/*
    * 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.myfaces.tobago.util;
  
  import java.text.CollationKey;
  import java.text.Collator;
  import java.util.Comparator;
  
  
  public abstract class ComparatorBase implements Comparator {
  
    private Comparator comparator;
  
    private boolean reverse;
  
    protected ComparatorBase() {
    }
  
    protected ComparatorBase(final boolean reverse, final Comparator comparator) {
      this.comparator = comparator;
      this.reverse = reverse;
    }
  
    protected ComparatorBase(final boolean reverse) {
      this.reverse = reverse;
    }
  
    protected ComparatorBase(final Comparator comparator) {
      this.comparator = comparator;
    }
  
    protected int internalCompare(final Object obj1, final Object obj2) {
  
      final int result;
      if (obj1 == null || obj2 == null) {
        if (obj1 == null && obj2 == null) {
          result = 0;
        } else {
          if (obj1 == null) {
            result = 1;
          } else {
            result = -1;
          }
        }
      } else if (!obj1.getClass().isInstance(obj2)) {
        throw new ClassCastException(obj1.getClass().getName() + " != " + obj2.getClass().getName());
      } else {
        if (comparator instanceof Collator) {
          final CollationKey collationKey1
              = ((Collator) comparator).getCollationKey(obj1.toString());
          final CollationKey collationKey2
              = ((Collator) comparator).getCollationKey(obj2.toString());
          result = collationKey1.compareTo(collationKey2);
        } else if (comparator != null) {
          result = comparator.compare(obj1, obj2);
        } else {
          if (obj1 instanceof String) {
            result = ((String) obj1).compareToIgnoreCase((String) obj2);
          } else if (obj1 instanceof Comparable) {
            result = ((Comparable) obj1).compareTo(obj2);
          } else {
            result = obj1.toString().compareTo(obj2.toString());
          }
        }
      }
      return reverse ? -result : result;
    }
  
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
  
      final ComparatorBase that = (ComparatorBase) o;
  
      return comparator != null ? comparator.equals(that.comparator) : that.comparator == null;
  
    }
  
   public int hashCode() {
     return comparator != null ? comparator.hashCode() : 0;
   }
 
   public Comparator getComparator() {
     return comparator;
   }
 }