Example usage for java.lang.ref WeakReference WeakReference

Introduction

In this page you can find the example usage for java.lang.ref WeakReference WeakReference.

Prototype

public WeakReference(T referent, ReferenceQueue<? super T> q) 

Source Link

Document

Creates a new weak reference that refers to the given object and is registered with the given queue.

Usage

From source file:Main.java

public static void main(String[] argv) throws Exception {
    ReferenceQueue rq = new ReferenceQueue();
    WeakReference<String> wr = new WeakReference<String>("string", rq);

    while (true) {
        Reference r = rq.remove();
        if (r == wr) {
            System.out.println("no longer referenced");
        }/*from  ww  w .j a  v a  2s.  c  om*/
    }
}

---

From source file:Main.java

public static void main(String[] args) {
    ReferenceQueue referenceQueue = new ReferenceQueue();
    Object object = new Object() {
        public String toString() {
            return "Referenced Object";
        }/*w  ww  .  ja  v a  2 s. c  om*/
    };

    Object data = new Object() {
        public String toString() {
            return "Data";
        }
    };

    HashMap map = new HashMap();
    Reference reference = null;
    System.out.println("Testing WeakReference.");
    reference = new WeakReference(object, referenceQueue);

    map.put(reference, data);

    System.out.println(reference.get());
    System.out.println(map.get(reference));
    System.out.println(reference.isEnqueued());

    System.gc();
    System.out.println(reference.get());
    System.out.println(map.get(reference));
    System.out.println(reference.isEnqueued());

    object = null;
    data = null;

    System.gc();
    System.out.println(reference.get());
    System.out.println(map.get(reference));
    System.out.println(reference.isEnqueued());
}

---

From source file:WeakBag.java

/**
 * Add o to the bag and return the WeakReference that can be used to
 * remove it.//from   w  w  w .j a va 2  s .c om
 */
public WeakReference add(Object o) {
    WeakReference ans = new WeakReference(o, refQueue);
    set.add(ans);
    return ans;
}

---

From source file:WeakValueMap.java

protected Reference newReference(Object value) {
    return new WeakReference(value, refQueue);
}

---

From source file:com.mawujun.util.other.WeakReferenceMonitor.java

/**
 * Start to monitor given handle object for becoming weakly reachable.
 * When the handle isn't used anymore, the given listener will be called.
 * @param handle the object that will be monitored
 * @param listener the listener that will be called upon release of the handle
 *///from w w  w .  j a va  2s .  co m
public static void monitor(Object handle, ReleaseListener listener) {
    if (logger.isDebugEnabled()) {
        logger.debug("Monitoring handle [" + handle + "] with release listener [" + listener + "]");
    }

    // Make weak reference to this handle, so we can say when
    // handle is not used any more by polling on handleQueue.
    WeakReference weakRef = new WeakReference(handle, handleQueue);

    // Add monitored entry to internal map of all monitored entries.
    addEntry(weakRef, listener);
}

---

From source file:com.dianping.resource.io.util.WeakReferenceMonitor.java

/**
 * Start to monitor given handle object for becoming weakly reachable.
 * When the handle isn't used anymore, the given listener will be called.
 * @param handle the object that will be monitored
 * @param listener the listener that will be called upon release of the handle
 *//*  w w  w .j  a  v  a 2s.  co  m*/
public static void monitor(Object handle, ReleaseListener listener) {
    if (logger.isDebugEnabled()) {
        logger.debug("Monitoring handle [" + handle + "] with release listener [" + listener + "]");
    }

    // Make weak reference to this handle, so we can say when
    // handle is not used any more by polling on handleQueue.
    WeakReference<Object> weakRef = new WeakReference<Object>(handle, handleQueue);

    // Add monitored entry to internal map of all monitored entries.
    addEntry(weakRef, listener);
}

---