Package org.apache.commons.collections.buffer

Class PriorityBuffer

java.lang.Object
java.util.AbstractCollection
org.apache.commons.collections.buffer.PriorityBuffer
All Implemented Interfaces:
Serializable, Iterable, Collection, Buffer
@Deprecated(since="2021-04-30") public class PriorityBuffer extends AbstractCollection implements Buffer, Serializable
Deprecated.
Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
Binary heap implementation of Buffer that provides for removal based on Comparator ordering.

The removal order of a binary heap is based on either the natural sort order of its elements or a specified Comparator. The remove() method always returns the first element as determined by the sort order. (The ascendingOrder flag in the constructors can be used to reverse the sort order, in which case remove() will always remove the last element.) The removal order is not the same as the order of iteration; elements are returned by the iterator in no particular order.

The add(Object) and remove() operations perform in logarithmic time. The get() operation performs in constant time. All other operations perform in linear time or worse.

Note that this implementation is not synchronized. Use BufferUtils.synchronizedBuffer(Buffer) or SynchronizedBuffer.decorate(Buffer) to provide synchronized access to a PriorityBuffer: 

  Buffer heap = SynchronizedBuffer.decorate(new PriorityBuffer());

This class is Serializable from Commons Collections 3.2.

Since:
Commons Collections 3.0 (previously BinaryHeap v1.0)
See Also:

  • Constructor Details

    • PriorityBuffer

      public PriorityBuffer()
      Deprecated.
      Constructs a new empty buffer that sorts in ascending order by the natural order of the objects added.

    • PriorityBuffer

      public PriorityBuffer(Comparator comparator)
      Deprecated.
      Constructs a new empty buffer that sorts in ascending order using the specified comparator.
      Parameters:
      comparator - the comparator used to order the elements, null means use natural order

    • PriorityBuffer

      public PriorityBuffer(boolean ascendingOrder)
      Deprecated.
      Constructs a new empty buffer specifying the sort order and using the natural order of the objects added.
      Parameters:
      ascendingOrder - if true the heap is created as a minimum heap; otherwise, the heap is created as a maximum heap

    • PriorityBuffer

      public PriorityBuffer(boolean ascendingOrder, Comparator comparator)
      Deprecated.
      Constructs a new empty buffer specifying the sort order and comparator.
      Parameters:
      ascendingOrder - true to use the order imposed by the given comparator; false to reverse that order
      comparator - the comparator used to order the elements, null means use natural order

    • PriorityBuffer

      public PriorityBuffer(int capacity)
      Deprecated.
      Constructs a new empty buffer that sorts in ascending order by the natural order of the objects added, specifying an initial capacity.
      Parameters:
      capacity - the initial capacity for the buffer, greater than zero
      Throws:
      IllegalArgumentException - if capacity is <= 0

    • PriorityBuffer

      public PriorityBuffer(int capacity, Comparator comparator)
      Deprecated.
      Constructs a new empty buffer that sorts in ascending order using the specified comparator and initial capacity.
      Parameters:
      capacity - the initial capacity for the buffer, greater than zero
      comparator - the comparator used to order the elements, null means use natural order
      Throws:
      IllegalArgumentException - if capacity is <= 0

    • PriorityBuffer

      public PriorityBuffer(int capacity, boolean ascendingOrder)
      Deprecated.
      Constructs a new empty buffer that specifying initial capacity and sort order, using the natural order of the objects added.
      Parameters:
      capacity - the initial capacity for the buffer, greater than zero
      ascendingOrder - if true the heap is created as a minimum heap; otherwise, the heap is created as a maximum heap.
      Throws:
      IllegalArgumentException - if capacity is <= 0

    • PriorityBuffer

      public PriorityBuffer(int capacity, boolean ascendingOrder, Comparator comparator)
      Deprecated.
      Constructs a new empty buffer that specifying initial capacity, sort order and comparator.
      Parameters:
      capacity - the initial capacity for the buffer, greater than zero
      ascendingOrder - true to use the order imposed by the given comparator; false to reverse that order
      comparator - the comparator used to order the elements, null means use natural order
      Throws:
      IllegalArgumentException - if capacity is <= 0

  • Method Details

    • isAscendingOrder

      public boolean isAscendingOrder()
      Deprecated.
      Checks whether the heap is ascending or descending order.
      Returns:
      true if ascending order (a min heap)

    • comparator

      public Comparator comparator()
      Deprecated.
      Gets the comparator being used for this buffer, null is natural order.
      Returns:
      the comparator in use, null is natural order

    • size

      public int size()
      Deprecated.
      Returns the number of elements in this buffer.
      Specified by:
      size in interface Collection
      Specified by:
      size in class AbstractCollection
      Returns:
      the number of elements in this buffer

    • clear

      public void clear()
      Deprecated.
      Clears all elements from the buffer.
      Specified by:
      clear in interface Collection
      Overrides:
      clear in class AbstractCollection

    • add

      public boolean add(Object element)
      Deprecated.
      Adds an element to the buffer.

      The element added will be sorted according to the comparator in use.

      Specified by:
      add in interface Collection
      Overrides:
      add in class AbstractCollection
      Parameters:
      element - the element to be added
      Returns:
      true always

    • get

      public Object get()
      Deprecated.
      Gets the next element to be removed without actually removing it (peek).
      Specified by:
      get in interface Buffer
      Returns:
      the next element
      Throws:
      BufferUnderflowException - if the buffer is empty

    • remove

      public Object remove()
      Deprecated.
      Gets and removes the next element (pop).
      Specified by:
      remove in interface Buffer
      Returns:
      the next element
      Throws:
      BufferUnderflowException - if the buffer is empty

    • iterator

      public Iterator iterator()
      Deprecated.
      Returns an iterator over this heap's elements.
      Specified by:
      iterator in interface Collection
      Specified by:
      iterator in interface Iterable
      Specified by:
      iterator in class AbstractCollection
      Returns:
      an iterator over this heap's elements

    • toString

      public String toString()
      Deprecated.
      Returns a string representation of this heap. The returned string is similar to those produced by standard JDK collections.
      Overrides:
      toString in class AbstractCollection
      Returns:
      a string representation of this heap