org.apache.activemq.artemis.shaded.org.jgroups.util.BoundedList Maven / Gradle / Ivy
package org.apache.activemq.artemis.shaded.org.jgroups.util;
import java.util.concurrent.ConcurrentLinkedQueue;
/**
* A bounded subclass of LinkedList, oldest elements are removed once max capacity is exceeded. Note that this
* class is not synchronized (like LinkedList). Don't use this for high performance, as size() has a linear cost. But
* in most scenarios, this class is used for maintaining a history, e.g. of digests or views, so perf is not critical.
* @author Bela Ban Nov 20, 2003
*/
public class BoundedList extends ConcurrentLinkedQueue {
int max_capacity=10;
public BoundedList() {
super();
}
public BoundedList(int size) {
super();
max_capacity=size;
}
/**
* Adds an element at the tail. Removes an object from the head if capacity is exceeded
* @param obj The object to be added
*/
public boolean add(T obj) {
if(obj == null) return false;
while(size() >= max_capacity && size() > 0) {
poll();
}
return super.add(obj);
}
public boolean addIfAbsent(T obj) {
return obj != null && !contains(obj) && add(obj);
}
public T removeFromHead() {
return poll();
}
}