Choose.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.HashMap;
import java.util.Map;

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



/**
 * Corresponds to the <code><choose></code> tag.
 *
 * @author Christoph Böhme <c.boehme@dnb.de>,  Markus Michael Geipel
 *
 */
public final class Choose extends AbstractFlushingCollect {

	private String value;
	private String name;
	private int priority = Integer.MAX_VALUE;
	private final Map<NamedValueSource, Integer> priorities =
			new HashMap<NamedValueSource, Integer>();
	private int nextPriority;

	@Override
	protected void emit() {
		if(!isEmpty()){
			getNamedValueReceiver().receive(StringUtil.fallback(getName(), name),
					StringUtil.fallback(getValue(), value), this, getRecordCount(),
					getEntityCount());
		}
	}

	private boolean isEmpty() {
		return name == null;
	}

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

	@Override
	protected void clear() {
		value = null;
		name = null;
		priority = Integer.MAX_VALUE;
	}

	@Override
	protected void receive(final String name, final String value,
			final NamedValueSource source) {
		final int sourcePriority = priorities.get(source).intValue();
		if (sourcePriority <= priority) {
			this.value = value;
			this.name = name;
			this.priority = sourcePriority;
		}
	}

	@Override
	public void onNamedValueSourceAdded(final NamedValueSource namedValueSource) {
		priorities.put(namedValueSource, Integer.valueOf(nextPriority));
		nextPriority += 1;
	}

}