OpenNlpTrainerBase.java

/*
 * Copyright 2016
 * Ubiquitous Knowledge Processing (UKP) Lab
 * Technische Universität Darmstadt
 *
 * 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 de.tudarmstadt.ukp.dkpro.core.opennlp.internal;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

import org.apache.uima.UimaContext;
import org.apache.uima.analysis_engine.AnalysisEngineProcessException;
import org.apache.uima.fit.component.JCasConsumer_ImplBase;
import org.apache.uima.fit.descriptor.ConfigurationParameter;
import org.apache.uima.jcas.JCas;
import org.apache.uima.resource.ResourceInitializationException;

import de.tudarmstadt.ukp.dkpro.core.api.parameter.ComponentParameters;
import opennlp.tools.util.model.BaseModel;

/**
 * Train a model for OpenNLP.
 */
public abstract class OpenNlpTrainerBase<T extends CasSampleStreamBase>
    extends JCasConsumer_ImplBase
{
    public static final String PARAM_TARGET_LOCATION = ComponentParameters.PARAM_TARGET_LOCATION;
    @ConfigurationParameter(name = PARAM_TARGET_LOCATION, mandatory = true)
    private File targetLocation;

    private T stream;
    private ExecutorService executor = Executors.newSingleThreadExecutor();
    private Future<? extends BaseModel> future;
    
    @Override
    public void initialize(UimaContext aContext)
        throws ResourceInitializationException
    {
        super.initialize(aContext);
        
        stream = makeSampleStream();
        
        Callable<? extends BaseModel> trainTask = makeTrainer();
        
        future = executor.submit(trainTask);
    }
    
    public abstract T makeSampleStream();
    
    public abstract Callable<? extends BaseModel> makeTrainer();
    
    public T getStream()
    {
        return stream;
    }
    
    @Override
    public void process(JCas aJCas)
        throws AnalysisEngineProcessException
    {
        if (!future.isCancelled()) {
            stream.send(aJCas);
        }
    }
    
    @Override
    public void collectionProcessComplete()
        throws AnalysisEngineProcessException
    {
        try {
            stream.close();
        }
        catch (IOException e) {
            throw new AnalysisEngineProcessException(e);
        }
        
        BaseModel model;
        try {
            model = future.get();
        }
        catch (InterruptedException | ExecutionException e) {
            throw new AnalysisEngineProcessException(e);
        }
        
        try (OutputStream out = new FileOutputStream(targetLocation)) {
            model.serialize(out);
        }
        catch (IOException e) {
            throw new AnalysisEngineProcessException(e);
        }
    }
}