Symantec Visual Cafe for Java 2.5/symantec-visual-cafe-2.5-database-dev-edition.iso/VCafe/prosrc.bin/MatrixEnumeration.java

Java Source | 1998-03-18 | 5.3 KB | 187 lines

/*
 * Copyright (c) 1996 Krumel & Associates, Inc. All Rights Reserved.
 *
 * www.krumel.com - [e-mail]
 *
 * Permission is given to the buyer of this package for one software
 * developer to use this software on one CPU (one workstation) and to make
 * one backup copy.  You may uitilize and/or midfy this class for use in your
 * projects.  You may distribute or sell any executable which results from
 * using this code in yur application, except a utility or class of similar
 * nature to this product.  You may distribute this this product in compiled
 * form only, but soley to be used with your cmpiled executable product
 * for the puposes of dynamic loading. You may NOT redistribute the source
 * code in any form or make it accessible through a network or other
 * distribution media to others. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * The source code is the confidential and proprietary information
 * of Krumel & Associates, Inc. ("Confidential Information").  You shall
 * not disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Krumel & Associates, Inc..

 * KRUMEL & ASSOCIATES MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE
 * SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. KRUMEL & ASSOCIATES SHALL NOT
 * BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING,
 * MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

package symantec.itools.db.awt.genutil;

import java.util.Enumeration;

/**
 * An enumeration for the Matrix class.
 *
 * @version 1.1   June 2, 1997
 * @author  Andy Krumel
 */
public class MatrixEnumeration implements Enumeration {
    Matrix m ;
    int row = -1;
    MatrixElement elt;

    /**
     * Creates an enumeration for a matrix.
     */
    public MatrixEnumeration(Matrix matrix) {
        m = (Matrix)matrix.clone();
    }

    /**
     * Determines if more data exists in matrix.
     */
    public final boolean hasMoreElements() {
        if (m==null) {
            //already iterated
            return false;
        } else if (row==-1) {
            //have not gotten first element so see if any in matrix
            int size = m.rows();
            int currRow = 0;
            while(!m.containsRow(currRow)) {
                currRow++;
                if (size<currRow) { return false; }
            }

            return true;
        }

        return elt!=null;
    }

    /**
     * Determines if more valid rows exist in the matrix.
     */
    public final boolean hasMoreRows() {
        int size = m.rows();
        int nextRow = row+1;

        while(!m.containsRow(nextRow)) {
            nextRow++;
            if (size < nextRow) {
                return false;
            }
        }

        return true;
    }

    /**
     * Gets the next object.
     */
    public final Object nextElement() {
        if (row==-1 || elt.next==null) {
            findNextRow();
        } else {
            elt = elt.next;
        }

        return elt.obj;
    }

    private MatrixElement findNextRow() {
        int size = m.rows();
        row++;
        while(!m.containsRow(row)) {
            row++;
            if (size<row) {
                //no data left in matrix so we are done
                m = null;
                return null;
            }
        }

        return elt = m.firstRowElement(row);
    }

    /**
     * Gets the row number for the current element.
     */
    public final int currRow() { return row; }

    /**
     * Gets the column number for the current element.
     */
    public final int currCol() {
        if (elt==null) {
            return -1;
        } else {
            return elt.col;
        }
    }

    /**
     * Moves the matrix element pointer to the next valid row and returns the
     * first element in that row.
     */
    public final Object nextRow() {
        findNextRow();

        if (elt==null) {
            return null;
        }

        return elt.obj;
    }

    /**
     * Moves the matrix element pointer to the specified row. If no data exists
     * for that row, the pointer is moved to the next row with data.
     * @return The first object at that row (or next valid row) or null if no more
     *      valid rows exist.
     */
    public final Object advanceTo(int r) throws IllegalArgumentException {
        if (r < row || r == row)
            throw new
               IllegalArgumentException("r must be greater than current row: r=" +
                                         r + " current row=" + row);

        if (r > m.rows()) {
            throw new IllegalArgumentException("requested row too large: r=" + r);
        }

        int size = m.rows();
        row = r;
        while(!m.containsRow(row)) {
            row++;
            if (size < row) {
                //no data left in matrix we are done
                m = null;
                return null;
            }
        }

        elt = m.firstRowElement(row);

        return elt.obj;
    }

    public final String toString() {
        return "MatrixEnumeration: row="+row+" col="+ (elt!=null ?(""+elt.col) :"-");
    }
}