org.springframework.batch.core.partition.support.MultiResourcePartitioner Maven / Gradle / Ivy
/*
* Copyright 2006-2013 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
*
* https://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.io.IOException;
import java.util.HashMap;
import java.util.Map;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
/**
* Implementation of {@link Partitioner} that locates multiple resources and
* associates their file names with execution context keys. Creates an
* {@link ExecutionContext} per resource, and labels them as
* {partition0, partition1, ..., partitionN}
. The grid size is
* ignored.
*
* @author Dave Syer
* @since 2.0
*/
public class MultiResourcePartitioner implements Partitioner {
private static final String DEFAULT_KEY_NAME = "fileName";
private static final String PARTITION_KEY = "partition";
private Resource[] resources = new Resource[0];
private String keyName = DEFAULT_KEY_NAME;
/**
* The resources to assign to each partition. In Spring configuration you
* can use a pattern to select multiple resources.
* @param resources the resources to use
*/
public void setResources(Resource[] resources) {
this.resources = resources;
}
/**
* The name of the key for the file name in each {@link ExecutionContext}.
* Defaults to "fileName".
* @param keyName the value of the key
*/
public void setKeyName(String keyName) {
this.keyName = keyName;
}
/**
* Assign the filename of each of the injected resources to an
* {@link ExecutionContext}.
*
* @see Partitioner#partition(int)
*/
@Override
public Map partition(int gridSize) {
Map map = new HashMap<>(gridSize);
int i = 0;
for (Resource resource : resources) {
ExecutionContext context = new ExecutionContext();
Assert.state(resource.exists(), "Resource does not exist: "+resource);
try {
context.putString(keyName, resource.getURL().toExternalForm());
}
catch (IOException e) {
throw new IllegalArgumentException("File could not be located for: "+resource, e);
}
map.put(PARTITION_KEY + i, context);
i++;
}
return map;
}
}