Module com.carrotsearch.hppc
Package com.carrotsearch.hppc

Class ObjectHashSet<KType>

java.lang.Object
com.carrotsearch.hppc.ObjectHashSet<KType>
All Implemented Interfaces:
Accountable, ObjectCollection<KType>, ObjectContainer<KType>, ObjectLookupContainer<KType>, ObjectSet<KType>, Preallocable, Cloneable, Iterable<ObjectCursor<KType>>
Direct Known Subclasses:
ObjectIdentityHashSet
@Generated(date="2024-06-04T15:20:16+0200", value="KTypeHashSet.java") public class ObjectHashSet<KType> extends Object implements ObjectLookupContainer<KType>, ObjectSet<KType>, Preallocable, Cloneable, Accountable
A hash set of Objects, implemented using open addressing with linear probing for collision resolution.
See Also:

  • Field Details

    • keys

      public Object[] keys
      The hash array holding keys.

    • assigned

      protected int assigned
      The number of stored keys (assigned key slots), excluding the special "empty" key, if any.
      See Also:

    • mask

      protected int mask
      Mask for slot scans in keys.

    • resizeAt

      protected int resizeAt
      Expand (rehash) keys when assigned hits this value.

    • hasEmptyKey

      protected boolean hasEmptyKey
      Special treatment for the "empty slot" key marker.

    • loadFactor

      protected double loadFactor
      The load factor for keys.

    • iterationSeed

      protected int iterationSeed
      Seed used to ensure the hash iteration order is different from an iteration to another.

  • Constructor Details

    • ObjectHashSet

      public ObjectHashSet()
      New instance with sane defaults.
      See Also:

    • ObjectHashSet

      public ObjectHashSet(int expectedElements)
      New instance with sane defaults.
      See Also:

    • ObjectHashSet

      public ObjectHashSet(int expectedElements, double loadFactor)
      New instance with the provided defaults.
      Parameters:
      expectedElements - The expected number of elements guaranteed not to cause a rehash (inclusive).
      loadFactor - The load factor for internal buffers. Insane load factors (zero, full capacity) are rejected by verifyLoadFactor(double).

    • ObjectHashSet

      public ObjectHashSet(ObjectContainer<? extends KType> container)
      New instance copying elements from another ObjectContainer.

  • Method Details

    • add

      public boolean add(KType key)
      Adds k to the set.
      Specified by:
      add in interface ObjectSet<KType>
      Returns:
      Returns true if this element was not part of the set before. Returns false if an equal element is already part of the set, does not replace the existing element with the argument.

    • addAll

      @SafeVarargs public final int addAll(KType... elements)
      Adds all elements from the given list (vararg) to this set.
      Returns:
      Returns the number of elements actually added as a result of this call (not previously present in the set).

    • addAll

      public int addAll(ObjectContainer<? extends KType> container)
      Adds all elements from the given ObjectContainer to this set.
      Specified by:
      addAll in interface ObjectSet<KType>
      Returns:
      Returns the number of elements actually added as a result of this call (not previously present in the set).

    • addAll

      public int addAll(Iterable<? extends ObjectCursor<? extends KType>> iterable)
      Adds all elements from the given iterable to this set.
      Returns:
      Returns the number of elements actually added as a result of this call (not previously present in the set).

    • toArray

      public Object[] toArray()
      Default implementation of copying to an array.
      Specified by:
      toArray in interface ObjectContainer<KType>

    • remove

      public boolean remove(KType key)
      An alias for the (preferred) removeAll(KType).

    • removeAll

      public int removeAll(KType key)
      Removes all occurrences of e from this collection.
      Specified by:
      removeAll in interface ObjectCollection<KType>
      Parameters:
      key - Element to be removed from this collection, if present.
      Returns:
      The number of removed elements as a result of this call.

    • removeAll

      public int removeAll(ObjectContainer<? super KType> other)
      Removes all keys present in a given container.
      Returns:
      Returns the number of elements actually removed as a result of this call.

    • removeAll

      public int removeAll(ObjectPredicate<? super KType> predicate)
      Removes all elements in this collection for which the given predicate returns true .
      Specified by:
      removeAll in interface ObjectCollection<KType>
      Returns:
      Returns the number of removed elements.

    • contains

      public boolean contains(KType key)
      Lookup a given element in the container. This operation has no speed guarantees (may be linear with respect to the size of this container).
      Specified by:
      contains in interface ObjectContainer<KType>
      Specified by:
      contains in interface ObjectLookupContainer<KType>
      Returns:
      Returns true if this container has an element equal to e.

    • clear

      public void clear()
      Removes all elements from this collection.
      Specified by:
      clear in interface ObjectCollection<KType>
      See Also:

    • release

      public void release()
      Removes all elements from the collection and additionally releases any internal buffers. Typically, if the object is to be reused, a simple ObjectCollection.clear() should be a better alternative since it'll avoid reallocation.
      Specified by:
      release in interface ObjectCollection<KType>
      See Also:

    • isEmpty

      public boolean isEmpty()
      Shortcut for size() == 0.
      Specified by:
      isEmpty in interface ObjectContainer<KType>

    • ensureCapacity

      public void ensureCapacity(int expectedElements)
      Ensure this container can hold at least the given number of elements without resizing its buffers.
      Specified by:
      ensureCapacity in interface Preallocable
      Parameters:
      expectedElements - The total number of elements, inclusive.

    • size

      public int size()
      Return the current number of elements in this container. The time for calculating the container's size may take O(n) time, although implementing classes should try to maintain the current size and return in constant time.
      Specified by:
      size in interface ObjectContainer<KType>

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • clone

      public ObjectHashSet<KType> clone()
      Overrides:
      clone in class Object

    • iterator

      public Iterator<ObjectCursor<KType>> iterator()
      Returns an iterator to a cursor traversing the collection. The order of traversal is not defined. More than one cursor may be active at a time. The behavior of iterators is undefined if structural changes are made to the underlying collection.

      The iterator is implemented as a cursor and it returns the same cursor instance on every call to Iterator.next() (to avoid boxing of primitive types). To read the current list's value (or index in the list) use the cursor's public fields. An example is shown below. 

       for (ObjectCursor<Object> c : container) {
   System.out.println("index=" + c.index + " value=" + c.value);
 }
      Specified by:
      iterator in interface Iterable<KType>
      Specified by:
      iterator in interface ObjectContainer<KType>

    • ramBytesAllocated

      public long ramBytesAllocated()
      Description copied from interface: Accountable
      Allocated memory estimation
      Specified by:
      ramBytesAllocated in interface Accountable
      Returns:
      Ram allocated in bytes

    • ramBytesUsed

      public long ramBytesUsed()
      Description copied from interface: Accountable
      Bytes that is actually been used
      Specified by:
      ramBytesUsed in interface Accountable
      Returns:
      Ram used in bytes

    • nextIterationSeed

      protected int nextIterationSeed()
      Provides the next iteration seed used to build the iteration starting slot and offset increment. This method does not need to be synchronized, what matters is that each thread gets a sequence of varying seeds.

    • forEach

      public <T extends ObjectProcedure<? super KType>> T forEach(T procedure)
      Applies a procedure to all container elements. Returns the argument (any subclass of ObjectProcedure. This lets the caller to call methods of the argument by chaining the call (even if the argument is an anonymous type) to retrieve computed values, for example (IntContainer): 
       int count = container.forEach(new IntProcedure() {
   int count; // this is a field declaration in an anonymous class.

   public void apply(int value) {
     count++;
   }
 }).count;
      Specified by:
      forEach in interface ObjectContainer<KType>

    • forEach

      public <T extends ObjectPredicate<? super KType>> T forEach(T predicate)
      Applies a predicate to container elements as long, as the predicate returns true. The iteration is interrupted otherwise.
      Specified by:
      forEach in interface ObjectContainer<KType>

    • from

      @SafeVarargs public static <KType> ObjectHashSet<KType> from(KType... elements)
      Create a set from a variable number of arguments or an array of Object. The elements are copied from the argument to the internal buffer.

    • hashKey

      protected int hashKey(KType key)
      Returns a hash code for the given key.

      The output from this function should evenly distribute keys across the entire integer range.

    • indexOf

      public int indexOf(KType key)
      Returns a logical "index" of a given key that can be used to speed up follow-up logic in certain scenarios (conditional logic).

      The semantics of "indexes" are not strictly defined. Indexes may (and typically won't be) contiguous.

      The index is valid only between modifications (it will not be affected by read-only operations).

      Parameters:
      key - The key to locate in the set.
      Returns:
      A non-negative value of the logical "index" of the key in the set or a negative value if the key did not exist.
      See Also:

    • indexExists

      public boolean indexExists(int index)
      Parameters:
      index - The index of a given key, as returned from indexOf(KType).
      Returns:
      Returns true if the index corresponds to an existing key or false otherwise. This is equivalent to checking whether the index is a positive value (existing keys) or a negative value (non-existing keys).
      See Also:

    • indexGet

      public KType indexGet(int index)
      Returns the exact value of the existing key. This method makes sense for sets of objects which define custom key-equality relationship.
      Parameters:
      index - The index of an existing key.
      Returns:
      Returns the equivalent key currently stored in the set.
      Throws:
      AssertionError - If assertions are enabled and the index does not correspond to an existing key.
      See Also:

    • indexReplace

      public KType indexReplace(int index, KType equivalentKey)
      Replaces the existing equivalent key with the given one and returns any previous value stored for that key.
      Parameters:
      index - The index of an existing key.
      equivalentKey - The key to put in the set as a replacement. Must be equivalent to the key currently stored at the provided index.
      Returns:
      Returns the previous key stored in the set.
      Throws:
      AssertionError - If assertions are enabled and the index does not correspond to an existing key.
      See Also:

    • indexInsert

      public void indexInsert(int index, KType key)
      Inserts a key for an index that is not present in the set. This method may help in avoiding double recalculation of the key's hash.
      Parameters:
      index - The index of a previously non-existing key, as returned from indexOf(KType).
      Throws:
      AssertionError - If assertions are enabled and the index does not correspond to an existing key.
      See Also:

    • indexRemove

      public void indexRemove(int index)
      Removes a key at an index previously acquired from indexOf(KType).
      Parameters:
      index - The index of the key to remove, as returned from indexOf(KType).
      Throws:
      AssertionError - If assertions are enabled and the index does not correspond to an existing key.
      See Also:

    • visualizeKeyDistribution

      public String visualizeKeyDistribution(int characters)
      Description copied from interface: ObjectSet
      Visually depict the distribution of keys.
      Specified by:
      visualizeKeyDistribution in interface ObjectSet<KType>
      Parameters:
      characters - The number of characters to "squeeze" the entire buffer into.
      Returns:
      Returns a sequence of characters where '.' depicts an empty fragment of the internal buffer and 'X' depicts full or nearly full capacity within the buffer's range and anything between 1 and 9 is between.

    • verifyLoadFactor

      protected double verifyLoadFactor(double loadFactor)
      Validate load factor range and return it. Override and suppress if you need insane load factors.

    • rehash

      protected void rehash(KType[] fromKeys)
      Rehash from old buffers to new buffers.

    • allocateBuffers

      protected void allocateBuffers(int arraySize)
      Allocate new internal buffers. This method attempts to allocate and assign internal buffers atomically (either allocations succeed or not).

    • allocateThenInsertThenRehash

      protected void allocateThenInsertThenRehash(int slot, KType pendingKey)
      This method is invoked when there is a new key to be inserted into the buffer but there is not enough empty slots to do so.

      New buffers are allocated. If this succeeds, we know we can proceed with rehashing so we assign the pending element to the previous buffer (possibly violating the invariant of having at least one empty slot) and rehash all keys, substituting new buffers at the end.

    • shiftConflictingKeys

      protected void shiftConflictingKeys(int gapSlot)
      Shift all the slot-conflicting keys allocated to (and including) slot.

    • removeAll

      public int removeAll(ObjectLookupContainer<? super KType> c)
      Default implementation uses a predicate for removal.
      Specified by:
      removeAll in interface ObjectCollection<KType>
      Returns:
      Returns the number of removed elements.

    • retainAll

      public int retainAll(ObjectLookupContainer<? super KType> c)
      Default implementation uses a predicate for retaining.
      Specified by:
      retainAll in interface ObjectCollection<KType>
      Returns:
      Returns the number of removed elements.

    • retainAll

      public int retainAll(ObjectPredicate<? super KType> predicate)
      Default implementation redirects to ObjectCollection.removeAll(ObjectPredicate) and negates the predicate.
      Specified by:
      retainAll in interface ObjectCollection<KType>
      Returns:
      Returns the number of removed elements.

    • toArray

      public <T> T[] toArray(Class<T> componentClass)
      Description copied from interface: ObjectContainer
      Copies all elements of this container to a dynamically created array of the given component type.
      Specified by:
      toArray in interface ObjectContainer<KType>

    • toString

      public String toString()
      Convert the contents of this container to a human-friendly string.
      Overrides:
      toString in class Object

    • equals

      protected boolean equals(Object v1, Object v2)