FieldModification.java Source code

Introduction

Here is the source code for FieldModification.java

Source

/*
Before: [a=21.25, b=54.5, c=5665, d=2043, e=3121, f=1019]
After: [a=21.25, b=54.5, c=0, d=0, e=3121, f=1019]
*/

/*
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
########## DO NOT EDIT ABOVE THIS LINE ########## */

import java.lang.reflect.Field;

/**  
 * Demonstrates how to set public field objects.
 *
 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
 * @version $Revision: 1.3 $
 */
public class FieldModification {
    /** 
     * Sets all int fields in an object to 0.
     *
     * @param obj The object to operate on.
     *
     * @throws RuntimeException If there is a reflection problem.
     */
    public static void initPublicIntFields(final Object obj) {
        try {
            Field[] fields = obj.getClass().getFields();
            for (int idx = 0; idx < fields.length; idx++) {
                if (fields[idx].getType() == int.class) {
                    fields[idx].setInt(obj, 0);
                }
            }
        } catch (final IllegalAccessException ex) {
            throw new RuntimeException(ex);
        }
    }

    /** 
     * Sets all int fields in an object to 0.
     *
     * @param obj The object to operate on.
     *
     * @throws RuntimeException If there is a reflection problem.
     */
    public static void initPublicIntFields2(final Object obj) {
        try {
            final Integer value = new Integer(0);
            Field[] fields = obj.getClass().getFields();
            for (int idx = 0; idx < fields.length; idx++) {
                if (fields[idx].getType() == int.class) {
                    fields[idx].set(obj, value);
                }
            }
        } catch (final IllegalAccessException ex) {
            throw new RuntimeException(ex);
        }
    }

    /** 
     * Demo Method.
     *
     * @param args Command line arguments.
     */
    public static final void main(final String[] args) {
        SomeNumbers value = new SomeNumbers();
        System.out.println("Before: " + value);
        initPublicIntFields(value);
        System.out.println("After: " + value);
    }
}

class SomeNumbers {
    /** A demo double. */
    public double a = 21.25d;

    /** A demo float. */
    public float b = 54.5f;

    /** A Demo int */
    public int c = 5665;

    /** Another demo int. */
    public int d = 2043;

    /** Another demo int. */
    protected int e = 3121;

    /** Another demo int. */
    private int f = 1019;

    /** 
     * @see java.lang.Object#toString()
     */
    public String toString() {
        return new String("[a=" + a + ", b=" + b + ", c=" + c + ", d=" + d + ", e=" + e + ", f=" + f + "]");
    }
}