/*
* 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.mime;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;
/**
* Registry of known Internet media types.
*/
public class MediaTypeRegistry implements Serializable {
/** Serial version UID */
private static final long serialVersionUID = 4710974869988895410L;
/**
* Returns the built-in media type registry included in Tika.
*
* @since Apache Tika 0.8
* @return default media type registry
*/
public static MediaTypeRegistry getDefaultRegistry() {
return MimeTypes.getDefaultMimeTypes().getMediaTypeRegistry();
}
/**
* Registry of known media types, including type aliases. A canonical
* media type is handled as an identity mapping, while an alias is stored
* as a mapping from the alias to the corresponding canonical type.
*/
private final Map<MediaType, MediaType> registry =
new HashMap<MediaType, MediaType>();
/**
* Known type inheritance relationships. The mapping is from a media type
* to the closest supertype.
*/
private final Map<MediaType, MediaType> inheritance =
new HashMap<MediaType, MediaType>();
/**
* Returns the set of all known canonical media types. Type aliases are
* not included in the returned set.
*
* @since Apache Tika 0.8
* @return canonical media types
*/
public SortedSet<MediaType> getTypes() {
return new TreeSet<MediaType>(registry.values());
}
/**
* Returns the set of known aliases of the given canonical media type.
*
* @since Apache Tika 0.8
* @param type canonical media type
* @return known aliases
*/
public SortedSet<MediaType> getAliases(MediaType type) {
SortedSet<MediaType> aliases = new TreeSet<MediaType>();
for (Map.Entry<MediaType, MediaType> entry : registry.entrySet()) {
if (entry.getValue().equals(type) && !entry.getKey().equals(type)) {
aliases.add(entry.getKey());
}
}
return aliases;
}
/**
* Returns the set of known children of the given canonical media type
*
* @since Apache Tika 1.8
* @param type canonical media type
* @return known children
*/
public SortedSet<MediaType> getChildTypes(MediaType type) {
SortedSet<MediaType> children = new TreeSet<MediaType>();
for (Map.Entry<MediaType, MediaType> entry : inheritance.entrySet()) {
if (entry.getValue().equals(type)) {
children.add(entry.getKey());
}
}
return children;
}
public void addType(MediaType type) {
registry.put(type, type);
}
public void addAlias(MediaType type, MediaType alias) {
registry.put(alias, type);
}
public void addSuperType(MediaType type, MediaType supertype) {
inheritance.put(type, supertype);
}
public MediaType normalize(MediaType type) {
if (type == null) {
return null;
}
MediaType canonical = registry.get(type.getBaseType());
if (canonical == null) {
return type;
} else if (type.hasParameters()) {
return new MediaType(canonical, type.getParameters());
} else {
return canonical;
}
}
/**
* Checks whether the given media type a is a specialization of a more
* generic type b. Both types should be already normalised.
*
* @since Apache Tika 0.8
* @param a media type, normalised
* @param b suspected supertype, normalised
* @return <code>true</code> if b is a supertype of a,
* <code>false</code> otherwise
*/
public boolean isSpecializationOf(MediaType a, MediaType b) {
return isInstanceOf(getSupertype(a), b);
}
/**
* Checks whether the given media type equals the given base type or
* is a specialization of it. Both types should be already normalised.
*
* @since Apache Tika 1.2
* @param a media type, normalised
* @param b base type, normalised
* @return <code>true</code> if b equals a or is a specialization of it,
* <code>false</code> otherwise
*/
public boolean isInstanceOf(MediaType a, MediaType b) {
return a != null && (a.equals(b) || isSpecializationOf(a, b));
}
/**
* Parses and normalises the given media type string and checks whether
* the result equals the given base type or is a specialization of it.
* The given base type should already be normalised.
*
* @since Apache Tika 1.2
* @param a media type
* @param b base type, normalised
* @return <code>true</code> if b equals a or is a specialization of it,
* <code>false</code> otherwise
*/
public boolean isInstanceOf(String a, MediaType b) {
return isInstanceOf(normalize(MediaType.parse(a)), b);
}
/**
* Returns the supertype of the given type. If the media type database
* has an explicit inheritance rule for the type, then that is used.
* Next, if the given type has any parameters, then the respective base
* type (parameter-less) is returned. Otherwise built-in heuristics like
* text/... -> text/plain and .../...+xml -> application/xml are used.
* Finally application/octet-stream is returned for all types for which no other
* supertype is known, and the return value for application/octet-stream
* is <code>null</code>.
*
* @since Apache Tika 0.8
* @param type media type
* @return supertype, or <code>null</code> for application/octet-stream
*/
public MediaType getSupertype(MediaType type) {
if (type == null) {
return null;
} else if (inheritance.containsKey(type)) {
return inheritance.get(type);
} else if (type.hasParameters()) {
return type.getBaseType();
} else if (type.getSubtype().endsWith("+xml")) {
return MediaType.APPLICATION_XML;
} else if (type.getSubtype().endsWith("+zip")) {
return MediaType.APPLICATION_ZIP;
} else if ("text".equals(type.getType())
&& !MediaType.TEXT_PLAIN.equals(type)) {
return MediaType.TEXT_PLAIN;
} else if(type.getType().contains("empty") && !MediaType.EMPTY.equals(type)){
return MediaType.EMPTY;
} else if (!MediaType.OCTET_STREAM.equals(type)) {
return MediaType.OCTET_STREAM;
} else {
return null;
}
}
}