/*
* Copyright 2010
* 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.io.pdf;
import static org.apache.commons.io.IOUtils.closeQuietly;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import org.apache.uima.UimaContext;
import org.apache.uima.cas.CAS;
import org.apache.uima.collection.CollectionException;
import org.apache.uima.fit.descriptor.ConfigurationParameter;
import org.apache.uima.fit.descriptor.MimeTypeCapability;
import org.apache.uima.fit.descriptor.TypeCapability;
import org.apache.uima.resource.ResourceInitializationException;
import de.tudarmstadt.ukp.dkpro.core.api.io.ResourceCollectionReaderBase;
import de.tudarmstadt.ukp.dkpro.core.api.parameter.MimeTypes;
import de.tudarmstadt.ukp.dkpro.core.api.resources.ResourceUtils;
import de.tudarmstadt.ukp.dkpro.core.api.segmentation.type.Heading;
import de.tudarmstadt.ukp.dkpro.core.api.segmentation.type.Paragraph;
/**
* Collection reader for PDF files. Uses simple heuristics to detect headings and paragraphs.
*/
@MimeTypeCapability({MimeTypes.APPLICATION_PDF})
@TypeCapability(
outputs = {
"de.tudarmstadt.ukp.dkpro.core.api.metadata.type.DocumentMetaData",
"de.tudarmstadt.ukp.dkpro.core.api.segmentation.type.Heading",
"de.tudarmstadt.ukp.dkpro.core.api.segmentation.type.Paragraph"})
public class PdfReader
extends ResourceCollectionReaderBase
{
public static final String BUILT_IN = "<built-in>";
private static final String NOT_RESTRICTED = "-1";
/**
* The location of the substitution table use to post-process the text extracted form the PDF,
* e.g. to convert ligatures to separate characters.
*/
public static final String PARAM_SUBSTITUTION_TABLE_LOCATION = "substitutionTableLocation";
@ConfigurationParameter(name = PARAM_SUBSTITUTION_TABLE_LOCATION, mandatory = false, defaultValue = BUILT_IN)
private String substitutionTableLocation;
/**
* The type used to annotate headings.
*/
public static final String PARAM_HEADING_TYPE = "headingType";
@ConfigurationParameter(name = PARAM_HEADING_TYPE, mandatory = false, defaultValue = BUILT_IN)
private String headingType;
/**
* The type used to annotate paragraphs.
*/
public static final String PARAM_PARAGRAPH_TYPE = "paragraphType";
@ConfigurationParameter(name = PARAM_PARAGRAPH_TYPE, mandatory = false, defaultValue = BUILT_IN)
private String paragraphType;
/**
* The first page to be extracted from the PDF.
*/
public static final String PARAM_START_PAGE = "startPage";
@ConfigurationParameter(name = PARAM_START_PAGE, mandatory = false, defaultValue = NOT_RESTRICTED)
private int startPage;
/**
* The last page to be extracted from the PDF.
*/
public static final String PARAM_END_PAGE = "endPage";
@ConfigurationParameter(name = PARAM_END_PAGE, mandatory = false, defaultValue = NOT_RESTRICTED)
private int endPage;
private Trie<String> substitutionTable;
@Override
public void initialize(UimaContext aContext)
throws ResourceInitializationException
{
super.initialize(aContext);
if (BUILT_IN.equals(headingType)) {
headingType = Heading.class.getName();
}
if (BUILT_IN.equals(paragraphType)) {
paragraphType = Paragraph.class.getName();
}
if (substitutionTableLocation != null) {
if (BUILT_IN.equals(substitutionTableLocation)) {
substitutionTableLocation = "classpath:/de/tudarmstadt/ukp/dkpro/core/io/pdf/substitutionTable.xml";
}
InputStream is = null;
try {
URL url = ResourceUtils.resolveLocation(substitutionTableLocation, this, aContext);
is = url.openStream();
substitutionTable = SubstitutionTrieParser.parse(is);
}
catch (IOException e) {
throw new ResourceInitializationException(e);
}
finally {
closeQuietly(is);
}
}
else {
substitutionTable = null;
}
}
@Override
public void getNext(CAS aCAS)
throws IOException, CollectionException
{
Resource resource = nextFile();
initCas(aCAS, resource, null);
InputStream is = null;
try {
is = resource.getInputStream();
final Pdf2CasConverter converter = new Pdf2CasConverter();
converter.setSubstitutionTable(substitutionTable);
converter.setHeadingType(headingType);
converter.setParagraphType(paragraphType);
if (startPage != Integer.parseInt(NOT_RESTRICTED)) {
converter.setStartPage(startPage);
}
if (endPage != Integer.parseInt(NOT_RESTRICTED)) {
converter.setEndPage(endPage);
}
converter.writeText(aCAS, is);
}
finally {
closeQuietly(is);
}
}
}