import java.util.concurrent.atomic.AtomicInteger;
public class AtomicPositiveInteger extends Number { private static final long serialVersionUID = -3038533876489105940L; private final AtomicInteger i; public AtomicPositiveInteger() {
i = new AtomicInteger();
} public AtomicPositiveInteger(int initialValue) {
i = new AtomicInteger(initialValue);
} public final int getAndIncrement() {
for (;;) {
int current = i.get();
int next = (current >= Integer.MAX_VALUE ? 0 : current + 1);
if (i.compareAndSet(current, next)) {
return current;
}
}
} public final int getAndDecrement() {
for (;;) {
int current = i.get();
int next = (current <= 0 ? Integer.MAX_VALUE : current - 1);
if (i.compareAndSet(current, next)) {
return current;
}
}
} public final int incrementAndGet() {
for (;;) {
int current = i.get();
int next = (current >= Integer.MAX_VALUE ? 0 : current + 1);
if (i.compareAndSet(current, next)) {
return next;
}
}
} public final int decrementAndGet() {
for (;;) {
int current = i.get();
int next = (current <= 0 ? Integer.MAX_VALUE : current - 1);
if (i.compareAndSet(current, next)) {
return next;
}
}
} public final int get() {
return i.get();
} public final void set(int newValue) {
if (newValue < 0) {
throw new IllegalArgumentException("new value " + newValue + " < 0");
}
i.set(newValue);
} public final int getAndSet(int newValue) {
if (newValue < 0) {
throw new IllegalArgumentException("new value " + newValue + " < 0");
}
return i.getAndSet(newValue);
} public final int getAndAdd(int delta) {
if (delta < 0) {
throw new IllegalArgumentException("delta " + delta + " < 0");
}
for (;;) {
int current = i.get();
int next = (current >= Integer.MAX_VALUE - delta + 1 ? delta - 1 : current + delta);
if (i.compareAndSet(current, next)) {
return current;
}
}
} public final int addAndGet(int delta) {
if (delta < 0) {
throw new IllegalArgumentException("delta " + delta + " < 0");
}
for (;;) {
int current = i.get();
int next = (current >= Integer.MAX_VALUE - delta + 1 ? delta - 1 : current + delta);
if (i.compareAndSet(current, next)) {
return next;
}
}
} public final boolean compareAndSet(int expect, int update) {
if (update < 0) {
throw new IllegalArgumentException("update value " + update + " < 0");
}
return i.compareAndSet(expect, update);
} public final boolean weakCompareAndSet(int expect, int update) {
if (update < 0) {
throw new IllegalArgumentException("update value " + update + " < 0");
}
return i.weakCompareAndSet(expect, update);
} public byte byteValue() {
return i.byteValue();
} public short shortValue() {
return i.shortValue();
} public int intValue() {
return i.intValue();
} public long longValue() {
return i.longValue();
} public float floatValue() {
return i.floatValue();
} public double doubleValue() {
return i.doubleValue();
} public String toString() {
return i.toString();
} @Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((i == null) ? 0 : i.hashCode());
return result;
} @Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
AtomicPositiveInteger other = (AtomicPositiveInteger) obj;
if (i == null) {
if (other.i != null) return false;
} else if (!i.equals(other.i)) return false;
return true;
} }