Package com.carrotsearch.hppc

Class IntHashSet

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected int assigned
      The number of stored keys (assigned key slots), excluding the special "empty" key, if any.
      protected boolean hasEmptyKey
      Special treatment for the "empty slot" key marker.
      protected int keyMixer
      We perturb hash values with a container-unique seed to avoid problems with nearly-sorted-by-hash values on iterations.
      int[] keys
      The hash array holding keys.
      protected double loadFactor
      The load factor for keys.
      protected int mask
      Mask for slot scans in keys.
      protected HashOrderMixingStrategy orderMixer
      Per-instance hash order mixing strategy.
      protected int resizeAt
      Expand (rehash) keys when assigned hits this value.

    • Constructor Summary

      Constructors 
      Constructor Description
      IntHashSet()
      New instance with sane defaults.
      IntHashSet​(int expectedElements)
      New instance with sane defaults.
      IntHashSet​(int expectedElements, double loadFactor)
      New instance with sane defaults.
      IntHashSet​(int expectedElements, double loadFactor, HashOrderMixingStrategy orderMixer)
      New instance with the provided defaults.
      IntHashSet​(IntContainer container)
      New instance copying elements from another IntContainer.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean add​(int key)
      Adds k to the set.
      int addAll​(int... elements)
      Adds all elements from the given list (vararg) to this set.
      int addAll​(IntContainer container)
      Adds all elements from the given IntContainer to this set.
      int addAll​(Iterable<? extends IntCursor> iterable)
      Adds all elements from the given iterable to this set.
      protected void allocateBuffers​(int arraySize)
      Allocate new internal buffers.
      protected void allocateThenInsertThenRehash​(int slot, int 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.
      void clear()
      Removes all elements from this collection.
      IntHashSet clone()
      boolean contains​(int key)
      Lookup a given element in the container.
      void ensureCapacity​(int expectedElements)
      Ensure this container can hold at least the given number of elements without resizing its buffers.
      boolean equals​(Object obj)
      <T extends IntProcedure>
      T      		 forEach​(T procedure)
      Applies a procedure to all container elements.
      static IntHashSet from​(int... elements)
      Create a set from a variable number of arguments or an array of int.
      int hashCode()
      protected int hashKey​(int key)
      Returns a hash code for the given key.
      boolean indexExists​(int index)  
      int indexGet​(int index)
      Returns the exact value of the existing key.
      void indexInsert​(int index, int key)
      Inserts a key for an index that is not present in the set.
      int indexOf​(int key)
      Returns a logical "index" of a given key that can be used to speed up follow-up logic in certain scenarios (conditional logic).
      int indexReplace​(int index, int equivalentKey)
      Replaces the existing equivalent key with the given one and returns any previous value stored for that key.
      boolean isEmpty()
      Shortcut for size() == 0.
      Iterator<IntCursor> iterator()
      Returns an iterator to a cursor traversing the collection.
      protected void rehash​(int[] fromKeys)
      Rehash from old buffers to new buffers.
      void release()
      Removes all elements from the collection and additionally releases any internal buffers.
      boolean remove​(int key)
      An alias for the (preferred) removeAll(int).
      int removeAll​(int key)
      Removes all occurrences of e from this collection.
      int removeAll​(IntLookupContainer c)
      Default implementation uses a predicate for removal.
      int removeAll​(IntPredicate predicate)
      Removes all elements in this collection for which the given predicate returns true.
      int retainAll​(IntLookupContainer c)
      Default implementation uses a predicate for retaining.
      int retainAll​(IntPredicate predicate)
      Default implementation redirects to IntCollection.removeAll(IntPredicate) and negates the predicate.
      protected void shiftConflictingKeys​(int gapSlot)
      Shift all the slot-conflicting keys allocated to (and including) slot.
      int size()
      Return the current number of elements in this container.
      int[] toArray()
      Default implementation of copying to an array.
      String toString()
      Convert the contents of this container to a human-friendly string.
      protected double verifyLoadFactor​(double loadFactor)
      Validate load factor range and return it.
      String visualizeKeyDistribution​(int characters)
      Visually depict the distribution of keys.

    • Field Detail

      • keys

        public int[] 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:
        size(), hasEmptyKey

      • mask

        protected int mask
        Mask for slot scans in keys.

      • keyMixer

        protected int keyMixer
        We perturb hash values with a container-unique seed to avoid problems with nearly-sorted-by-hash values on iterations.
        See Also:
        hashKey(int), "http://issues.carrot2.org/browse/HPPC-80", "http://issues.carrot2.org/browse/HPPC-103"

      • 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.

    • Method Detail

      • add

        public boolean add​(int key)
        Adds k to the set.
        Specified by:
        add in interface IntSet
        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

        public final int addAll​(int... 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​(IntContainer container)
        Adds all elements from the given IntContainer 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​(Iterable<? extends IntCursor> 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 int[] toArray()
        Default implementation of copying to an array.
        Specified by:
        toArray in interface IntContainer

      • remove

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

      • removeAll

        public int removeAll​(int key)
        Removes all occurrences of e from this collection.
        Specified by:
        removeAll in interface IntCollection
        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​(IntPredicate predicate)
        Removes all elements in this collection for which the given predicate returns true.
        Specified by:
        removeAll in interface IntCollection
        Returns:
        Returns the number of removed elements.

      • contains

        public boolean contains​(int 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 IntContainer
        Specified by:
        contains in interface IntLookupContainer
        Returns:
        Returns true if this container has an element equal to e.

      • 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 IntCollection.clear() should be a better alternative since it'll avoid reallocation.
        Specified by:
        release in interface IntCollection
        See Also:
        IntCollection.clear()

      • isEmpty

        public boolean isEmpty()
        Shortcut for size() == 0.
        Specified by:
        isEmpty in interface IntContainer

      • 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 IntContainer

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object

      • iterator

        public Iterator<IntCursor> 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 (IntCursor<int> c : container) {
   System.out.println("index=" + c.index + " value=" + c.value);
 }
        Specified by:
        iterator in interface IntContainer
        Specified by:
        iterator in interface Iterable<IntCursor>

      • forEach

        public <T extends IntProcedure> T forEach​(T procedure)
        Applies a procedure to all container elements. Returns the argument (any subclass of IntProcedure. 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 IntContainer

      • forEach

        public <T extends IntPredicate> 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 IntContainer

      • from

        public static IntHashSet from​(int... elements)
        Create a set from a variable number of arguments or an array of int. The elements are copied from the argument to the internal buffer.

      • hashKey

        protected int hashKey​(int key)
        Returns a hash code for the given key. The default implementation mixes the hash of the key with keyMixer to differentiate hash order of keys between hash containers. Helps alleviate problems resulting from linear conflict resolution in open addressing. The output from this function should evenly distribute keys across the entire integer range.

      • indexOf

        public int indexOf​(int 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(int), indexGet(int), indexInsert(int, int), indexReplace(int, int)

      • indexExists

        public boolean indexExists​(int index)
        Parameters:
        index - The index of a given key, as returned from indexOf(int).
        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:
        indexOf(int)

      • indexGet

        public int 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:
        indexOf(int)

      • indexReplace

        public int indexReplace​(int index,
                        int 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:
        indexOf(int)

      • indexInsert

        public void indexInsert​(int index,
                        int 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(int).
        Throws:
        AssertionError - If assertions are enabled and the index does not correspond to an existing key.
        See Also:
        indexOf(int)

      • visualizeKeyDistribution

        public String visualizeKeyDistribution​(int characters)
        Description copied from interface: IntSet
        Visually depict the distribution of keys.
        Specified by:
        visualizeKeyDistribution in interface IntSet
        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​(int[] 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,
                                            int 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​(IntLookupContainer c)
        Default implementation uses a predicate for removal.
        Specified by:
        removeAll in interface IntCollection
        Returns:
        Returns the number of removed elements.

      • retainAll

        public int retainAll​(IntLookupContainer c)
        Default implementation uses a predicate for retaining.
        Specified by:
        retainAll in interface IntCollection
        Returns:
        Returns the number of removed elements.

      • toString

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