de.tudarmstadt.ukp.dkpro.core.io.xml.XmlReaderText.java Source code

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/*******************************************************************************
 * Copyright 2010
 * Ubiquitous Knowledge Processing (UKP) Lab
 * Technische Universitt 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.io.xml;

import static org.apache.commons.io.IOUtils.closeQuietly;

import java.io.IOException;
import java.io.InputStream;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.apache.uima.cas.CAS;
import org.apache.uima.cas.CASException;
import org.apache.uima.collection.CollectionException;
import org.apache.uima.fit.descriptor.TypeCapability;
import org.apache.uima.jcas.JCas;
import org.apache.uima.util.Logger;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import de.tudarmstadt.ukp.dkpro.core.api.io.ResourceCollectionReaderBase;

/**
 * @author Richard Eckart de Castilho
 * @since 1.1.0
 */
@TypeCapability(outputs = { "de.tudarmstadt.ukp.dkpro.core.api.metadata.type.DocumentMetaData" })

public class XmlReaderText extends ResourceCollectionReaderBase {
    @Override
    public void getNext(CAS aCAS) throws IOException, CollectionException {
        Resource res = nextFile();
        initCas(aCAS, res);

        InputStream is = null;

        try {
            JCas jcas = aCAS.getJCas();

            is = res.getInputStream();

            // Create handler
            Handler handler = newSaxHandler();
            handler.setJCas(jcas);
            handler.setLogger(getLogger());

            // Parser XML
            SAXParserFactory pf = SAXParserFactory.newInstance();
            SAXParser parser = pf.newSAXParser();

            InputSource source = new InputSource(is);
            source.setPublicId(res.getLocation());
            source.setSystemId(res.getLocation());
            parser.parse(source, handler);

            // Set up language
            if (getConfigParameterValue(PARAM_LANGUAGE) != null) {
                aCAS.setDocumentLanguage((String) getConfigParameterValue(PARAM_LANGUAGE));
            }
        } catch (CASException e) {
            throw new CollectionException(e);
        } catch (ParserConfigurationException e) {
            throw new CollectionException(e);
        } catch (SAXException e) {
            throw new IOException(e);
        } finally {
            closeQuietly(is);
        }
    }

    protected Handler newSaxHandler() {
        return new TextExtractor();
    }

    /**
     * @author Richard Eckart de Castilho
     */
    protected abstract static class Handler extends DefaultHandler {
        private JCas jcas;
        private Logger logger;

        public void setJCas(final JCas aJCas) {
            jcas = aJCas;
        }

        protected JCas getJCas() {
            return jcas;
        }

        public void setLogger(Logger aLogger) {
            logger = aLogger;
        }

        public Logger getLogger() {
            return logger;
        }
    }

    /**
     * @author Richard Eckart de Castilho
     */
    public static class TextExtractor extends Handler {
        private final StringBuilder buffer = new StringBuilder();

        @Override
        public void characters(char[] aCh, int aStart, int aLength) throws SAXException {
            buffer.append(aCh, aStart, aLength);
        }

        @Override
        public void ignorableWhitespace(char[] aCh, int aStart, int aLength) throws SAXException {
            buffer.append(aCh, aStart, aLength);
        }

        @Override
        public void endDocument() throws SAXException {
            getJCas().setDocumentText(buffer.toString());
        }

        protected StringBuilder getBuffer() {
            return buffer;
        }
    }
}