package net.jcip.examples;

import java.util.concurrent.atomic.*;

/**

* NumberRange

* <p/>

* Number range class that does not sufficiently protect its invariants

*

* @author Brian Goetz and Tim Peierls

*/

public class NumberRange {

// INVARIANT: lower <= upper

private final AtomicInteger lower = new AtomicInteger(0);

private final AtomicInteger upper = new AtomicInteger(0);

public void setLower(int i) {

// Warning -- unsafe check-then-act

if (i > upper.get())

throw new IllegalArgumentException("can't set lower to " + i + " > upper");

lower.set(i);

}

public void setUpper(int i) {

// Warning -- unsafe check-then-act

if (i < lower.get())

throw new IllegalArgumentException("can't set upper to " + i + " < lower");

upper.set(i);

}

public boolean isInRange(int i) {

return (i >= lower.get() && i <= upper.get());

}

}