functionconcatbytes.java

来自「High performance DB query」· Java 代码 · 共 70 行

/*
 * @(#)$Id: FunctionConcatbytes.java,v 1.1 2005/03/08 01:56:45 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;

/**
 * Class FunctionConcat
 *
 */
public class FunctionConcatbytes implements Function {

    /**
     * Method evaluate
     *
     * @param parameters
     * @return
     */
    public Object evaluate(Object[] parameters) {
        int params = parameters.length;
        int newlength = 0;

        for (int i = 0; i < params; i++) {
            if (parameters[i] instanceof Byte[]) {
                newlength += ((Byte[]) parameters[i]).length;
            }
        }

        Byte[] resultArr = new Byte[newlength];
        int offset = 0;

        for (int i = 0; i < params; i++) {
            if (parameters[i] instanceof Byte[]) {
                int sourceLength = ((Byte[]) parameters[i]).length;

                System.arraycopy(parameters[i], 0, resultArr, offset,
                                 sourceLength);

                offset += sourceLength;
            }
        }

        return resultArr;
    }

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