blob: 0e91a44bf5d401b87416b1d0d76cbca12411774b (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.yolean.concurrent;
import java.util.Iterator;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.function.Supplier;
/**
* A pool of a resource. This create new instances of the resource on request until enough are created
* to deliver a unique one to all threads needing one concurrently and then reuse those instances
* in subsequent requests.
*
* @author baldersheim
*/
public class ConcurrentResourcePool<T> implements Iterable<T> {
private final Queue<T> pool = new ConcurrentLinkedQueue<>();
private final Supplier<T> factory;
public ConcurrentResourcePool(Supplier<T> factory) {
this.factory = factory;
}
public void preallocate(int instances) {
for (int i = 0; i < instances; i++) {
pool.offer(factory.get());
}
}
/**
* Allocates an instance of the resource to the requestor.
* The resource will be allocated exclusively to the requestor until it calls free(instance).
*
* @return a reused or newly created instance of the resource
*/
public final T alloc() {
T e = pool.poll();
return e != null ? e : factory.get();
}
/** Frees an instance previously acquired bty alloc */
public final void free(T e) {
pool.offer(e);
}
@Override
public Iterator<T> iterator() {
return pool.iterator();
}
}
|
