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/*
 * DomUI Java User Interface - shared code
 * Copyright (c) 2010 by Frits Jalvingh, Itris B.V.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * See the "sponsors" file for a list of supporters.
 *
 * The latest version of DomUI and related code, support and documentation
 * can be found at http://www.domui.org/
 * The contact for the project is Frits Jalvingh .
 */
package javax.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

import javax.annotation.meta.TypeQualifier;
import javax.annotation.meta.TypeQualifierValidator;
import javax.annotation.meta.When;

/** Used to annotate a value that should only contain nonnegative values */
@Documented
@TypeQualifier(applicableTo = Number.class)
@Retention(RetentionPolicy.RUNTIME)
public @interface Nonnegative {
    When when() default When.ALWAYS;

    class Checker implements TypeQualifierValidator {

        public When forConstantValue(Nonnegative annotation, Object v) {
            if (!(v instanceof Number))
                return When.NEVER;
            boolean isNegative;
            Number value = (Number) v;
            if (value instanceof Long)
                isNegative = value.longValue() < 0;
            else if (value instanceof Double)
                isNegative = value.doubleValue() < 0;
            else if (value instanceof Float)
                isNegative = value.floatValue() < 0;
            else
                isNegative = value.intValue() < 0;

            if (isNegative)
                return When.NEVER;
            else
                return When.ALWAYS;

        }
    }
}