/*
    * 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.giraph.types;
  
  import org.apache.hadoop.io.Writable;
  
  import com.google.common.collect.Maps;
  
  import java.util.Map;
  
  import static org.apache.giraph.types.JavaWritablePair.BOOLEAN_BOOLEAN_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.BYTE_BYTE_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.BYTE_INT_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.BYTE_LONG_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.DOUBLE_DOUBLE_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.FLOAT_DOUBLE_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.FLOAT_FLOAT_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.INT_INT_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.INT_LONG_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.LONG_LONG_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.SHORT_INT_WRITABLE;
  import static org.apache.giraph.types.JavaWritablePair.SHORT_LONG_WRITABLE;
  
  /**
   * Mapping of all the known Writable wrappers.
   */
  public class WritableWrappers {
    /** Map of (Writable,Java)-type pair to wrapper for those types */
    private static final Map<JavaWritablePair, WritableWrapper> MAP;
  
    static {
      MAP = Maps.newHashMap();
      MAP.put(BOOLEAN_BOOLEAN_WRITABLE, new BooleanToBooleanWritableWrapper());
      MAP.put(BYTE_BYTE_WRITABLE, new ByteToByteWritableWrapper());
      MAP.put(BYTE_INT_WRITABLE, new ByteToIntWritableWrapper());
      MAP.put(BYTE_LONG_WRITABLE, new ByteToLongWritableWrapper());
      MAP.put(DOUBLE_DOUBLE_WRITABLE, new DoubleToDoubleWritableWrapper());
      MAP.put(FLOAT_DOUBLE_WRITABLE, new FloatToDoubleWritableWrapper());
      MAP.put(FLOAT_FLOAT_WRITABLE, new FloatToFloatWritableWrapper());
      MAP.put(INT_INT_WRITABLE, new IntToIntWritableWrapper());
      MAP.put(INT_LONG_WRITABLE, new IntToLongWritableWrapper());
      MAP.put(LONG_LONG_WRITABLE, new LongToLongWritableWrapper());
      MAP.put(SHORT_INT_WRITABLE, new ShortToIntWritableWrapper());
      MAP.put(SHORT_LONG_WRITABLE, new ShortToLongWritableWrapper());
    }
  
    /** Don't construct */
    private WritableWrappers() { }
  
    /**
     * Lookup type converter
     *
     * @param writableClass class of Writable
     * @param javaClass class of Java type
     * @param <W> Writable type
     * @param <J> Java type
     * @return {@link WritableWrapper}
     */
    public static <W extends Writable, J> WritableWrapper<W, J> lookup(
        Class<W> writableClass, Class<J> javaClass) {
      return lookup(JavaWritablePair.create(writableClass, javaClass));
    }
  
    /**
     * Lookup type converter
     *
     * @param classes JavaAndWritableClasses
     * @param <W> Writable type
     * @param <J> Java type
     * @return {@link WritableWrapper}
     */
    public static <W extends Writable, J> WritableWrapper<W, J> lookup(
        JavaWritablePair<W, J> classes) {
      return MAP.get(classes);
    }
  }