org.glassfish.jersey.internal.util.LazyUid Maven / Gradle / Ivy
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package org.glassfish.jersey.internal.util;
import java.io.Serializable;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicReference;
/**
* Lazily initialized, thread-safe, random UUID. Useful for identifying instances
* for logging & debugging purposes.
*
* The UUID value gets initialized with the first call to {@link #value()} method.
* Once initialized, the UUID value stays the same.
*
* @author Marek Potociar (marek.potociar at oracle.com)
*/
public class LazyUid implements Serializable {
private static final long serialVersionUID = 4618609413877136867L;
private final AtomicReference uid = new AtomicReference();
/**
* Return UUID value. The returned value is never {@code null}.
*
* @return UUID value.
*/
public String value() {
if (uid.get() == null) {
uid.compareAndSet(null, UUID.randomUUID().toString());
}
return uid.get();
}
@Override
public boolean equals(Object that) {
if (that == null) {
return false;
}
if (getClass() != that.getClass()) {
return false;
}
final LazyUid other = (LazyUid) that;
return this.value().equals(other.value());
}
@Override
public int hashCode() {
int hash = 7;
hash = 73 * hash + this.value().hashCode();
return hash;
}
@Override
public String toString() {
return value();
}
}