org.springframework.batch.item.file.transform.PassThroughFieldExtractor Maven / Gradle / Ivy
/*
* 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
*
* 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.item.file.transform;
import java.util.Collection;
import java.util.Map;
/**
* {@link FieldExtractor} that just returns the original item. If the item is an
* array or collection it will be returned as is, otherwise it is wrapped in a
* single element array.
*
* @author Dave Syer
*
*/
public class PassThroughFieldExtractor implements FieldExtractor {
/**
* Get an array of fields as close as possible to the input. The result
* depends on the type of the input:
*
* - A {@link FieldSet} or array will be returned as is
* - For a Collection the
toArray() method will be used
* - For a Map the
values() will be returned as an array
* - Otherwise it is wrapped in a single element array.
*
* Note that no attempt is made to sort the values, so passing in an
* unordered collection or map is probably a bad idea. Spring often gives
* you an ordered Map (e.g. if extracting data from a generic query using
* JDBC), so check the documentation for whatever is being used to generate
* the input.
*
* @param item the object to convert
* @return an array of objects as close as possible to the original item
*/
@Override
public Object[] extract(T item) {
if (item.getClass().isArray()) {
return (Object[]) item;
}
if (item instanceof Collection) {
return ((Collection) item).toArray();
}
if (item instanceof Map) {
return ((Map) item).values().toArray();
}
if (item instanceof FieldSet) {
return ((FieldSet) item).getValues();
}
return new Object[] { item };
}
}