Range.java

/*
 * Copyright 2013, 2014 Deutsche Nationalbibliothek
 *
 * 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.culturegraph.mf.metamorph.collectors;

import java.util.Comparator;
import java.util.SortedSet;
import java.util.TreeSet;

import org.culturegraph.mf.metamorph.api.NamedValueSource;
import org.culturegraph.mf.metamorph.api.helpers.AbstractFlushingCollect;


/**
 * Corresponds to the <code><range></code> tag.
 *
 * @author Christoph Böhme
 */
public final class Range extends AbstractFlushingCollect {

	private final SortedSet<Integer> values = new TreeSet<Integer>(new IncrementDependingComparator());

	private int increment;
	private Integer first;

	/**
	 * A comparator which defines the sort order of the values in the range
	 * depending on the increment.
	 */
	private class IncrementDependingComparator implements Comparator<Integer> {

		@Override
		public int compare(final Integer o1, final Integer o2) {
			return Integer.signum(increment) * (o1 - o2);
		}

	}

	public int getIncrement() {
		return increment;
	}

	public void setIncrement(final int increment) {
		this.increment = increment;
	}

	@Override
	protected void emit() {
		for (final Integer i: values) {
			getNamedValueReceiver().receive(getName(), i.toString(), this, getRecordCount(), getEntityCount());
		}
	}

	@Override
	protected boolean isComplete() {
		return false;
	}

	@Override
	protected void receive(final String name, final String value, final NamedValueSource source) {
		if (first == null) {
			first = Integer.valueOf(value);
		} else {
			final int last = Integer.valueOf(value).intValue();
			for (int i = first.intValue(); (increment > 0 && i <= last) || (increment < 0 && i >= last); i += increment) {
				values.add(Integer.valueOf(i));
			}
			first = null;
		}
	}

	@Override
	protected void clear() {
		values.clear();
		first = null;
	}

}