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// : appendixa:Immutable1.java
// Objects that cannot be modified are immune to aliasing.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
public class Immutable1 {
private int data;
public Immutable1(int initVal) {
data = initVal;
}
public int read() {
return data;
}
public boolean nonzero() {
return data != 0;
}
public Immutable1 multiply(int multiplier) {
return new Immutable1(data * multiplier);
}
public static void f(Immutable1 i1) {
Immutable1 quad = i1.multiply(4);
System.out.println("i1 = " + i1.read());
System.out.println("quad = " + quad.read());
}
public static void main(String[] args) {
Immutable1 x = new Immutable1(47);
System.out.println("x = " + x.read());
f(x);
System.out.println("x = " + x.read());
}
} ///:~
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