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

Class ShortObjectHashMap<VType>

java.lang.Object
com.carrotsearch.hppc.ShortObjectHashMap<VType>
All Implemented Interfaces:
Accountable, Preallocable, ShortObjectAssociativeContainer<VType>, ShortObjectMap<VType>, Cloneable, Iterable<ShortObjectCursor<VType>>
@Generated(date="2024-06-04T15:20:16+0200", value="KTypeVTypeHashMap.java") public class ShortObjectHashMap<VType> extends Object implements ShortObjectMap<VType>, Preallocable, Cloneable, Accountable
A hash map of short to Object, implemented using open addressing with linear probing for collision resolution. Supports null values.
See Also:

  • Field Details

    • keys

      public short[] keys
      The array holding keys.

    • values

      public Object[] values
      The array holding values.

    • assigned

      protected int assigned
      The number of stored keys (assigned key slots), excluding the special "empty" key, if any (use size() instead).
      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

    • ShortObjectHashMap

      public ShortObjectHashMap()
      New instance with sane defaults.

    • ShortObjectHashMap

      public ShortObjectHashMap(int expectedElements)
      New instance with sane defaults.
      Parameters:
      expectedElements - The expected number of elements guaranteed not to cause buffer expansion (inclusive).

    • ShortObjectHashMap

      public ShortObjectHashMap(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).

    • ShortObjectHashMap

      public ShortObjectHashMap(ShortObjectAssociativeContainer<? extends VType> container)
      Create a hash map from all key-value pairs of another container.

  • Method Details

    • put

      public VType put(short key, VType value)
      Place a given key and value in the container.
      Specified by:
      put in interface ShortObjectMap<VType>
      Returns:
      The value previously stored under the given key in the map is returned.

    • putAll

      public int putAll(ShortObjectAssociativeContainer<? extends VType> container)
      Puts all keys from another container to this map, replacing the values of existing keys, if such keys are present.
      Specified by:
      putAll in interface ShortObjectMap<VType>
      Returns:
      Returns the number of keys added to the map as a result of this call (not previously present in the map). Values of existing keys are overwritten.

    • putAll

      public int putAll(Iterable<? extends ShortObjectCursor<? extends VType>> iterable)
      Puts all key/value pairs from a given iterable into this map.
      Specified by:
      putAll in interface ShortObjectMap<VType>
      Returns:
      Returns the number of keys added to the map as a result of this call (not previously present in the map). Values of existing keys are overwritten.

    • remove

      public VType remove(short key)
      Remove all values at the given key. The default value for the key type is returned if the value does not exist in the map.
      Specified by:
      remove in interface ShortObjectMap<VType>

    • removeAll

      public int removeAll(ShortContainer other)
      Removes all keys (and associated values) present in a given container. An alias to: 
       keys().removeAll(container)
      but with no additional overhead.
      Specified by:
      removeAll in interface ShortObjectAssociativeContainer<VType>
      Returns:
      Returns the number of elements actually removed as a result of this call.

    • removeAll

      public int removeAll(ShortObjectPredicate<? super VType> predicate)
      Removes all keys (and associated values) for which the predicate returns true.
      Specified by:
      removeAll in interface ShortObjectAssociativeContainer<VType>
      Returns:
      Returns the number of elements actually removed as a result of this call.

    • removeAll

      public int removeAll(ShortPredicate predicate)
      Removes all keys (and associated values) for which the predicate returns true.
      Specified by:
      removeAll in interface ShortObjectAssociativeContainer<VType>
      Returns:
      Returns the number of elements actually removed as a result of this call.

    • get

      public VType get(short key)
      Specified by:
      get in interface ShortObjectMap<VType>
      Returns:
      Returns the value associated with the given key or the default value for the value type, if the key is not associated with any value. For numeric value types, this default value is 0, for object types it is null.

    • getOrDefault

      public VType getOrDefault(short key, VType defaultValue)
      Specified by:
      getOrDefault in interface ShortObjectMap<VType>
      Returns:
      Returns the value associated with the given key or the provided default value if the key is not associated with any value.

    • containsKey

      public boolean containsKey(short key)
      Returns true if this container has an association to a value for the given key.
      Specified by:
      containsKey in interface ShortObjectAssociativeContainer<VType>

    • indexOf

      public int indexOf(short key)
      Returns a logical "index" of a given key that can be used to speed up follow-up value setters or getters 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 map modifications (it will not be affected by read-only operations like iteration or value retrievals).

      Specified by:
      indexOf in interface ShortObjectMap<VType>
      Parameters:
      key - The key to locate in the map.
      Returns:
      A non-negative value of the logical "index" of the key in the map or a negative value if the key did not exist.
      See Also:

    • indexExists

      public boolean indexExists(int index)
      Specified by:
      indexExists in interface ShortObjectMap<VType>
      Parameters:
      index - The index of a given key, as returned from ShortObjectMap.indexOf(short).
      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 VType indexGet(int index)
      Returns the value associated with an existing key.
      Specified by:
      indexGet in interface ShortObjectMap<VType>
      Parameters:
      index - The index of an existing key.
      Returns:
      Returns the value currently associated with the key.
      See Also:

    • indexReplace

      public VType indexReplace(int index, VType newValue)
      Replaces the value associated with an existing key and returns any previous value stored for that key.
      Specified by:
      indexReplace in interface ShortObjectMap<VType>
      Parameters:
      index - The index of an existing key.
      Returns:
      Returns the previous value associated with the key.
      See Also:

    • indexInsert

      public void indexInsert(int index, short key, VType value)
      Inserts a key-value pair for a key that is not present in the map. This method may help in avoiding double recalculation of the key's hash.
      Specified by:
      indexInsert in interface ShortObjectMap<VType>
      Parameters:
      index - The index of a previously non-existing key, as returned from ShortObjectMap.indexOf(short).
      See Also:

    • indexRemove

      public VType indexRemove(int index)
      Removes a key-value pair at an index previously acquired from ShortObjectMap.indexOf(short).
      Specified by:
      indexRemove in interface ShortObjectMap<VType>
      Parameters:
      index - The index of the key to remove, as returned from ShortObjectMap.indexOf(short).
      Returns:
      Returns the previous value associated with the key.
      See Also:

    • clear

      public void clear()
      Clear all keys and values in the container.
      Specified by:
      clear in interface ShortObjectMap<VType>
      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 ShortObjectMap.clear() should be a better alternative since it'll avoid reallocation.
      Specified by:
      release in interface ShortObjectMap<VType>
      See Also:

    • size

      public int size()
      Specified by:
      size in interface ShortObjectAssociativeContainer<VType>
      Returns:
      Returns the current size (number of assigned keys) in the container.

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface ShortObjectAssociativeContainer<VType>
      Returns:
      Return true if this hash map contains no assigned keys.

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface ShortObjectMap<VType>
      Overrides:
      hashCode in class Object
      Returns:
      A hash code of elements stored in the map. The hash code is defined as a sum of hash codes of keys and values stored within the set). Because sum is commutative, this ensures that different order of elements in a set does not affect the hash code.

    • equals

      public boolean equals(Object obj)
      Compares the specified object with this set for equality. Returns true if and only if the specified object is also a ShortObjectMap and both objects contains exactly the same key-value pairs.
      Specified by:
      equals in interface ShortObjectMap<VType>
      Overrides:
      equals in class Object

    • equalElements

      protected boolean equalElements(ShortObjectHashMap<?> other)
      Return true if all keys of some other container exist in this container. Values are compared using Object.equals(Object) method.

    • ensureCapacity

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

    • 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.

    • iterator

      public Iterator<ShortObjectCursor<VType>> iterator()
      Returns a cursor over the entries (key-value pairs) in this map. The iterator is implemented as a cursor and it returns the same cursor instance on every call to Iterator.next(). To read the current key and value use the cursor's public fields. An example is shown below. 
       for (IntShortCursor c : intShortMap) {
   System.out.println("index=" + c.index + " key=" + c.key + " value=" + c.value);
 }

      The index field inside the cursor gives the internal index inside the container's implementation. The interpretation of this index depends on to the container.

      Specified by:
      iterator in interface Iterable<VType>
      Specified by:
      iterator in interface ShortObjectAssociativeContainer<VType>

    • forEach

      public <T extends ShortObjectProcedure<? super VType>> T forEach(T procedure)
      Applies a given procedure to all keys-value pairs in this container. Returns the argument (any subclass of ShortObjectProcedure. This lets the caller call methods of the argument by chaining the call (even if the argument is an anonymous type) to retrieve computed values.
      Specified by:
      forEach in interface ShortObjectAssociativeContainer<VType>

    • forEach

      public <T extends ShortObjectPredicate<? super VType>> T forEach(T predicate)
      Applies a given predicate to all keys-value pairs in this container. Returns the argument (any subclass of ShortObjectPredicate. This lets the caller call methods of the argument by chaining the call (even if the argument is an anonymous type) to retrieve computed values.

      The iteration is continued as long as the predicate returns true.

      Specified by:
      forEach in interface ShortObjectAssociativeContainer<VType>

    • keys

      public ShortObjectHashMap<VType>.KeysContainer keys()
      Returns a specialized view of the keys of this associated container. The view additionally implements ObjectLookupContainer.
      Specified by:
      keys in interface ShortObjectAssociativeContainer<VType>

    • values

      public ObjectCollection<VType> values()
      Description copied from interface: ShortObjectAssociativeContainer
      Returns a container view of all values present in this container. The returned collection is a view over the key set and any modifications (if allowed) introduced to the collection will propagate to the associative container immediately.
      Specified by:
      values in interface ShortObjectAssociativeContainer<VType>
      Returns:
      Returns a container with all values stored in this map.

    • clone

      public ShortObjectHashMap<VType> clone()
      Overrides:
      clone in class Object

    • toString

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

    • visualizeKeyDistribution

      public String visualizeKeyDistribution(int characters)
      Description copied from interface: ShortObjectMap
      Visually depict the distribution of keys.
      Specified by:
      visualizeKeyDistribution in interface ShortObjectMap<VType>
      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.

    • from

      public static <VType> ShortObjectHashMap<VType> from(short[] keys, VType[] values)
      Creates a hash map from two index-aligned arrays of key-value pairs.

    • hashKey

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

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

    • 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(short[] fromKeys, VType[] fromValues)
      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, short pendingKey, VType pendingValue)
      This method is invoked when there is a new key/ value pair to be inserted into the buffers 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 and values allocated to (and including) slot.