecution masterStepExecution) throws Exception { |
| 59 | final Set<StepExecution> stepExecutions = stepSplitter.split(masterStepExecution, gridSize); |
| 60 | |
| 61 | return doHandle(masterStepExecution, stepExecutions); |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Returns the number of step executions. |
| 66 | * |
| 67 | * @return the number of step executions |
| 68 | */ |
| 69 | public int getGridSize() { |
| 70 | return gridSize; |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Passed to the {@link StepExecutionSplitter} in the |
| 75 | * {@link #handle(StepExecutionSplitter, StepExecution)} method, instructing |
| 76 | * it how many {@link StepExecution} instances are required, ideally. The |
| 77 | * {@link StepExecutionSplitter} is allowed to ignore the grid size in the |
| 78 | * case of a restart, since the input data partitions must be preserved. |
| 79 | * |
| 80 | * @param gridSize the number of step executions that will be created |
| 81 | */ |
| 82 | public void setGridSize(int gridSize) { |
| 83 | this.gridSize = gridSize; |
| 84 | } |
| 85 | |
| 86 | } |
| 87 | |