com.diversityarrays.util.Pair.java Source code

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Here is the source code for com.diversityarrays.util.Pair.java

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/*
KDXplore provides KDDart Data Exploration and Management
Copyright (C) 2015,2016,2017  Diversity Arrays Technology, Pty Ltd.
    
KDXplore may be redistributed and may be modified under the terms
of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option)
any later version.
    
KDXplore is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with KDXplore.  If not, see <http://www.gnu.org/licenses/>.
*/
package com.diversityarrays.util;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.commons.collections15.Transformer;

public class Pair<A, B> {

    static public <T> Pair<T, T>[] createHomogenousPairs(Collection<T> inputs, final String sep) {
        return createHomogenousPairs(inputs, new Transformer<Pair<T, T>, String>() {
            @Override
            public String transform(Pair<T, T> p) {
                return p.first + sep + p.second;
            }
        });
    }

    static public <T> Pair<T, T>[] createHomogenousPairs(Collection<T> inputs,
            Transformer<Pair<T, T>, String> joiner) {
        List<Pair<T, T>> result = new ArrayList<Pair<T, T>>();

        List<T> list = new ArrayList<T>(inputs);
        int n = list.size();
        if (n > 1) {
            for (int a = 0; a < n; ++a) {
                T aa = list.get(a);
                for (int b = a + 1; b < n; ++b) {
                    T bb = list.get(b);

                    Pair<T, T> pair = new Pair<T, T>(aa, bb, null);
                    String name = joiner.transform(pair);

                    result.add(new Pair<T, T>(aa, bb, name));

                    pair = new Pair<T, T>(bb, aa, null);
                    name = joiner.transform(pair);

                    result.add(new Pair<T, T>(bb, aa, name));
                }
            }
        }

        @SuppressWarnings("unchecked")
        Pair<T, T>[] pairs = (Pair<T, T>[]) Array.newInstance(Pair.class, result.size());
        pairs = result.toArray(pairs);

        return pairs;
    }

    public final A first;
    public final B second;
    private final String name;

    public Pair(A a, B b) {
        this(a, b, "(" + a + " , " + b + ")");
    }

    public Pair(A a, B b, String name) {
        this.first = a;
        this.second = b;
        this.name = name;
    }

    @Override
    public String toString() {
        return name;
    }

    @Override
    public int hashCode() {
        return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
    }

    @Override
    public boolean equals(Object o) {
        if (o == this)
            return true;
        if (!(o instanceof Pair))
            return false;

        Pair<?, ?> other = (Pair<?, ?>) o;
        Object oa = other.first;
        Object ob = other.second;

        return (oa == null ? first == null : oa.equals(first)) && (ob == null ? second == null : ob.equals(second));
    }

    public A getFirst() {
        return first;
    }

    public B getSecond() {
        return second;
    }
}