/*
* file: ArrayDemo.java
* package: oreilly.hcj.reflection
*
* 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.Array;
/**
* Demonstrates the use of the Array class.
*
* @author <a href=mailto:[email protected]>Robert Simmons jr. (kraythe)</a>
* @version $Revision$
*/
public class ArrayDemo {
/**
* Copy an array and return the copy.
*
* @param input The array to copy.
*
* @return The coppied array.
*
* @throws IllegalArgumentException If input is not an array.
*/
public static Object copyArray(final Object input) {
final Class type = input.getClass();
if (!type.isArray()) {
throw new IllegalArgumentException();
}
final int length = Array.getLength(input);
final Class componentType = type.getComponentType();
final Object result = Array.newInstance(componentType, length);
for (int idx = 0; idx < length; idx++) {
Array.set(result, idx, Array.get(input, idx));
}
return result;
}
/**
* Run the demo.
*
* @param args Command line arguments (ignored).
*/
public static void main(final String[] args) {
try {
int[] x = new int[] { 2, 3, 8, 7, 5 };
char[] y = new char[] { 'a', 'z', 'e' };
String[] z = new String[] { "Jim", "John", "Joe" };
System.out.println(" -- x and y --");
outputArrays(x, y);
System.out.println(" -- x and copy of x --");
outputArrays(x, copyArray(x));
System.out.println(" -- y and copy of y --");
outputArrays(y, copyArray(y));
System.out.println(" -- z and copy of z --");
outputArrays(z, copyArray(z));
} catch (final Exception ex) {
ex.printStackTrace();
}
}
/**
* Print out 2 arrays in columnar format.
*
* @param first The array for the first column.
* @param second The array for the second column.
*
* @throws IllegalArgumentException __UNDOCUMENTED__
*/
public static void outputArrays(final Object first, final Object second) {
if (!first.getClass()
.isArray()) {
throw new IllegalArgumentException("first is not an array.");
}
if (!second.getClass()
.isArray()) {
throw new IllegalArgumentException("second is not an array.");
}
final int lengthFirst = Array.getLength(first);
final int lengthSecond = Array.getLength(second);
final int length = Math.max(lengthFirst, lengthSecond);
for (int idx = 0; idx < length; idx++) {
System.out.print("[" + idx + "]\t");
if (idx < lengthFirst) {
System.out.print(Array.get(first, idx) + "\t\t");
} else {
System.out.print("\t\t");
}
if (idx < lengthSecond) {
System.out.print(Array.get(second, idx) + "\t");
}
System.out.println();
}
}
}
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