com.diversityarrays.dalclient.util.Pair.java Source code

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

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/*
 * dalclient library - provides utilities to assist in using KDDart-DAL servers
 * Copyright (C) 2015,2016,2017 Diversity Arrays Technology
 * 
 * This program is free software: you can redistribute it and/or modify
 * it 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.
 * 
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package com.diversityarrays.dalclient.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.a + sep + p.b;
            }
        });
    }

    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 a;
    public final B b;
    private final String name;

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

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

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

        Pair<?, ?> other = (Pair<?, ?>) o;
        Object oa = other.a;
        Object ob = other.b;

        return (oa == null ? a == null : oa.equals(a)) && (ob == null ? b == null : ob.equals(b));
    }

    @Override
    public int hashCode() {
        return (a == null ? 0 : a.hashCode()) + (b == null ? 0 : b.hashCode());
    }

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

}