/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.tika.parser;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.tika.exception.TikaException;
import org.apache.tika.io.TaggedInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.sax.TaggedContentHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
/**
* Composite parser that delegates parsing tasks to a component parser
* based on the declared content type of the incoming document. A fallback
* parser is defined for cases where a parser for the given content type is
* not available.
*/
public class CompositeParser implements Parser {
/**
* Set of component parsers, keyed by the supported media types.
*/
private Map<String, Parser> parsers = new HashMap<String, Parser>();
/**
* The fallback parser, used when no better parser is available.
*/
private Parser fallback = new EmptyParser();
/**
* Returns the component parsers.
*
* @return component parsers, keyed by media type
*/
public Map<String, Parser> getParsers() {
return parsers;
}
/**
* Sets the component parsers.
*
* @param parsers component parsers, keyed by media type
*/
public void setParsers(Map<String, Parser> parsers) {
this.parsers = parsers;
}
/**
* Returns the fallback parser.
*
* @return fallback parser
*/
public Parser getFallback() {
return fallback;
}
/**
* Sets the fallback parser.
*
* @param fallback fallback parser
*/
public void setFallback(Parser fallback) {
this.fallback = fallback;
}
/**
* Returns the parser that best matches the given metadata. By default
* looks for a parser that matches the content type metadata property,
* and uses the fallback parser if a better match is not found.
* <p>
* Subclasses can override this method to provide more accurate
* parser resolution.
*
* @param metadata document metadata
* @return matching parser
*/
protected Parser getParser(Metadata metadata) {
Parser parser = parsers.get(metadata.get(Metadata.CONTENT_TYPE));
if (parser == null) {
parser = fallback;
}
return parser;
}
public Set<MediaType> getSupportedTypes(ParseContext context) {
Set<MediaType> supportedTypes = new HashSet<MediaType>();
for (String type : parsers.keySet()) {
supportedTypes.add(MediaType.parse(type));
}
return Collections.unmodifiableSet(supportedTypes);
}
/**
* Delegates the call to the matching component parser.
* <p>
* Potential {@link RuntimeException}s, {@link IOException}s and
* {@link SAXException}s unrelated to the given input stream and content
* handler are automatically wrapped into {@link TikaException}s to better
* honor the {@link Parser} contract.
*/
public void parse(
InputStream stream, ContentHandler handler,
Metadata metadata, ParseContext context)
throws IOException, SAXException, TikaException {
Parser parser = getParser(metadata);
TaggedInputStream taggedStream = new TaggedInputStream(stream);
TaggedContentHandler taggedHandler = new TaggedContentHandler(handler);
try {
parser.parse(taggedStream, taggedHandler, metadata, context);
} catch (RuntimeException e) {
throw new TikaException(
"Unexpected RuntimeException from " + parser, e);
} catch (IOException e) {
taggedStream.throwIfCauseOf(e);
throw new TikaException(
"TIKA-198: Illegal IOException from " + parser, e);
} catch (SAXException e) {
taggedHandler.throwIfCauseOf(e);
throw new TikaException(
"TIKA-237: Illegal SAXException from " + parser, e);
}
}
/**
* @deprecated This method will be removed in Apache Tika 1.0.
*/
public void parse(
InputStream stream, ContentHandler handler, Metadata metadata)
throws IOException, SAXException, TikaException {
parse(stream, handler, metadata, new ParseContext());
}
}