TransportedVectorTime


1   // $Id: TransportedVectorTime.java,v 1.3 2004/12/01 10:17:50 belaban Exp $
2   
3   package org.jgroups.protocols;
4   
5   
6   import org.jgroups.Message;
7   
8   import java.io.Serializable  ;
9   
10  
11  
12  /**
13   * Lighweight representation of the VectorTime clock suitable for network transport
14   *
15   * @author Vladimir Blagojevic vladimir@cs.yorku.ca
16   * @version $Revision: 1.3 $
17   */
18  public class TransportedVectorTime implements Serializable  
19  {
20     /**
21      * index of the sender
22      */
23     int senderPosition;
24  
25     /**
26      * values represented as an array
27      */
28     int[] values;
29  
30     /**
31      * Message associated with this vector clock
32      */
33     private transient Message m;
34  
35     /**
36      *
37      */
38     public TransportedVectorTime()
39     {
40     }
41  
42     /**
43      * Constructs TransportedVectorTime with sender index and vector values
44      *
45      * @param senderIndex index of the sender of the message
46      * @param values vector values
47      */
48     public TransportedVectorTime(int senderIndex, int[] values)
49     {
50        this.values = values;
51        this.senderPosition = senderIndex;
52     }
53  
54     /**
55      * Returns sender index
56      * @return sender index position
57      */
58     public int getSenderIndex()
59     {
60        return senderPosition;
61     }
62  
63     /**
64      * Returns vector values
65      * @return an array of vector values
66      */
67     public int[] getValues()
68     {
69        return values;
70     }
71  
72     /**
73      * Returns size of this vector timestamp  i.e number of process group members
74      * @return vector timestamp size
75      */
76     public int size()
77     {
78        return values.length;
79     }
80  
81     /**
82      * Sets a message associated with this vector timestamp
83      * @param owner Message that is associated with this vector timestamp
84      */
85     public void setAssociatedMessage(Message owner)
86     {
87        m = owner;
88     }
89  
90     /**
91      *Returns a message associated with this vector timestamp
92      * @returnMessage associated with this vector timestamp
93      */
94     public Message getAssociatedMessage()
95     {
96        return m;
97     }
98  
99  
100    /**
101     *<p>
102     *Checks if this TransportedVectorTime is less than equal from the given
103     *other TransportedVectorTimeas follows:
104     *</p>
105     * <p>
106     * VT1<=VT2 iff for every i:1..k VT1[i]<=VT2[i]
107     * </p>
108     * @param other TransportedVectorTimebeing compared with this.
109     * @return true if this TransportedVectorTimeis less than or equal from
110     * other, false othwerwise
111     */
112    public boolean lessThanOrEqual(TransportedVectorTime other)
113    {
114       int[] b = other.getValues();
115       int[] a = values;
116       for (int k = 0; k < a.length; k++)
117       {
118 
119          if (a[k] <= b[k])
120             continue;
121          else
122             return false;
123       }
124       return true;
125    }
126 
127    /**
128     * <p>
129     * Checks if this TransportedVectorTimeis equal to given TransportedVectorTime
130     * as follows:
131     * </p>
132     * <p>
133     *  VT1==VT2 iff for every i:1..k VT1[i]==VT2[i]
134     * @param other TransportedVectorTimebeing compared with this.
135     * @return true if the above given equation is true, false otherwise
136     */
137    public boolean equals(TransportedVectorTime other)
138    {
139       int a [] = getValues();
140       int b [] = other.getValues();
141 
142       for (int i = 0; i < a.length; i++)
143          if (a[i] != b[i]) return false;
144 
145       return true;
146    }
147 
148    /**
149     * Returns String representation of this vector timestamp
150     * @return String representing this vetor timestamp
151     */
152    public String   toString()
153    {
154       String   classType = "TransportedVectorTime[";
155       int bufferLength = classType.length() + values.length * 2 + 1;
156       StringBuffer   buf = new StringBuffer  (bufferLength);
157       buf.append(classType);
158       for (int i = 0; i < values.length - 1; i++)
159       {
160          buf.append(values[i]).append(',');
161       }
162       buf.append(values[values.length - 1]);
163       buf.append(']');
164       return buf.toString();
165    }
166 }
167
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