View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.tika.detect;
18  
19  import java.io.InputStream;
20  
21  import org.apache.tika.metadata.Metadata;
22  import org.apache.tika.mime.MediaType;
23  
24  /**
25   * Content type detection based on a content type hint. This detector simply
26   * trusts any valid content type hint given in the input metadata, and returns
27   * that as the likely type of the input document.
28   *
29   * @since Apache Tika 0.3
30   */
31  public class TypeDetector implements Detector {
32  
33      /**
34       * Detects the content type of an input document based on a type hint
35       * given in the input metadata. The CONTENT_TYPE attribute of the given
36       * input metadata is expected to contain the type of the input document.
37       * If that attribute exists and contains a valid type name, then that
38       * type is returned.
39       *
40       * @param input ignored
41       * @param metadata input metadata, possibly with a CONTENT_TYPE value
42       * @return detected media type, or <code>application/octet-stream</code>
43       */
44      public MediaType detect(InputStream input, Metadata metadata) {
45          // Look for a type hint in the input metadata
46          String hint = metadata.get(Metadata.CONTENT_TYPE);
47          if (hint != null) {
48              MediaType type = MediaType.parse(hint);
49              if (type != null) {
50                  return type;
51              }
52          }
53          return MediaType.OCTET_STREAM;
54      }
55  
56  }