Package org.apache.cassandra.utils.concurrent

Class WeightedQueue<T>

  • All Implemented Interfaces:
    java.lang.Iterable<T>, java.util.Collection<T>, java.util.concurrent.BlockingQueue<T>, java.util.Queue<T>
    public class WeightedQueue<T>
extends java.lang.Object
implements java.util.concurrent.BlockingQueue<T>
    Weighted queue is a wrapper around any blocking queue that turns it into a blocking weighted queue. The queue will weigh each element being added and removed. Adding to the queue is blocked if adding would violate the weight bound. If an element weighs in at larger than the capacity of the queue then exactly one such element will be allowed into the queue at a time. If the weight of an object changes after it is added you are going to have a bad time. Checking weight should be cheap so memoize expensive to compute weights. If weight throws that can also result in leaked permits so it's always a good idea to memoize weight so it doesn't throw. In the interests of not writing unit tests for methods no one uses there is a lot of UnsupportedOperationException. If you need them then add them and add proper unit tests to WeightedQueueTest. "Good" tests. 100% coverage including exception paths and resource leaks.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean add​(T e)  
      boolean addAll​(java.util.Collection<? extends T> c)  
      void clear()  
      boolean contains​(java.lang.Object o)  
      boolean containsAll​(java.util.Collection<?> c)  
      int drainTo​(java.util.Collection<? super T> c)  
      int drainTo​(java.util.Collection<? super T> c, int maxElements)  
      T element()  
      boolean isEmpty()  
      java.util.Iterator<T> iterator()  
      boolean offer​(T t)  
      boolean offer​(T t, long timeout, java.util.concurrent.TimeUnit unit)  
      T peek()  
      T poll()  
      T poll​(long timeout, java.util.concurrent.TimeUnit unit)  
      void put​(T t)  
      int remainingCapacity()  
      T remove()  
      boolean remove​(java.lang.Object o)  
      boolean removeAll​(java.util.Collection<?> c)  
      boolean retainAll​(java.util.Collection<?> c)  
      int size()  
      T take()  
      java.lang.Object[] toArray()  
      <T1> T1[] toArray​(T1[] a)  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

      • Methods inherited from interface java.util.Collection

        equals, hashCode, parallelStream, removeIf, spliterator, stream, toArray

      • Methods inherited from interface java.lang.Iterable

        forEach

    • Constructor Detail

      • WeightedQueue

        public WeightedQueue​(int maxWeight)

      • WeightedQueue

        public WeightedQueue​(int maxWeight,
                     java.util.concurrent.BlockingQueue<T> queue,
                     WeightedQueue.Weigher<T> weigher)

    • Method Detail

      • add

        public boolean add​(T e)
        Specified by:
        add in interface java.util.concurrent.BlockingQueue<T>
        Specified by:
        add in interface java.util.Collection<T>
        Specified by:
        add in interface java.util.Queue<T>

      • offer

        public boolean offer​(T t)
        Specified by:
        offer in interface java.util.concurrent.BlockingQueue<T>
        Specified by:
        offer in interface java.util.Queue<T>

      • remove

        public T remove()
        Specified by:
        remove in interface java.util.Queue<T>

      • poll

        public T poll()
        Specified by:
        poll in interface java.util.Queue<T>

      • element

        public T element()
        Specified by:
        element in interface java.util.Queue<T>

      • peek

        public T peek()
        Specified by:
        peek in interface java.util.Queue<T>

      • put

        public void put​(T t)
         throws java.lang.InterruptedException
        Specified by:
        put in interface java.util.concurrent.BlockingQueue<T>
        Throws:
        java.lang.InterruptedException

      • offer

        public boolean offer​(T t,
                     long timeout,
                     java.util.concurrent.TimeUnit unit)
              throws java.lang.InterruptedException
        Specified by:
        offer in interface java.util.concurrent.BlockingQueue<T>
        Throws:
        java.lang.InterruptedException

      • take

        public T take()
       throws java.lang.InterruptedException
        Specified by:
        take in interface java.util.concurrent.BlockingQueue<T>
        Throws:
        java.lang.InterruptedException

      • poll

        public T poll​(long timeout,
              java.util.concurrent.TimeUnit unit)
       throws java.lang.InterruptedException
        Specified by:
        poll in interface java.util.concurrent.BlockingQueue<T>
        Throws:
        java.lang.InterruptedException

      • remainingCapacity

        public int remainingCapacity()
        Specified by:
        remainingCapacity in interface java.util.concurrent.BlockingQueue<T>

      • remove

        public boolean remove​(java.lang.Object o)
        Specified by:
        remove in interface java.util.concurrent.BlockingQueue<T>
        Specified by:
        remove in interface java.util.Collection<T>

      • containsAll

        public boolean containsAll​(java.util.Collection<?> c)
        Specified by:
        containsAll in interface java.util.Collection<T>

      • addAll

        public boolean addAll​(java.util.Collection<? extends T> c)
        Specified by:
        addAll in interface java.util.Collection<T>

      • removeAll

        public boolean removeAll​(java.util.Collection<?> c)
        Specified by:
        removeAll in interface java.util.Collection<T>

      • retainAll

        public boolean retainAll​(java.util.Collection<?> c)
        Specified by:
        retainAll in interface java.util.Collection<T>

      • clear

        public void clear()
        Specified by:
        clear in interface java.util.Collection<T>

      • size

        public int size()
        Specified by:
        size in interface java.util.Collection<T>

      • isEmpty

        public boolean isEmpty()
        Specified by:
        isEmpty in interface java.util.Collection<T>

      • contains

        public boolean contains​(java.lang.Object o)
        Specified by:
        contains in interface java.util.concurrent.BlockingQueue<T>
        Specified by:
        contains in interface java.util.Collection<T>

      • iterator

        public java.util.Iterator<T> iterator()
        Specified by:
        iterator in interface java.util.Collection<T>
        Specified by:
        iterator in interface java.lang.Iterable<T>

      • toArray

        public java.lang.Object[] toArray()
        Specified by:
        toArray in interface java.util.Collection<T>

      • toArray

        public <T1> T1[] toArray​(T1[] a)
        Specified by:
        toArray in interface java.util.Collection<T>

      • drainTo

        public int drainTo​(java.util.Collection<? super T> c)
        Specified by:
        drainTo in interface java.util.concurrent.BlockingQueue<T>

      • drainTo

        public int drainTo​(java.util.Collection<? super T> c,
                   int maxElements)
        Specified by:
        drainTo in interface java.util.concurrent.BlockingQueue<T>