net.java.games.input.EventQueue Maven / Gradle / Ivy
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package net.java.games.input;
/**
* A FIFO queue for input events.
*/
public final class EventQueue {
private final Event[] queue;
private int head;
private int tail;
/**
* This is an internal method and should not be called by applications using the API
*/
public EventQueue(int size) {
queue = new Event[size + 1];
for (int i = 0; i < queue.length; i++)
queue[i] = new Event();
}
/**
* This is an internal method and should not be called by applications using the API
*/
final synchronized void add(Event event) {
queue[tail].set(event);
tail = increase(tail);
}
/**
* Check if the queue is full
* @return true if the queue is full
*/
final synchronized boolean isFull() {
return increase(tail) == head;
}
/**
* This is an internal method and should not be called by applications using the API
*/
private final int increase(int x) {
return (x + 1)%queue.length;
}
/**
* Populates the provided event with the details of the event on the head of the queue.
*
* @param event The event to populate
* @return false if there were no events left on the queue, otherwise true.
*/
public final synchronized boolean getNextEvent(Event event) {
if (head == tail)
return false;
event.set(queue[head]);
head = increase(head);
return true;
}
}