Package fr.gouv.vitam.storage.offers.tape.cache

Class LRUQueue<T>

  • Type Parameters:
    T - the type of elements maintained by this queue.
    @NotThreadSafe
public class LRUQueue<T>
extends java.lang.Object
    Sorted Least Recently Used (LRU) queue implementation. Entries are sorted using long timestamp. Oldest entries are returned first. The LRUQueue class is NOT thread safe. Concurrent access must be synchronized.

    • Constructor Summary

      Constructors 
      Constructor Description
      LRUQueue()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void add​(T entry, long timestamp)
      Adds an entry to the queue.
      boolean contains​(T entry)
      Returns true if this queue contains the specified entry.
      boolean isEmpty()  
      java.util.Iterator<T> iterator()
      Returns an iterator over the queue.
      boolean remove​(T entry)
      Removes an entry from the queue
      int size()  
      boolean update​(T entry, long timestamp)
      Updates an existing entry timestamp

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • LRUQueue

        public LRUQueue()

    • Method Detail

      • add

        public void add​(T entry,
                long timestamp)
         throws java.lang.IllegalArgumentException
        Adds an entry to the queue. If entry already exists, an IllegalArgumentException is thrown.
        Parameters:
        entry - the entry to add to the queue
        timestamp - the entry timestamp to set
        Throws:
        java.lang.IllegalArgumentException - if entry already exists

      • update

        public boolean update​(T entry,
                      long timestamp)
        Updates an existing entry timestamp
        Parameters:
        entry - the existing entry to update
        timestamp - the entry timestamp to update
        Returns:
        true is entry has been updated, false if entry was not found.

      • contains

        public boolean contains​(T entry)
        Returns true if this queue contains the specified entry.
        Parameters:
        entry - the entry whose presence in this queue is to be tested
        Returns:
        true is the entry exists in the queue.

      • remove

        public boolean remove​(T entry)
        Removes an entry from the queue
        Parameters:
        entry - the entry to remove
        Returns:
        true is the entry was removed, false otherwise.

      • iterator

        public java.util.Iterator<T> iterator()
        Returns an iterator over the queue. Older entries are returned first. Iterator supports Iterator.remove() to remove entries while iterating.
        Returns:
        An iterator over the elements of the queue.

      • isEmpty

        public boolean isEmpty()
        Returns:
        true is the queue is empty, false otherwise.

      • size

        public int size()
        Returns:
        queue size