/*
* Copyright 2006-2007 the original author or authors.
*
* 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 org.springframework.batch.core.partition.support;
import java.util.Map;
import org.springframework.batch.item.ExecutionContext;
/**
* Central strategy interface for creating input parameters for a partitioned
* step in the form of {@link ExecutionContext} instances. The usual aim is to
* create a set of distinct input values, e.g. a set of non-overlapping primary
* key ranges, or a set of unique filenames.
*
* @author Dave Syer
* @since 2.0
*/
public interface Partitioner {
/**
* Create a set of distinct {@link ExecutionContext} instances together with
* a unique identifier for each one. The identifiers should be short,
* mnemonic values, and only have to be unique within the return value (e.g.
* use an incrementer).
*
* @param gridSize the size of the map to return
* @return a map from identifier to input parameters
*/
Map<String, ExecutionContext> partition(int gridSize);
}