HBASE-1189 Changing the map type used internally for HbaseMapWritable

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@748256 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -61,6 +61,8 @@ Release 0.20.0 - Unreleased
                (Lars George via Stack)
    HBASE-1221  When using ant -projecthelp to build HBase not all the important
                options show up (Erik Holstad via Stack)
+   HBASE-1189  Changing the map type used internally for HbaseMapWritable
+               (Erik Holstad via Stack)
 
 Release 0.19.0 - 01/21/2009
   INCOMPATIBLE CHANGES

src/java/org/apache/hadoop/hbase/io/CodeToClassAndBack.java

@@ -0,0 +1,71 @@
+/**
+ * Copyright 2009 The Apache Software Foundation
+ *
+ * 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.hadoop.hbase.io;
+
+import java.util.*;
+
+/**
+ * A Static Interface.
+ * Instead of having this code in the the HbaseMapWritable code, where it
+ * blocks the possibility of altering the variables and changing their types,
+ * it is put here in this static interface where the static final Maps are
+ * loaded one time. Only byte[] and Cell are supported at this time.
+ */
+public interface CodeToClassAndBack {
+  /**
+   * Static map that contains mapping from code to class
+   */
+  public static final Map<Byte, Class<?>> CODE_TO_CLASS =
+    new HashMap<Byte, Class<?>>();
+
+  /**
+   * Static map that contains mapping from class to code
+   */
+  public static final Map<Class<?>, Byte> CLASS_TO_CODE =
+    new HashMap<Class<?>, Byte>();
+  
+  /**
+   * Class list for supported classes
+   */
+  public Class[] classList = {byte[].class, Cell.class};
+  
+  /**
+   * The static loader that is used instead of the static constructor in
+   * HbaseMapWritable.
+   */
+  public InternalStaticLoader sl =
+    new InternalStaticLoader(classList, CODE_TO_CLASS, CLASS_TO_CODE);
+
+  /**
+   * Class that loads the static maps with their values. 
+   */
+  public class InternalStaticLoader{
+    InternalStaticLoader(Class[] classList, Map<Byte, Class<?>> CODE_TO_CLASS,
+    Map<Class<?>, Byte> CLASS_TO_CODE){
+      byte code = 1;
+      for(int i=0; i<classList.length; i++){
+        CLASS_TO_CODE.put(classList[i], code);
+        CODE_TO_CLASS.put(code, classList[i]);
+        code++;
+      }
+    }
+  }
+}

src/java/org/apache/hadoop/hbase/io/HbaseMapWritable.java

@@ -24,7 +24,6 @@ import java.io.DataOutput;
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Comparator;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import java.util.SortedMap;
@@ -33,9 +32,7 @@ import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.hadoop.conf.Configurable;
 import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.hbase.HStoreKey;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.io.Text;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.util.ReflectionUtils;
 
@@ -48,37 +45,45 @@ import org.apache.hadoop.util.ReflectionUtils;
  * @param <K> <byte []> key  TODO: Parameter K is never used, could be removed.
  * @param <V> value Expects a Writable or byte [].
  */
-public class HbaseMapWritable <K, V>
+public class HbaseMapWritable <K,V>
-implements SortedMap<byte [], V>, Writable, Configurable {
+implements SortedMap<byte[],V>, Configurable, Writable,
-  private AtomicReference<Configuration> conf =
+  CodeToClassAndBack{
-    new AtomicReference<Configuration>();
+  
+  private AtomicReference<Configuration> conf = null;
+  protected SortedMap<byte [], V> instance = null;
   
   // Static maps of code to class and vice versa.  Includes types used in hbase
-  // only.
+  // only. These maps are now initialized in a static loader interface instead
-  static final Map<Byte, Class<?>> CODE_TO_CLASS =
+  // of in a static contructor for this class, this is done so that it is
-    new HashMap<Byte, Class<?>>();
+  // possible to have a regular contructor here, so that different params can
-  static final Map<Class<?>, Byte> CLASS_TO_CODE =
+  // be used.
-    new HashMap<Class<?>, Byte>();
+  
+  // Removed the old types like Text from the maps, if needed to add more types
+  // this can be done in the StaticHBaseMapWritableLoader interface. Only
+  // byte[] and Cell are supported now.
+  //   static final Map<Byte, Class<?>> CODE_TO_CLASS =
+  //     new HashMap<Byte, Class<?>>();
+  //   static final Map<Class<?>, Byte> CLASS_TO_CODE =
+  //     new HashMap<Class<?>, Byte>();
 
-  static {
+  /**
-    byte code = 0;
+   * The default contructor where a TreeMap is used
-    addToMap(HStoreKey.class, code++);
+   **/
-    addToMap(ImmutableBytesWritable.class, code++);
+   public HbaseMapWritable(){
-    addToMap(Text.class, code++);
+     this (new TreeMap<byte [], V>(Bytes.BYTES_COMPARATOR));
-    addToMap(Cell.class, code++);
+   }
-    addToMap(byte [].class, code++);
-  }
 
-  @SuppressWarnings("boxing")
+   /**
-  private static void addToMap(final Class<?> clazz,
+  * Contructor where another SortedMap can be used
-      final byte code) {
+  * 
-    CLASS_TO_CODE.put(clazz, code);
+  * @param map the SortedMap to be used 
-    CODE_TO_CLASS.put(code, clazz);
+  **/
+  public HbaseMapWritable(SortedMap<byte[], V> map){
+    conf = new AtomicReference<Configuration>();
+    instance = map;
   }
   
-  private SortedMap<byte [], V> instance =
+  
-    new TreeMap<byte [], V>(Bytes.BYTES_COMPARATOR);
-
   /** @return the conf */
   public Configuration getConf() {
     return conf.get();
@@ -228,4 +233,4 @@ implements SortedMap<byte [], V>, Writable, Configurable {
       this.instance.put(key, value);
     }
   }
-}
+}