org.eclipse.linuxtools.lttng.core/src/org/eclipse/linuxtools/internal/lttng/core/util/Pair.java

   1 /*******************************************************************************
   2  * Copyright (c) 2011 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Philippe Sawicki (INF4990.A2010@gmail.com)   - Initial API and implementation
  11  *   Mathieu Denis    (mathieu.denis55@gmail.com) - Refactored code
  12  *******************************************************************************/
  13 package org.eclipse.linuxtools.internal.lttng.core.util;
  14
  15 /**
  16  * Pair utility class, encapsulates a pair of objects.
  17  *
  18  * @author Philippe Sawicki
  19  *
  20  * @param <A>
  21  *            The type of the first object.
  22  * @param <B>
  23  *            The type of the second object.
  24  */
  25 public abstract class Pair<A, B> {
  26
  27     /**
  28      * A reference to the first object.
  29      */
  30     protected A fFirst;
  31     /**
  32      * A reference to the second object.
  33      */
  34     protected B fSecond;
  35
  36     /**
  37      * Constructor.
  38      * @param first
  39      *            The pair's first object.
  40      * @param second
  41      *            The pair's second object.
  42      */
  43     public Pair(A first, B second) {
  44         fFirst = first;
  45         fSecond = second;
  46     }
  47
  48     /**
  49      * Constructor.
  50      */
  51     public Pair() {
  52         this(null, null);
  53     }
  54
  55     /**
  56      * Pair hash code.
  57      */
  58     @Override
  59     public int hashCode() {
  60         int hashFirst = fFirst != null ? fFirst.hashCode() : 0;
  61         int hashSecond = fSecond != null ? fSecond.hashCode() : 0;
  62
  63         return (hashFirst + hashSecond) * hashSecond + hashFirst;
  64     }
  65
  66     /**
  67      * Object comparison.
  68      */
  69     @Override
  70     @SuppressWarnings("unchecked")
  71     public boolean equals(Object other) {
  72         if (other instanceof Pair) {
  73             Pair<A, B> otherPair = (Pair<A, B>) other;
  74             return ((fFirst == otherPair.fFirst || (fFirst != null && otherPair.fFirst != null && fFirst.equals(otherPair.fFirst))) && (fSecond == otherPair.fSecond || (fSecond != null
  75                     && otherPair.fSecond != null && fSecond.equals(otherPair.fSecond))));
  76         }
  77         return false;
  78     }
  79
  80     /**
  81      * Object to string.
  82      */
  83     @Override
  84     public String toString() {
  85         return "(" + fFirst + ", " + fSecond + ")";  //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
  86     }
  87
  88     /**
  89      * Returns a reference to the pair's first object.
  90      * @return A reference to the pair's first object.
  91      */
  92     public A getFirst() {
  93         return fFirst;
  94     }
  95
  96     /**
  97      * Sets the pair's first object.
  98      * @param first
  99      *            The pair's first object.
 100      */
 101     public void setFirst(A first) {
 102         fFirst = first;
 103     }
 104
 105     /**
 106      * Returns a reference to the pair's second object.
 107      * @return A reference to the pair's second object.
 108      */
 109     public B getSecond() {
 110         return fSecond;
 111     }
 112
 113     /**
 114      * Sets the pair's second object.
 115      * @param second
 116      *            The pair's second object.
 117      */
 118     public void setSecond(B second) {
 119         fSecond = second;
 120     }
 121 }