/*
* Copyright 2007 Kasper B. Graversen
*
* 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.supercsv.cellprocessor;
import java.util.Collection;
import org.supercsv.cellprocessor.ift.BoolCellProcessor;
import org.supercsv.cellprocessor.ift.CellProcessor;
import org.supercsv.cellprocessor.ift.DateCellProcessor;
import org.supercsv.cellprocessor.ift.DoubleCellProcessor;
import org.supercsv.cellprocessor.ift.LongCellProcessor;
import org.supercsv.cellprocessor.ift.StringCellProcessor;
import org.supercsv.util.CsvContext;
/**
* This processor collects each value it encounters and adds it to the supplied Collection. You could supply a Set to
* collect all of the unique values for a column, or a List to collect every value in a column in order. Just remember
* that the larger your CSV file, the larger this Collection will be, so use with caution!
*
* @since 2.1.0
* @author James Bassett
*/
public class Collector extends CellProcessorAdaptor implements BoolCellProcessor, DateCellProcessor,
DoubleCellProcessor, LongCellProcessor, StringCellProcessor {
private final Collection<Object> collection;
/**
* Constructs a new <tt>Collector</tt>, which collects each value it encounters and adds it to the supplied
* Collection.
*
* @param collection
* the collection to add to
* @throws NullPointerException
* if collection is null
*/
public Collector(final Collection<Object> collection) {
super();
checkPreconditions(collection);
this.collection = collection;
}
/**
* Constructs a new <tt>Collector</tt>, which collects each value it encounters, adds it to the supplied Collection,
* then calls the next processor in the chain.
*
* @param collection
* the collection to add to
* @param next
* the next processor in the chain
* @throws NullPointerException
* if collection or next is null
*/
public Collector(final Collection<Object> collection, final CellProcessor next) {
super(next);
checkPreconditions(collection);
this.collection = collection;
}
/**
* Checks the preconditions for creating a new Collector processor.
*
* @param collection
* the collection to add to
* @throws NullPointerException
* if collection is null
*/
private static void checkPreconditions(final Collection<Object> collection) {
if( collection == null ) {
throw new NullPointerException("collection should not be null");
}
}
/**
* {@inheritDoc}
*/
public Object execute(final Object value, final CsvContext context) {
collection.add(value);
return next.execute(value, context);
}
/**
* Gets the collection of collected values.
*
* @return the collection of collected values
*/
public Collection<Object> getCollection() {
return collection;
}
}
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