1 /*
   2  * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package jdk.vm.ci.meta;
  24 
  25 /**
  26  * A profiled type that has a probability. Profiled types are naturally sorted in descending order
  27  * of their probabilities.
  28  */
  29 public abstract class AbstractProfiledItem<T> implements Comparable<AbstractProfiledItem<?>> {
  30 
  31     protected final T item;
  32     protected final double probability;
  33 
  34     public AbstractProfiledItem(T item, double probability) {
  35         assert item != null;
  36         assert probability >= 0.0D && probability <= 1.0D;
  37         this.item = item;
  38         this.probability = probability;
  39     }
  40 
  41     protected T getItem() {
  42         return item;
  43     }
  44 
  45     /**
  46      * Returns the estimated probability of {@link #getItem()}.
  47      *
  48      * @return double value &ge; 0.0 and &le; 1.0
  49      */
  50     public double getProbability() {
  51         return probability;
  52     }
  53 
  54     @Override
  55     public int compareTo(AbstractProfiledItem<?> o) {
  56         if (getProbability() > o.getProbability()) {
  57             return -1;
  58         } else if (getProbability() < o.getProbability()) {
  59             return 1;
  60         }
  61         return 0;
  62     }
  63 
  64     @Override
  65     public int hashCode() {
  66         final int prime = 31;
  67         int result = 1;
  68         long temp;
  69         temp = Double.doubleToLongBits(probability);
  70         result = prime * result + (int) (temp ^ (temp >>> 32));
  71         result = prime * result + item.hashCode();
  72         return result;
  73     }
  74 
  75     @Override
  76     public boolean equals(Object obj) {
  77         if (this == obj) {
  78             return true;
  79         }
  80         if (obj == null) {
  81             return false;
  82         }
  83         if (getClass() != obj.getClass()) {
  84             return false;
  85         }
  86         AbstractProfiledItem<?> other = (AbstractProfiledItem<?>) obj;
  87         if (Double.doubleToLongBits(probability) != Double.doubleToLongBits(other.probability)) {
  88             return false;
  89         }
  90         return item.equals(other.item);
  91     }
  92 
  93     @Override
  94     public abstract String toString();
  95 }