commit dbfb7adcc97e351d0ed72dd317e1e20ad419e09a

Author: Hairong Kuang <hairong@apache.org>
Date:   Thu Oct 14 20:35:53 2010 +0000

    HADOOP-6996. Allow CodecFactory to return a codec object given a codec' class name. Contributed by Hairong Kuang.
    
    
    git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1022697 13f79535-47bb-0310-9956-ffa450edef68


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/yahoo-merge@1079095 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -35,6 +35,9 @@ Trunk (unreleased changes)
 
     HADOOP-6889. Make RPC to have an option to timeout. (hairong)
 
+    HADOOP-6996. Allow CodecFactory to return a codec object given a codec'
+    class name. (hairong)
+
   IMPROVEMENTS
 
     HADOOP-6644. util.Shell getGROUPS_FOR_USER_COMMAND method name 

src/java/org/apache/hadoop/io/compress/CompressionCodecFactory.java

@@ -44,9 +44,15 @@ public class CompressionCodecFactory {
    */
   private SortedMap<String, CompressionCodec> codecs = null;
   
+  /**
+   * A map from class names to the codecs
+   */
+  private HashMap<String, CompressionCodec> codecsByClassName = null;
+
   private void addCodec(CompressionCodec codec) {
     String suffix = codec.getDefaultExtension();
     codecs.put(new StringBuilder(suffix).reverse().toString(), codec);
+    codecsByClassName.put(codec.getClass().getCanonicalName(), codec);
   }
   
   /**
@@ -135,6 +141,7 @@ public class CompressionCodecFactory {
    */
   public CompressionCodecFactory(Configuration conf) {
     codecs = new TreeMap<String, CompressionCodec>();
+    codecsByClassName = new HashMap<String, CompressionCodec>();
     List<Class<? extends CompressionCodec>> codecClasses = getCodecClasses(conf);
     if (codecClasses == null) {
       addCodec(new GzipCodec());
@@ -171,6 +178,18 @@ public class CompressionCodecFactory {
     return result;
   }
   
+  /**
+   * Find the relevant compression codec for the codec's canonical class name.
+   * @param classname the canonical class name of the codec
+   * @return the codec object
+   */
+  public CompressionCodec getCodecByClassName(String classname) {
+    if (codecsByClassName == null) {
+      return null;
+    }
+    return codecsByClassName.get(classname);
+  }
+
   /**
    * Removes a suffix from a filename, if it has it.
    * @param filename the filename to strip

src/test/core/org/apache/hadoop/io/compress/TestCodecFactory.java

@@ -124,28 +124,60 @@ public class TestCodecFactory extends TestCase {
       new CompressionCodecFactory(new Configuration());
     CompressionCodec codec = factory.getCodec(new Path("/tmp/foo.bar"));
     assertEquals("default factory foo codec", null, codec);
+    codec = factory.getCodecByClassName(BarCodec.class.getCanonicalName());
+    assertEquals("default factory foo codec", null, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo.gz"));
     checkCodec("default factory for .gz", GzipCodec.class, codec);
+    codec = factory.getCodecByClassName(GzipCodec.class.getCanonicalName());
+    checkCodec("default factory for gzip codec", GzipCodec.class, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo.bz2"));
     checkCodec("default factory for .bz2", BZip2Codec.class, codec);
+    codec = factory.getCodecByClassName(BZip2Codec.class.getCanonicalName());
+    checkCodec("default factory for bzip2 codec", BZip2Codec.class, codec);
+    
     factory = setClasses(new Class[0]);
     codec = factory.getCodec(new Path("/tmp/foo.bar"));
     assertEquals("empty codec bar codec", null, codec);
+    codec = factory.getCodecByClassName(BarCodec.class.getCanonicalName());
+    assertEquals("empty codec bar codec", null, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo.gz"));
     assertEquals("empty codec gz codec", null, codec);
+    codec = factory.getCodecByClassName(GzipCodec.class.getCanonicalName());
+    assertEquals("empty codec gz codec", null, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo.bz2"));
-    assertEquals("default factory for .bz2", null, codec);
+    assertEquals("empty factory for .bz2", null, codec);
+    codec = factory.getCodecByClassName(BZip2Codec.class.getCanonicalName());
+    assertEquals("empty factory for bzip2 codec", null, codec);
+    
     factory = setClasses(new Class[]{BarCodec.class, FooCodec.class, 
                                      FooBarCodec.class});
     codec = factory.getCodec(new Path("/tmp/.foo.bar.gz"));
     assertEquals("full factory gz codec", null, codec);
+    codec = factory.getCodecByClassName(GzipCodec.class.getCanonicalName());
+    assertEquals("full codec gz codec", null, codec);
+     
     codec = factory.getCodec(new Path("/tmp/foo.bz2"));
-    assertEquals("default factory for .bz2", null, codec);
+    assertEquals("full factory for .bz2", null, codec);
+    codec = factory.getCodecByClassName(BZip2Codec.class.getCanonicalName());
+    assertEquals("full codec bzip2 codec", null, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo.bar"));
     checkCodec("full factory bar codec", BarCodec.class, codec);
+    codec = factory.getCodecByClassName(BarCodec.class.getCanonicalName());
+    checkCodec("full factory bar codec", BarCodec.class, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo/baz.foo.bar"));
     checkCodec("full factory foo bar codec", FooBarCodec.class, codec);
+    codec = factory.getCodecByClassName(FooBarCodec.class.getCanonicalName());
+    checkCodec("full factory foo bar codec", FooBarCodec.class, codec);
+    
     codec = factory.getCodec(new Path("/tmp/foo.foo"));
     checkCodec("full factory foo codec", FooCodec.class, codec);
+    codec = factory.getCodecByClassName(FooCodec.class.getCanonicalName());
+    checkCodec("full factory foo codec", FooCodec.class, codec);
   }
 }