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 * published by the Free Software Foundation.  Oracle designates this

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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

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package com.sun.tools.internal.xjc.model;

import java.math.BigInteger;

/**

 * represents a possible number of occurence.

 *

 * Usually, denoted by a pair of integers like (1,1) or (5,10).

 * A special value "unbounded" is allowed as the upper bound.

 *

 * <p>

 * For example, (0,unbounded) corresponds to the '*' occurence of DTD.

 * (0,1) corresponds to the '?' occurence of DTD.

 *

 * @author

 *    <a href="mailto:kohsuke.kawaguchi@sun.com">Kohsuke KAWAGUCHI</a>

 */

public final class Multiplicity {

    public final BigInteger min;

    public final BigInteger max;    // null is used to represent "unbounded".

    public static Multiplicity create(BigInteger min, BigInteger max ) {

        if (BigInteger.ZERO.equals(min) && max==null) return STAR;

        if (BigInteger.ONE.equals(min) && max==null) return PLUS;

        if (max!=null) {

            if(BigInteger.ZERO.equals(min) && BigInteger.ZERO.equals(max))    return ZERO;

            if(BigInteger.ZERO.equals(min) && BigInteger.ONE.equals(max))    return OPTIONAL;

            if(BigInteger.ONE.equals(min) && BigInteger.ONE.equals(max))    return ONE;

        }

        return new Multiplicity(min, max);

    }

    public static Multiplicity create(int min, Integer max ) {

        return Multiplicity.create(BigInteger.valueOf(min), BigInteger.valueOf(max.intValue()));

    }

    private Multiplicity(BigInteger min, BigInteger max) {

        this.min = min;

        this.max = max;

    }

    private Multiplicity(int min, int max) {

        this(BigInteger.valueOf(min), BigInteger.valueOf(max));

    }

    private Multiplicity(int min, Integer max) {

        this(BigInteger.valueOf(min), (max == null) ? null : BigInteger.valueOf(max));

    }

    @Override

    public boolean equals(Object o) {

        if (!(o instanceof Multiplicity)) return false;

        Multiplicity that = (Multiplicity) o;

        if (!this.min.equals(that.min)) return false;

        if (this.max != null ? !this.max.equals(that.max) : that.max != null) return false;

        return true;

    }

    @Override

    public int hashCode() {

        return min.add(max).intValue();

    }

    /** returns true if the multiplicity is (1,1). */

    public boolean isUnique() {

        if(max==null)    return false;

        return BigInteger.ONE.equals(min) && BigInteger.ONE.equals(max);

    }

    /** returns true if the multiplicity is (0,1) */

    public boolean isOptional() {

        if(max==null) return false;

        return BigInteger.ZERO.equals(min) && BigInteger.ONE.equals(max);

    }

    /** returns true if the multiplicity is (0,1) or (1,1). */

    public boolean isAtMostOnce() {

        if(max==null)    return false;

        return max.compareTo(BigInteger.ONE)<=0;

    }

    /** returns true if the multiplicity is (0,0). */

    public boolean isZero() {

        if(max==null)    return false;

        return BigInteger.ZERO.equals(max);

    }

    /**

     * Returns true if the multiplicity represented by this object

     * completely includes the multiplicity represented by the

     * other object. For example, we say [1,3] includes [1,2] but

     * [2,4] doesn't include [1,3].

     */

    public boolean includes( Multiplicity rhs ) {

        if (rhs.min.compareTo(min) == -1)   return false;

        if (max==null) return true;

        if (rhs.max==null) return false;

        return rhs.max.compareTo(max) <= 0;

    }

    /**

     * Returns the string representation of the 'max' property.

     * Either a number or a token "unbounded".

     */

    public String getMaxString() {

        if(max==null)       return "unbounded";

        else                return max.toString();

    }

    /** gets the string representation.

     * mainly debug purpose.

     */

    @Override

    public String toString() {

        return "("+min+','+getMaxString()+')';

    }

    /** the constant representing the (0,0) multiplicity. */

    public static final Multiplicity ZERO = new Multiplicity(0,0);

    /** the constant representing the (1,1) multiplicity. */

    public static final Multiplicity ONE = new Multiplicity(1,1);

    /** the constant representing the (0,1) multiplicity. */

    public static final Multiplicity OPTIONAL = new Multiplicity(0,1);

    /** the constant representing the (0,unbounded) multiplicity. */

    public static final Multiplicity STAR = new Multiplicity(0,null);

    /** the constant representing the (1,unbounded) multiplicity. */

    public static final Multiplicity PLUS = new Multiplicity(1,null);

// arithmetic methods

    public static Multiplicity choice( Multiplicity lhs, Multiplicity rhs ) {

        return create(

            lhs.min.min(rhs.min),

            (lhs.max==null || rhs.max==null) ? null : lhs.max.max(rhs.max) );

    }

    public static Multiplicity group( Multiplicity lhs, Multiplicity rhs ) {

        return create(

            lhs.min.add(rhs.min),

            (lhs.max==null || rhs.max==null) ? null : lhs.max.add(rhs.max) );

    }

    public static Multiplicity multiply( Multiplicity lhs, Multiplicity rhs ) {

        BigInteger min = lhs.min.multiply(rhs.min);

        BigInteger max;

        if (isZero(lhs.max) || isZero(rhs.max))

            max = BigInteger.ZERO;

        else

        if (lhs.max==null || rhs.max==null)

            max = null;

        else

            max = lhs.max.multiply(rhs.max);

        return create(min,max);

    }

    private static boolean isZero(BigInteger i) {

        return (i != null && BigInteger.ZERO.equals(i));

    }

    public static Multiplicity oneOrMore( Multiplicity c ) {

        if(c.max==null)  return c; // (x,*) => (x,*)

        if(BigInteger.ZERO.equals(c.max)) return c; // (0,0) => (0,0)

        else        return create( c.min, null );    // (x,y) => (x,*)

    }

    public Multiplicity makeOptional() {

        if (BigInteger.ZERO.equals(min)) return this;

        return create(BigInteger.ZERO, max);

    }

    public Multiplicity makeRepeated() {

        if (max==null || BigInteger.ZERO.equals(max))  return this;   // (0,0)* = (0,0)  and (n,unbounded)* = (n,unbounded)

        return create(min,null);

    }

}