TripleCollect.java

/*
 * Copyright 2013, 2014, 2016 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.triples;

import org.culturegraph.mf.formeta.parser.FormetaParser;
import org.culturegraph.mf.formeta.parser.PartialRecordEmitter;
import org.culturegraph.mf.framework.FluxCommand;
import org.culturegraph.mf.framework.StreamReceiver;
import org.culturegraph.mf.framework.annotations.Description;
import org.culturegraph.mf.framework.annotations.In;
import org.culturegraph.mf.framework.annotations.Out;
import org.culturegraph.mf.framework.helpers.DefaultObjectPipe;
import org.culturegraph.mf.framework.objects.Triple;
import org.culturegraph.mf.framework.objects.Triple.ObjectType;

/**
 * Collects named values to form records. The name becomes the id, the value is
 * split by 'separator' into name and value
 *
 * @author markus geipel
 *
 */
@Description("Collects named values to form records. The name becomes the id, the value is split by 'separator' into name and value")
@In(Triple.class)
@Out(StreamReceiver.class)
@FluxCommand("collect-triples")
public final class TripleCollect extends DefaultObjectPipe<Triple, StreamReceiver> {

	private final FormetaParser parser = new FormetaParser();
	private final PartialRecordEmitter emitter = new PartialRecordEmitter();

	private String currentSubject;

	public TripleCollect() {
		parser.setEmitter(emitter);
	}

	@Override
	public void process(final Triple triple) {
		if (currentSubject == null) {
			currentSubject = triple.getSubject();
			getReceiver().startRecord(currentSubject);
		}

		if (currentSubject.equals(triple.getSubject())) {
			decodeTriple(triple);
		} else {
			getReceiver().endRecord();
			currentSubject = triple.getSubject();
			getReceiver().startRecord(currentSubject);
			decodeTriple(triple);
		}
	}

	public void decodeTriple(final Triple triple) {
		if(triple.getObjectType() == ObjectType.STRING){
			getReceiver().literal(triple.getPredicate(), triple.getObject());
		}else if (triple.getObjectType() == ObjectType.ENTITY){
			emitter.setDefaultName(triple.getPredicate());
			parser.parse(triple.getObject());
		}else{
			throw new UnsupportedOperationException(triple.getObjectType() + " can not yet be decoded");
		}
	}

	@Override
	protected void onResetStream() {
		if (currentSubject != null) {
			currentSubject = null;
			getReceiver().endRecord();
		}
	}

	@Override
	protected void onCloseStream() {
		if (currentSubject != null) {
			currentSubject = null;
			getReceiver().endRecord();
		}
	}

	@Override
	protected void onSetReceiver() {
		emitter.setReceiver(getReceiver());
	}

}