001/*
002 * $Id: WordPair.java 5687 2017-01-03 08:44:03Z kredel $
003 */
004
005package edu.jas.gb;
006
007
008import edu.jas.poly.GenWordPolynomial;
009import edu.jas.structure.RingElem;
010
011
012/**
013 * Serializable subclass to hold pairs of word polynomials.
014 * @param <C> coefficient type
015 * @author Heinz Kredel
016 */
017public class WordPair<C extends RingElem<C>> implements Comparable<WordPair> {
018
019
020    public final GenWordPolynomial<C> pi;
021
022
023    public final GenWordPolynomial<C> pj;
024
025
026    public final int i;
027
028
029    public final int j;
030
031
032    protected int n;
033
034
035    /**
036     * WordPair constructor.
037     * @param a word polynomial i.
038     * @param b word polynomial j.
039     * @param i first index.
040     * @param j second index.
041     */
042    public WordPair(GenWordPolynomial<C> a, GenWordPolynomial<C> b, int i, int j) {
043        pi = a;
044        pj = b;
045        this.i = i;
046        this.j = j;
047        this.n = 0;
048    }
049
050
051    /**
052     * toString.
053     */
054    @Override
055    public String toString() {
056        return "wordPair(" + i + "," + j + ",{" + pi.length() + "," + pj.length() + "}," + n + ")";
057    }
058
059
060    /**
061     * Set removed pair number.
062     * @param n number of this pair generated in OrderedPairlist.
063     */
064    public void pairNumber(int n) {
065        this.n = n;
066    }
067
068
069    /**
070     * Get removed pair number.
071     * @return n number of this pair generated in OrderedPairlist.
072     */
073    public int getPairNumber() {
074        return n;
075    }
076
077
078    /**
079     * equals.
080     * @param ob an Object.
081     * @return true if this is equal to o, else false.
082     */
083    @Override
084    public boolean equals(Object ob) {
085        if (!(ob instanceof WordPair)) {
086            return false;
087            // throw new ClassCastException("Pair "+n+" o "+o);
088        }
089        return 0 == compareTo((WordPair) ob);
090    }
091
092
093    /**
094     * compareTo used in TreeMap // not used at moment. Comparison is based on
095     * the number of the pairs.
096     * @param p a WordPair.
097     * @return 1 if (this &lt; o), 0 if (this == o), -1 if (this &gt; o).
098     */
099    public int compareTo(WordPair p) {
100        int x = p.getPairNumber();
101        if (n > x) {
102            return 1;
103        }
104        if (n < x) {
105            return -1;
106        }
107        return 0;
108    }
109
110
111    /**
112     * Hash code for this WordPair.
113     * @see java.lang.Object#hashCode()
114     */
115    @Override
116    public int hashCode() {
117        return (i << 16) + j;
118    }
119
120}