Package gnu.trove

Class TObjectHash<T>

java.lang.Object
gnu.trove.THash
gnu.trove.TObjectHash<T>
All Implemented Interfaces:
TObjectHashingStrategy<T>, Externalizable, Serializable, Cloneable
Direct Known Subclasses:
THashMap, THashSet, TObjectByteHashMap, TObjectDoubleHashMap, TObjectFloatHashMap, TObjectIntHashMap, TObjectLongHashMap, TObjectShortHashMap
public abstract class TObjectHash<T> extends THash implements TObjectHashingStrategy<T>
An open addressed hashing implementation for Object types. Created: Sun Nov 4 08:56:06 2001
Version:
$Id: TObjectHash.java,v 1.27 2009/06/01 22:14:44 robeden Exp $
Author:
Eric D. Friedman
See Also:

  • Field Details

    • _set

      protected transient Object[] _set
      the set of Objects

    • _hashingStrategy

      protected TObjectHashingStrategy<T> _hashingStrategy
      the strategy used to hash objects in this collection.

    • REMOVED

      protected static final Object REMOVED

    • FREE

      protected static final Object FREE

  • Constructor Details

    • TObjectHash

      public TObjectHash()
      Creates a new TObjectHash instance with the default capacity and load factor.

    • TObjectHash

      public TObjectHash(TObjectHashingStrategy<T> strategy)
      Creates a new TObjectHash instance with the default capacity and load factor and a custom hashing strategy.
      Parameters:
      strategy - used to compute hash codes and to compare objects.

    • TObjectHash

      public TObjectHash(int initialCapacity)
      Creates a new TObjectHash instance whose capacity is the next highest prime above initialCapacity + 1 unless that value is already prime.
      Parameters:
      initialCapacity - an int value

    • TObjectHash

      public TObjectHash(int initialCapacity, TObjectHashingStrategy<T> strategy)
      Creates a new TObjectHash instance whose capacity is the next highest prime above initialCapacity + 1 unless that value is already prime. Uses the specified custom hashing strategy.
      Parameters:
      initialCapacity - an int value
      strategy - used to compute hash codes and to compare objects.

    • TObjectHash

      public TObjectHash(int initialCapacity, float loadFactor)
      Creates a new TObjectHash instance with a prime value at or near the specified capacity and load factor.
      Parameters:
      initialCapacity - used to find a prime capacity for the table.
      loadFactor - used to calculate the threshold over which rehashing takes place.

    • TObjectHash

      public TObjectHash(int initialCapacity, float loadFactor, TObjectHashingStrategy<T> strategy)
      Creates a new TObjectHash instance with a prime value at or near the specified capacity and load factor. Uses the specified custom hashing strategy.
      Parameters:
      initialCapacity - used to find a prime capacity for the table.
      loadFactor - used to calculate the threshold over which rehashing takes place.
      strategy - used to compute hash codes and to compare objects.

  • Method Details

    • clone

      public TObjectHash<T> clone()
      Overrides:
      clone in class THash
      Returns:
      a shallow clone of this collection

    • capacity

      protected int capacity()
      Specified by:
      capacity in class THash
      Returns:
      the current physical capacity of the hash table.

    • removeAt

      protected void removeAt(int index)
      Description copied from class: THash
      Delete the record at index. Reduces the size of the collection by one.
      Overrides:
      removeAt in class THash
      Parameters:
      index - an int value

    • setUp

      protected int setUp(int initialCapacity)
      initializes the Object set of this hash table.
      Overrides:
      setUp in class THash
      Parameters:
      initialCapacity - an int value
      Returns:
      an int value

    • forEach

      public boolean forEach(TObjectProcedure<T> procedure)
      Executes procedure for each element in the set.
      Parameters:
      procedure - a TObjectProcedure value
      Returns:
      false if the loop over the set terminated because the procedure returned false for some value.

    • contains

      public boolean contains(Object obj)
      Searches the set for obj
      Parameters:
      obj - an Object value
      Returns:
      a boolean value

    • index

      protected int index(T obj)
      Locates the index of obj.
      Parameters:
      obj - an Object value
      Returns:
      the index of obj or -1 if it isn't in the set.

    • insertionIndex

      protected int insertionIndex(T obj)
      Locates the index at which obj can be inserted. if there is already a value equal()ing obj in the set, returns that value's index as -index - 1.
      Parameters:
      obj - an Object value
      Returns:
      the index of a FREE slot at which obj can be inserted or, if obj is already stored in the hash, the negative value of that index, minus 1: -index -1.

    • computeHashCode

      public final int computeHashCode(T o)
      This is the default implementation of TObjectHashingStrategy: it delegates hashing to the Object's hashCode method.
      Specified by:
      computeHashCode in interface TObjectHashingStrategy<T>
      Parameters:
      o - for which the hashcode is to be computed
      Returns:
      the hashCode
      See Also:

    • equals

      public final boolean equals(T o1, T o2)
      This is the default implementation of TObjectHashingStrategy: it delegates equality comparisons to the first parameter's equals() method.
      Specified by:
      equals in interface TObjectHashingStrategy<T>
      Parameters:
      o1 - an Object value
      o2 - an Object value
      Returns:
      true if the objects are equal
      See Also:

    • throwObjectContractViolation

      protected final void throwObjectContractViolation(Object o1, Object o2) throws IllegalArgumentException
      Convenience methods for subclasses to use in throwing exceptions about badly behaved user objects employed as keys. We have to throw an IllegalArgumentException with a rather verbose message telling the user that they need to fix their object implementation to conform to the general contract for java.lang.Object.
      Parameters:
      o1 - the first of the equal elements with unequal hash codes.
      o2 - the second of the equal elements with unequal hash codes.
      Throws:
      IllegalArgumentException - the whole point of this method.

    • writeExternal

      public void writeExternal(ObjectOutput out) throws IOException
      Specified by:
      writeExternal in interface Externalizable
      Overrides:
      writeExternal in class THash
      Throws:
      IOException

    • readExternal

      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      Specified by:
      readExternal in interface Externalizable
      Overrides:
      readExternal in class THash
      Throws:
      IOException
      ClassNotFoundException