edu.stanford.nlp.util.IntTuple.java Source code

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Here is the source code for edu.stanford.nlp.util.IntTuple.java

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package edu.stanford.nlp.util;

import java.io.Serializable;
import java.util.List;

/**
 * A tuple of int. There are special classes for IntUni, IntPair, IntTriple
 * and IntQuadruple. The motivation for that was the different hashCode
 * implementations.
 * By using the static IntTuple.getIntTuple(numElements) one can obtain an
 * instance of the appropriate sub-class.
 *
 * @author Kristina Toutanova (kristina@cs.stanford.edu)
 */
public class IntTuple implements Serializable, Comparable<IntTuple> {

    final int[] elements;

    private static final long serialVersionUID = 7266305463893511982L;

    public IntTuple(int[] arr) {
        elements = arr;
    }

    public IntTuple(int num) {
        elements = new int[num];
    }

    @Override
    public int compareTo(IntTuple o) {
        int commonLen = Math.min(o.length(), length());
        for (int i = 0; i < commonLen; i++) {
            int a = get(i);
            int b = o.get(i);
            if (a < b)
                return -1;
            if (b < a)
                return 1;
        }
        if (o.length() == length()) {
            return 0;
        } else {
            return (length() < o.length()) ? -1 : 1;
        }
    }

    public int get(int num) {
        return elements[num];
    }

    public void set(int num, int val) {
        elements[num] = val;
    }

    public void shiftLeft() {
        System.arraycopy(elements, 1, elements, 0, elements.length - 1); // the API does guarantee that this works when src and dest overlap, as here
        elements[elements.length - 1] = 0;
    }

    public IntTuple getCopy() {
        IntTuple copy = IntTuple.getIntTuple(elements.length); //new IntTuple(numElements);
        System.arraycopy(elements, 0, copy.elements, 0, elements.length);
        return copy;
    }

    public int[] elems() {
        return elements;
    }

    @Override
    public boolean equals(Object iO) {
        if (!(iO instanceof IntTuple)) {
            return false;
        }
        IntTuple i = (IntTuple) iO;
        if (i.elements.length != elements.length) {
            return false;
        }
        for (int j = 0; j < elements.length; j++) {
            if (elements[j] != i.get(j)) {
                return false;
            }
        }
        return true;
    }

    @Override
    public int hashCode() {
        int sum = 0;
        for (int element : elements) {
            sum = sum * 17 + element;
        }
        return sum;
    }

    public int length() {
        return elements.length;
    }

    public static IntTuple getIntTuple(int num) {
        if (num == 1) {
            return new IntUni();
        }
        if ((num == 2)) {
            return new IntPair();
        }
        if (num == 3) {
            return new IntTriple();
        }
        if (num == 4) {
            return new IntQuadruple();
        } else {
            return new IntTuple(num);
        }
    }

    public static IntTuple getIntTuple(List<Integer> integers) {
        IntTuple t = IntTuple.getIntTuple(integers.size());
        for (int i = 0; i < t.length(); i++) {
            t.set(i, integers.get(i).intValue());
        }
        return t;
    }

    @Override
    public String toString() {
        StringBuilder name = new StringBuilder();
        for (int i = 0; i < elements.length; i++) {
            name.append(get(i));
            if (i < elements.length - 1) {
                name.append(' ');
            }
        }
        return name.toString();
    }

    public static IntTuple concat(IntTuple t1, IntTuple t2) {
        int n1 = t1.length();
        int n2 = t2.length();
        IntTuple res = IntTuple.getIntTuple(n1 + n2);

        for (int j = 0; j < n1; j++) {
            res.set(j, t1.get(j));
        }
        for (int i = 0; i < n2; i++) {
            res.set(n1 + i, t2.get(i));
        }
        return res;
    }

    public void print() {
        String s = toString();
        System.out.print(s);
    }

}