Package com.carrotsearch.hppc

Class ObjectWormSet<KType>

java.lang.Object
com.carrotsearch.hppc.ObjectWormSet<KType>
All Implemented Interfaces:
Accountable, ObjectCollection<KType>, ObjectContainer<KType>, ObjectLookupContainer<KType>, ObjectSet<KType>, Preallocable, Cloneable, Iterable<ObjectCursor<KType>>
@Generated(date="2021-12-15T09:45:39+0100", value="KTypeWormSet.java") public class ObjectWormSet<KType> extends Object implements ObjectLookupContainer<KType>, ObjectSet<KType>, Preallocable, Cloneable, Accountable
A hash set of Objects, implemented using Worm Hashing strategy.

This strategy is appropriate for a medium sized set (less than 2M keys). It takes more time to put keys in the set because it maintains chains of keys having the same hash. Then the lookup speed is fast even if the set is heavy loaded or hashes are clustered. On average it takes slightly more memory than ObjectHashSet: heavier but the load factor is higher (it varies around 80%) so it enlarges later.

See Also:

  • Field Details

    • keys

      public Object[] keys
      The array holding keys.

    • next

      public byte[] next
      abs(next[i])=offset to next chained entry index.

      next[i]=0 for free bucket.

      The offset is always forward, and the array is considered circular, meaning that an entry at the end of the array may point to an entry at the beginning with a positive offset.

      The offset is always forward, but the sign of the offset encodes head/tail of chain. next[i] > 0 for the first head-of-chain entry (within [1,WormUtil.maxOffset(int)]), next[i] < 0 for the subsequent tail-of-chain entries (within [-WormUtil.maxOffset(int),-1]. For the last entry in the chain, abs(next[i])=WormUtil.END_OF_CHAIN.

    • size

      protected int size
      Set size (number of entries).

    • iterationSeed

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

  • Constructor Details

    • ObjectWormSet

      public ObjectWormSet()
      New instance with sane defaults.

    • ObjectWormSet

      public ObjectWormSet(int expectedElements)
      New instance with the provided defaults.

      There is no load factor parameter as this set enlarges automatically. In practice the load factor varies around 80% (between 75% and 90%). The load factor is 100% for tiny sets.

      Parameters:
      expectedElements - The expected number of elements. The capacity of the set is calculated based on it.

    • ObjectWormSet

      public ObjectWormSet(ObjectContainer<? extends KType> container)
      Creates a new instance from all elements of another container.

  • Method Details

    • from

      @SafeVarargs public static <KType> ObjectWormSet<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.

    • clone

      public ObjectWormSet<KType> clone()
      Clones this set. The cloning operation is efficient because it copies directly the internal arrays, without having to put elements in the cloned set. The cloned set has the same elements and the same capacity as this set.
      Overrides:
      clone in class Object
      Returns:
      A shallow copy of this set.

    • 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>

    • isEmpty

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

    • 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.

    • 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).

    • 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.

    • 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>

    • 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>

    • 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:

    • equals

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

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • hashKey

      protected int hashKey(KType key)

    • 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:

    • toString

      public String toString()
      Convert the contents of this container to a human-friendly string.

    • 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.

    • visualizeKeyDistribution

      public String visualizeKeyDistribution(int characters)
      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.

    • ramBytesAllocated

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

    • ramBytesUsed

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

    • allocateBuffers

      protected void allocateBuffers(int capacity)

    • 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.

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

    • 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>

    • equals

      protected boolean equals(Object v1, Object v2)