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/*
 * Copyright 2014 mango.jfaster.org
 *
 * The Mango Project 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.jfaster.mango.util;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * @author ash
 */
public final class Primitives {

  private Primitives() {
  }

  private static final Map, Class> PRIMITIVE_TO_WRAPPER_TYPE;

  private static final Map, Class> WRAPPER_TO_PRIMITIVE_TYPE;

  static {
    Map, Class> primToWrap = new HashMap, Class>(16);
    Map, Class> wrapToPrim = new HashMap, Class>(16);

    add(primToWrap, wrapToPrim, boolean.class, Boolean.class);
    add(primToWrap, wrapToPrim, byte.class, Byte.class);
    add(primToWrap, wrapToPrim, char.class, Character.class);
    add(primToWrap, wrapToPrim, double.class, Double.class);
    add(primToWrap, wrapToPrim, float.class, Float.class);
    add(primToWrap, wrapToPrim, int.class, Integer.class);
    add(primToWrap, wrapToPrim, long.class, Long.class);
    add(primToWrap, wrapToPrim, short.class, Short.class);

    PRIMITIVE_TO_WRAPPER_TYPE = Collections.unmodifiableMap(primToWrap);
    WRAPPER_TO_PRIMITIVE_TYPE = Collections.unmodifiableMap(wrapToPrim);
  }

  private static void add(Map, Class> forward,
                          Map, Class> backward, Class key, Class value) {
    forward.put(key, value);
    backward.put(value, key);
  }

  public static Set> allPrimitiveTypes() {
    return PRIMITIVE_TO_WRAPPER_TYPE.keySet();
  }

  public static Set> allWrapperTypes() {
    return WRAPPER_TO_PRIMITIVE_TYPE.keySet();
  }

  public static boolean isWrapperType(Class type) {
    return WRAPPER_TO_PRIMITIVE_TYPE.containsKey(type);
  }

  public static  Class wrap(Class type) {
    // cast is safe: long.class and Long.class are both of type Class
    @SuppressWarnings("unchecked")
    Class wrapped = (Class) PRIMITIVE_TO_WRAPPER_TYPE.get(type);
    return (wrapped == null) ? type : wrapped;
  }

  public static  Class unwrap(Class type) {
    // cast is safe: long.class and Long.class are both of type Class
    @SuppressWarnings("unchecked")
    Class unwrapped = (Class) WRAPPER_TO_PRIMITIVE_TYPE.get(type);
    return (unwrapped == null) ? type : unwrapped;
  }

}