Author: jukka
Date: Tue Jan 20 14:26:26 2009
New Revision: 736139
URL: http://svn.apache.org/viewvc?rev=736139&view=rev
Log:
TIKA-95: Pluggable magic header detectors
Documented NameDetector
Modified:
lucene/tika/trunk/src/main/java/org/apache/tika/detect/NameDetector.java
Modified:
lucene/tika/trunk/src/main/java/org/apache/tika/detect/NameDetector.java
URL:
http://svn.apache.org/viewvc/lucene/tika/trunk/src/main/java/org/apache/tika/detect/NameDetector.java?rev=736139&r1=736138&r2=736139&view=diff
==============================================================================
--- lucene/tika/trunk/src/main/java/org/apache/tika/detect/NameDetector.java
(original)
+++ lucene/tika/trunk/src/main/java/org/apache/tika/detect/NameDetector.java
Tue Jan 20 14:26:26 2009
@@ -26,18 +26,69 @@
import org.apache.tika.mime.MediaType;
/**
- *
- * @author Jukka Zitting
- *
+ * Content type detection based on the resource name. An instance of this
+ * class contains a set of regular expression patterns that are matched
+ * against the resource name potentially given as a part of the input metadata.
+ * <p>
+ * If a pattern matches the given name, then the media type associated with
+ * that pattern is returned as the likely content type of the input document.
+ * Otherwise the returned type is <code>application/octet-stream</code>.
+ * <p>
+ * See the {...@link #detect(InputStream, Metadata)} method for more details
+ * of the matching algorithm.
*/
public class NameDetector implements Detector {
+ /**
+ * The regular expression patterns used for type detection.
+ */
private final Map<Pattern, MediaType> patterns;
+ /**
+ * Creates a new content type detector based on the given name patterns.
+ * The given pattern map is not copied, so the caller may update the
+ * mappings even after this detector instance has been created. However,
+ * the map <em>must not be concurrently modified</em> while this instance
+ * is used for type detection.
+ *
+ * @param patterns map from name patterns to corresponding media types
+ */
public NameDetector(Map<Pattern, MediaType> patterns) {
this.patterns = patterns;
}
+ /**
+ * Detects the content type of an input document based on the document
+ * name given in the input metadata. The RESOURCE_NAME_KEY attribute of
+ * the given input metadata is expected to contain the name (normally
+ * a file name or a URL) of the input document.
+ * <p>
+ * If a resource name is given, then it is first processed as follows.
+ * <ol>
+ * <li>
+ * Potential URL query (?...) and fragment identifier (#...)
+ * parts are removed from the end of the resource name.
+ * </li>
+ * <li>
+ * Potential leading path elements (up to the last slash or backslash)
+ * are removed from the beginning of the resource name.
+ * </li>
+ * <li>
+ * Potential URL encodings (%nn, in UTF-8) are decoded.
+ * </li>
+ * <li>
+ * Any leading and trailing whitespace is removed.
+ * </li>
+ * </ol>
+ * <p>
+ * The resulting name string (if any) is then matched in sequence against
+ * all the configured name patterns. If a match is found, then the (first)
+ * matching media type is returned.
+ *
+ * @param input ignored
+ * @param metadata input metadata, possibly with a RESOURCE_NAME_KEY value
+ * @return detected media type, or <code>application/octet-stream</code>
+ */
public MediaType detect(InputStream input, Metadata metadata) {
// Look for a resource name in the input metadata
String name = metadata.get(Metadata.RESOURCE_NAME_KEY);
@@ -62,19 +113,19 @@
name = name.substring(backslash + 1);
}
+ // Decode any potential URL encoding
+ int percent = name.indexOf('%');
+ if (percent != -1) {
+ try {
+ name = URLDecoder.decode(name, "UTF-8");
+ } catch (UnsupportedEncodingException e) {
+ throw new AssertionError("UTF-8 not supported");
+ }
+ }
+
// Skip any leading or trailing whitespace
name = name.trim();
if (name.length() > 0) {
- // Decode any potential URL encoding
- int percent = name.indexOf('%');
- if (percent != -1) {
- try {
- name = URLDecoder.decode(name, "UTF-8");
- } catch (UnsupportedEncodingException e) {
- throw new AssertionError("UTF-8 not supported");
- }
- }
-
// Match the name against the registered patterns
for (Pattern pattern : patterns.keySet()) {
if (pattern.matcher(name).matches()) {
