functionrandom.java

来自「High performance DB query」· Java 代码 · 共 94 行

/*
 * @(#)$Id: FunctionRandom.java,v 1.5 2004/07/02 23:59:21 huebsch Exp $
 *
 * Copyright (c) 2001-2004 Regents of the University of California.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached BERKELEY-LICENSE
 * file. If you do not find these files, copies can be found by writing to:
 * Computer Science Division, Database Group, Universite of California,
 * 617 Soda Hall #1776, Berkeley, CA 94720-1776. Attention: Berkeley License
 *
 * Copyright (c) 2003-2004 Intel Corporation. All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE file.
 * If you do not find these files, copies can be found by writing to:
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300,
 * Berkeley, CA, 94704.  Attention:  Intel License Inquiry.
 */


package pier.helpers.functions;

import services.LocalNode;

/**
 * Class FunctionRandom
 *
 */
public class FunctionRandom implements Function {

    public static final String RANDOM_BOOLEAN = "BOOLEAN";
    public static final String RANDOM_DOUBLE = "DOUBLE";
    public static final String RANDOM_FLOAT = "FLOAT";
    public static final String RANDOM_GAUSSIAN = "GAUSSIAN";
    public static final String RANDOM_INT = "INT";
    public static final String RANDOM_LONG = "LONG";

    /**
     * Method evaluate
     *
     * @param parameters
     * @return
     */
    public Object evaluate(Object[] parameters) {
        int params = parameters.length;

        if (params == 0) {
            return new Integer(LocalNode.myRandom.nextInt());
        }

        String type = parameters[0].toString();

        if (type.equalsIgnoreCase(RANDOM_INT)) {
            if (params == 2) {
                return new Integer(
                    LocalNode.myRandom.nextInt(
                        ((Integer) parameters[1]).intValue()));
            } else {
                return new Integer(LocalNode.myRandom.nextInt());
            }
        }

        if (type.equalsIgnoreCase(RANDOM_BOOLEAN)) {
            return new Boolean(LocalNode.myRandom.nextBoolean());
        }

        if (type.equalsIgnoreCase(RANDOM_DOUBLE)) {
            return new Double(LocalNode.myRandom.nextDouble());
        }

        if (type.equalsIgnoreCase(RANDOM_FLOAT)) {
            return new Float(LocalNode.myRandom.nextFloat());
        }

        if (type.equalsIgnoreCase(RANDOM_GAUSSIAN)) {
            return new Double(LocalNode.myRandom.nextGaussian());
        }

        if (type.equalsIgnoreCase(RANDOM_LONG)) {
            return new Long(LocalNode.myRandom.nextLong());
        }

        return null;
    }

    /**
     * Method cacheable
     * @return
     */
    public boolean cacheable() {
        return false;
    }
}