Package com.carrotsearch.hppc

Class CharIntWormMap

  • All Implemented Interfaces:
    Accountable, CharIntAssociativeContainer, CharIntMap, Preallocable, java.lang.Cloneable, java.lang.Iterable<CharIntCursor>
    @Generated(date="2021-06-08T13:12:54+0200",
           value="KTypeVTypeWormMap.java")
public class CharIntWormMap
extends java.lang.Object
implements CharIntMap, Preallocable, java.lang.Cloneable, Accountable
    A hash map of char to int, implemented using Worm Hashing strategy.

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

    See Also:
    HPPC interfaces diagram

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      class  CharIntWormMap.KeysContainer
      A view of the keys inside this map.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected int iterationSeed
      Seed used to ensure the hash iteration order is different from an iteration to another.
      char[] keys
      The array holding keys.
      byte[] next
      abs(next[i])=offset to next chained entry index.
      protected int size
      Map size (number of entries).
      int[] values
      The array holding values.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int addTo​(char key, int additionValue)
      An equivalent of calling
      protected void allocateBuffers​(int capacity)  
      void clear()
      Clear all keys and values in the container.
      CharIntWormMap clone()
      Clones this map.
      boolean containsKey​(char key)
      Returns true if this container has an association to a value for the given key.
      void ensureCapacity​(int expectedElements)
      Ensure this container can hold at least the given number of elements without resizing its buffers.
      boolean equals​(java.lang.Object o)
      Compares the specified object with this set for equality.
      <T extends CharIntProcedure>
      T      		 forEach​(T procedure)
      Applies a given procedure to all keys-value pairs in this container.
      static CharIntWormMap from​(char[] keys, int[] values)
      Creates a new instance from two index-aligned arrays of key-value pairs.
      int get​(char key)
      int getOrDefault​(char key, int defaultValue)
      int hashCode()
      protected int hashKey​(char key)  
      boolean indexExists​(int index)
      int indexGet​(int index)
      Returns the value associated with an existing key.
      void indexInsert​(int index, char key, int value)
      Inserts a key-value pair for a key that is not present in the map.
      int indexOf​(char 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).
      int indexRemove​(int index)
      Removes a key-value pair at an index previously acquired from CharIntMap.indexOf(char).
      int indexReplace​(int index, int newValue)
      Replaces the value associated with an existing key and returns any previous value stored for that key.
      boolean isEmpty()
      java.util.Iterator<CharIntCursor> iterator()
      Returns a cursor over the entries (key-value pairs) in this map.
      CharIntWormMap.KeysContainer keys()
      Returns a collection of keys of this container.
      protected int nextIterationSeed()
      Provides the next iteration seed used to build the iteration starting slot and offset increment.
      int noValue()
      The value returned when there is no value associated to a key in this map.
      int put​(char key, int value)
      Place a given key and value in the container.
      int putAll​(CharIntAssociativeContainer container)
      Puts all keys from another container to this map, replacing the values of existing keys, if such keys are present.
      int putAll​(java.lang.Iterable<? extends CharIntCursor> iterable)
      Puts all keys from an iterable cursor to this map, replacing the values of existing keys, if such keys are present.
      boolean putIfAbsent​(char key, int value)  
      int putOrAdd​(char key, int putValue, int incrementValue)
      If key exists, putValue is inserted into the map, otherwise any existing value is incremented by additionValue.
      long ramBytesAllocated()
      Allocated memory estimation
      long ramBytesUsed()
      Bytes that is actually been used
      void release()
      Removes all elements from the collection and additionally releases any internal buffers.
      int remove​(char key)
      Remove all values at the given key.
      int removeAll​(CharContainer other)
      Removes all keys (and associated values) present in a given container.
      int removeAll​(CharIntPredicate predicate)
      Removes all keys (and associated values) for which the predicate returns true.
      int removeAll​(CharPredicate predicate)
      Removes all keys (and associated values) for which the predicate returns true.
      int size()
      java.lang.String toString()
      IntCollection values()
      Returns a container view of all values present in this container.
      java.lang.String visualizeKeyDistribution​(int characters)
      Visually depict the distribution of keys.

      • Methods inherited from class java.lang.Object

        finalize, getClass, notify, notifyAll, wait, wait, wait

      • Methods inherited from interface java.lang.Iterable

        forEach, spliterator

    • Field Detail

      • keys

        public char[] keys
        The array holding keys.

      • values

        public int[] values
        The array holding values.

      • 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
        Map size (number of entries).

      • iterationSeed

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

    • Constructor Detail

      • CharIntWormMap

        public CharIntWormMap()
        New instance with sane defaults.

      • CharIntWormMap

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

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

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

      • CharIntWormMap

        public CharIntWormMap​(CharIntAssociativeContainer container)
        Creates a new instance from all key-value pairs of another container.

    • Method Detail

      • from

        public static CharIntWormMap from​(char[] keys,
                                  int[] values)
        Creates a new instance from two index-aligned arrays of key-value pairs.

      • clone

        public CharIntWormMap clone()
        Clones this map. The cloning operation is efficient because it copies directly the internal arrays, without having to put entries in the cloned map. The cloned map has the same entries and the same capacity as this map.
        Overrides:
        clone in class java.lang.Object
        Returns:
        A shallow copy of this map.

      • noValue

        public int noValue()
        The value returned when there is no value associated to a key in this map. This method can be extended to change it.

      • size

        public int size()
        Specified by:
        size in interface CharIntAssociativeContainer
        Returns:
        Returns the current size (number of assigned keys) in the container.

      • get

        public int get​(char key)
        Specified by:
        get in interface CharIntMap
        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 int getOrDefault​(char key,
                        int defaultValue)
        Specified by:
        getOrDefault in interface CharIntMap
        Returns:
        Returns the value associated with the given key or the provided default value if the key is not associated with any value.

      • put

        public int put​(char key,
               int value)
        Place a given key and value in the container.
        Specified by:
        put in interface CharIntMap
        Returns:
        The value previously stored under the given key in the map is returned.

      • putAll

        public int putAll​(CharIntAssociativeContainer 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 CharIntMap
        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​(java.lang.Iterable<? extends CharIntCursor> iterable)
        Puts all keys from an iterable cursor to this map, replacing the values of existing keys, if such keys are present.
        Specified by:
        putAll in interface CharIntMap
        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.

      • putOrAdd

        public int putOrAdd​(char key,
                    int putValue,
                    int incrementValue)
        If key exists, putValue is inserted into the map, otherwise any existing value is incremented by additionValue.
        Specified by:
        putOrAdd in interface CharIntMap
        Parameters:
        key - The key of the value to adjust.
        putValue - The value to put if key does not exist.
        incrementValue - The value to add to the existing value if key exists.
        Returns:
        Returns the current value associated with key (after changes).

      • addTo

        public int addTo​(char key,
                 int additionValue)
        An equivalent of calling 
         putOrAdd(key, additionValue, additionValue);
        Specified by:
        addTo in interface CharIntMap
        Parameters:
        key - The key of the value to adjust.
        additionValue - The value to put or add to the existing value if key exists.
        Returns:
        Returns the current value associated with key (after changes).

      • putIfAbsent

        public boolean putIfAbsent​(char key,
                           int value)
        Parameters:
        key - The key of the value to check.
        value - The value to put if key does not exist.
        Returns:
        true if key did not exist and value was placed in the map.

      • remove

        public int remove​(char 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 CharIntMap

      • removeAll

        public int removeAll​(CharContainer 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 CharIntAssociativeContainer
        Returns:
        Returns the number of elements actually removed as a result of this call.

      • removeAll

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

      • removeAll

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

      • forEach

        public <T extends CharIntProcedure> T forEach​(T procedure)
        Applies a given procedure to all keys-value pairs in this container. Returns the argument (any subclass of CharIntProcedure. 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.
        Specified by:
        forEach in interface CharIntAssociativeContainer

      • forEach

        public <T extends CharIntPredicate> T forEach​(T predicate)
        Applies a given predicate to all keys-value pairs in this container. Returns the argument (any subclass of CharIntPredicate. 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. The iteration is continued as long as the predicate returns true.
        Specified by:
        forEach in interface CharIntAssociativeContainer

      • keys

        public CharIntWormMap.KeysContainer keys()
        Returns a collection of keys of 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:
        keys in interface CharIntAssociativeContainer

      • values

        public IntCollection values()
        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 CharIntAssociativeContainer

      • iterator

        public java.util.Iterator<CharIntCursor> 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 CharIntAssociativeContainer
        Specified by:
        iterator in interface java.lang.Iterable<CharIntCursor>

      • containsKey

        public boolean containsKey​(char key)
        Returns true if this container has an association to a value for the given key.
        Specified by:
        containsKey in interface CharIntAssociativeContainer

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

      • equals

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

      • hashCode

        public int hashCode()
        Specified by:
        hashCode in interface CharIntMap
        Overrides:
        hashCode in class java.lang.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.

      • hashKey

        protected int hashKey​(char key)

      • indexOf

        public int indexOf​(char 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 CharIntMap
        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:
        CharIntMap.indexExists(int), CharIntMap.indexGet(int), CharIntMap.indexInsert(int, char, int), CharIntMap.indexReplace(int, int)

      • indexExists

        public boolean indexExists​(int index)
        Specified by:
        indexExists in interface CharIntMap
        Parameters:
        index - The index of a given key, as returned from CharIntMap.indexOf(char).
        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:
        CharIntMap.indexOf(char)

      • indexGet

        public int indexGet​(int index)
        Returns the value associated with an existing key.
        Specified by:
        indexGet in interface CharIntMap
        Parameters:
        index - The index of an existing key.
        Returns:
        Returns the value currently associated with the key.
        See Also:
        CharIntMap.indexOf(char)

      • indexReplace

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

      • indexInsert

        public void indexInsert​(int index,
                        char key,
                        int 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 CharIntMap
        Parameters:
        index - The index of a previously non-existing key, as returned from CharIntMap.indexOf(char).
        See Also:
        CharIntMap.indexOf(char)

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • 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 java.lang.String visualizeKeyDistribution​(int characters)
        Visually depict the distribution of keys.
        Specified by:
        visualizeKeyDistribution in interface CharIntMap
        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.