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package Torello.Java.Additional;

import java.lang.reflect.Field;

/**
 * This simple generic-class allows for storing <B STYLE='color:red'>two</B> objects with a 
 * single reference.
 *
 * <EMBED CLASS=globalDefs DATA-KIND=Tuple DATA-N=2>
 * <EMBED CLASS='external-html' DATA-FILE-ID=MUTABLE_TUPLE>
 * @param <A> The type of the <B STYLE='color:red'>first</B> member-field ('{@link #a}').
 * @param <B> The type of the <B STYLE='color:red'>second</B> member-field ('{@link #b}').
 */
public class Tuple2<A, B>
    extends TupleN
    implements java.io.Serializable, Cloneable
{
    /** <EMBED CLASS='external-html' DATA-FILE-ID=SVUID>  */
    protected static final long serialVersionUID = 1;

    /** This holds a pointer the first field / instance. */
    public A a;

    /** This holds a pointer to the second field / instance. */
    public B b;

    /** Constructs this object */
    public Tuple2(A a, B b)
    {
        this.a = a;
        this.b = b;
    }

    /** Constructs this object. Initializes both fields to null. */
    public Tuple2()
    {
        this.a = null;
        this.b = null;
    }

    /**
     * Returns {@code '2'}, indicating how many fields are declared by this class.
     * @return As an instance of {@code Tuple1}, this method returns {@code '2'};
     */
    public int n() { return 2; }

    // Super-class uses this for toString, equals, and hashCode
    // There is an optimization, so if this is requested multiple times, it is saved in a
    // transient field.

    final Object[] asArrayInternal()
    { return new Object[] { a, b }; }

    public Tuple2<A, B> clone()
    { return new Tuple2<>(this.a, this.b); }

    /**
     * <EMBED CLASS=defs DATA-TEXT="Integer">
     * <EMBED CLASS='external-html' DATA-FILE-ID=MULTI_TYPE_EX_COMMON>
     * <EMBED CLASS='external-html' DATA-FILE-ID=MULTI_TYPE_GET_EXAMPLE>
     */
    public Object get(final int i)
    {
        // Throws Exception if i not 1 or 2
        CHECK_GET(i);
        return (i == 1) ? a : b;
    }

    public Ret2<A, B> toImmutable()
    { return new Ret2<>(this.a, this.b); }
}