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/*
* 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 org.apache.tika.exception.TikaException;
import org.apache.tika.io.TemporaryResources;
import org.apache.tika.io.TikaInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.mime.MediaTypeRegistry;
import org.apache.tika.sax.TaggedContentHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 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 extends AbstractParser {
/** Serial version UID */
private static final long serialVersionUID = 2192845797749627824L;
/**
* Media type registry.
*/
private MediaTypeRegistry registry;
/**
* List of component parsers.
*/
private List parsers;
/**
* The fallback parser, used when no better parser is available.
*/
private Parser fallback = new EmptyParser();
public CompositeParser(MediaTypeRegistry registry, List parsers,
Collection> excludeParsers) {
if (excludeParsers == null || excludeParsers.isEmpty()) {
this.parsers = parsers;
} else {
this.parsers = new ArrayList();
for (Parser p : parsers) {
if (!isExcluded(excludeParsers, p.getClass())) {
this.parsers.add(p);
}
}
}
this.registry = registry;
}
public CompositeParser(MediaTypeRegistry registry, List parsers) {
this(registry, parsers, null);
}
public CompositeParser(MediaTypeRegistry registry, Parser... parsers) {
this(registry, Arrays.asList(parsers));
}
public CompositeParser() {
this(new MediaTypeRegistry());
}
public Map getParsers(ParseContext context) {
Map map = new HashMap();
for (Parser parser : parsers) {
for (MediaType type : parser.getSupportedTypes(context)) {
map.put(registry.normalize(type), parser);
}
}
return map;
}
private boolean isExcluded(Collection> excludeParsers, Class p) {
return excludeParsers.contains(p) || assignableFrom(excludeParsers, p);
}
private boolean assignableFrom(Collection> excludeParsers, Class p) {
for (Class e : excludeParsers) {
if (e.isAssignableFrom(p)) return true;
}
return false;
}
/**
* Utility method that goes through all the component parsers and finds
* all media types for which more than one parser declares support. This
* is useful in tracking down conflicting parser definitions.
*
* @since Apache Tika 0.10
* @see TIKA-660
* @param context parsing context
* @return media types that are supported by at least two component parsers
*/
public Map> findDuplicateParsers(
ParseContext context) {
Map types = new HashMap();
Map> duplicates =
new HashMap>();
for (Parser parser : parsers) {
for (MediaType type : parser.getSupportedTypes(context)) {
MediaType canonicalType = registry.normalize(type);
if (types.containsKey(canonicalType)) {
List list = duplicates.get(canonicalType);
if (list == null) {
list = new ArrayList();
list.add(types.get(canonicalType));
duplicates.put(canonicalType, list);
}
list.add(parser);
} else {
types.put(canonicalType, parser);
}
}
}
return duplicates;
}
/**
* Returns the media type registry used to infer type relationships.
*
* @since Apache Tika 0.8
* @return media type registry
*/
public MediaTypeRegistry getMediaTypeRegistry() {
return registry;
}
/**
* Sets the media type registry used to infer type relationships.
*
* @since Apache Tika 0.8
* @param registry media type registry
*/
public void setMediaTypeRegistry(MediaTypeRegistry registry) {
this.registry = registry;
}
/**
* Returns all parsers registered with the Composite Parser,
* including ones which may not currently be active.
* This won't include the Fallback Parser, if defined
*/
public List getAllComponentParsers() {
return Collections.unmodifiableList(parsers);
}
/**
* Returns the component parsers.
*
* @return component parsers, keyed by media type
*/
public Map getParsers() {
return getParsers(new ParseContext());
}
/**
* Sets the component parsers.
*
* @param parsers component parsers, keyed by media type
*/
public void setParsers(Map parsers) {
this.parsers = new ArrayList(parsers.size());
for (Map.Entry entry : parsers.entrySet()) {
this.parsers.add(ParserDecorator.withTypes(
entry.getValue(), Collections.singleton(entry.getKey())));
}
}
/**
* 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. The
* type hierarchy information included in the configured media type
* registry is used when looking for a matching parser instance.
*
* Subclasses can override this method to provide more accurate
* parser resolution.
*
* @param metadata document metadata
* @return matching parser
*/
protected Parser getParser(Metadata metadata) {
return getParser(metadata, new ParseContext());
}
protected Parser getParser(Metadata metadata, ParseContext context) {
Map map = getParsers(context);
MediaType type = MediaType.parse(metadata.get(Metadata.CONTENT_TYPE));
if (type != null) {
// We always work on the normalised, canonical form
type = registry.normalize(type);
}
while (type != null) {
// Try finding a parser for the type
Parser parser = map.get(type);
if (parser != null) {
return parser;
}
// Failing that, try for the parent of the type
type = registry.getSupertype(type);
}
return fallback;
}
public Set getSupportedTypes(ParseContext context) {
return getParsers(context).keySet();
}
/**
* Delegates the call to the matching component parser.
*
* 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, context);
TemporaryResources tmp = new TemporaryResources();
try {
TikaInputStream taggedStream = TikaInputStream.get(stream, tmp);
TaggedContentHandler taggedHandler =
handler != null ? new TaggedContentHandler(handler) : null;
if (parser instanceof ParserDecorator){
metadata.add("X-Parsed-By", ((ParserDecorator) parser).getWrappedParser().getClass().getName());
} else {
metadata.add("X-Parsed-By", parser.getClass().getName());
}
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) {
if (taggedHandler != null) taggedHandler.throwIfCauseOf(e);
throw new TikaException(
"TIKA-237: Illegal SAXException from " + parser, e);
}
} finally {
tmp.dispose();
}
}
}