AbstractHashMap

java.lang.Object
- prefuse.util.collections.AbstractHashMap

Direct Known Subclasses:

IntObjectHashMap
```
public abstract class AbstractHashMap
extends java.lang.Object
```
Abstract base class for hash maps holding objects or primitive data types such as int, float, etc. as keys and/or values. First see the package summary and javadoc tree view to get the broad picture.
Note that implementations are not synchronized.

See Also:

HashMap

Field Summary

Fields
Modifier and Type	Field and Description
`protected static int`	`defaultCapacity`
`protected static double`	`defaultMaxLoadFactor`
`protected static double`	`defaultMinLoadFactor`
`protected int`	`distinct` The number of distinct associations in the map; its "size()".
`protected int`	`highWaterMark`
`protected int`	`lowWaterMark` The table capacity c=table.length always satisfies the invariant `c * minLoadFactor <= s <= c * maxLoadFactor`, where s=size() is the number of associations currently contained.
`protected double`	`maxLoadFactor` The maximum load factor for the hash-table.
`protected double`	`minLoadFactor` The minimum load factor for the hash-table.

Constructor Summary

Constructors
Modifier Constructor and Description

protected AbstractHashMap()
Makes this class non instantiable, but still let's others inherit from it.

Constructors
Modifier	Constructor and Description
`protected`	`AbstractHashMap()` Makes this class non instantiable, but still let's others inherit from it.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`protected int`	`chooseGrowCapacity(int size, double minLoad, double maxLoad)` Chooses a new prime table capacity optimized for growing that (approximately) satisfies the invariant `c * minLoadFactor <= size <= c * maxLoadFactor` and has at least one FREE slot for the given size.
`protected int`	`chooseHighWaterMark(int capacity, double maxLoad)` Returns new high water mark threshold based on current capacity and maxLoadFactor.
`protected int`	`chooseLowWaterMark(int capacity, double minLoad)` Returns new low water mark threshold based on current capacity and minLoadFactor.
`protected int`	`chooseMeanCapacity(int size, double minLoad, double maxLoad)` Chooses a new prime table capacity neither favoring shrinking nor growing, that (approximately) satisfies the invariant `c * minLoadFactor <= size <= c * maxLoadFactor` and has at least one FREE slot for the given size.
`protected int`	`chooseShrinkCapacity(int size, double minLoad, double maxLoad)` Chooses a new prime table capacity optimized for shrinking that (approximately) satisfies the invariant `c * minLoadFactor <= size <= c * maxLoadFactor` and has at least one FREE slot for the given size.
`abstract void`	`clear()` Removes all (key,value) associations from the receiver.
`void`	`ensureCapacity(int minCapacity)` Ensures that the receiver can hold at least the specified number of elements without needing to allocate new internal memory.
`boolean`	`isEmpty()` Returns `true` if the receiver contains no (key,value) associations.
`protected int`	`nextPrime(int desiredCapacity)` Returns a prime number which is `>= desiredCapacity` and very close to `desiredCapacity` (within 11% if `desiredCapacity >= 1000`).
`protected void`	`setUp(int initialCapacity, double minLoadFactor, double maxLoadFactor)` Initializes the receiver.
`int`	`size()` Returns the number of (key,value) associations currently contained.
`void`	`trimToSize()` Trims the capacity of the receiver to be the receiver's current size.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - distinct
```
protected int distinct
```
    The number of distinct associations in the map; its "size()".
  - lowWaterMark
```
protected int lowWaterMark
```
    The table capacity c=table.length always satisfies the invariant c * minLoadFactor <= s <= c * maxLoadFactor, where s=size() is the number of associations currently contained. The term "c * minLoadFactor" is called the "lowWaterMark", "c * maxLoadFactor" is called the "highWaterMark". In other words, the table capacity (and proportionally the memory used by this class) oscillates within these constraints. The terms are precomputed and cached to avoid recalculating them each time put(..) or removeKey(...) is called.
  - highWaterMark
```
protected int highWaterMark
```
  - minLoadFactor
```
protected double minLoadFactor
```
    The minimum load factor for the hash-table.
  - maxLoadFactor
```
protected double maxLoadFactor
```
    The maximum load factor for the hash-table.
  - defaultCapacity
```
protected static final int defaultCapacity
```
    See Also:
    
    Constant Field Values
  - defaultMinLoadFactor
```
protected static final double defaultMinLoadFactor
```
    See Also:
    
    Constant Field Values
  - defaultMaxLoadFactor
```
protected static final double defaultMaxLoadFactor
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - AbstractHashMap
```
protected AbstractHashMap()
```
    Makes this class non instantiable, but still let's others inherit from it.
- Method Detail
  - chooseGrowCapacity
```
protected int chooseGrowCapacity(int size,
                                 double minLoad,
                                 double maxLoad)
```
    Chooses a new prime table capacity optimized for growing that (approximately) satisfies the invariant c * minLoadFactor <= size <= c * maxLoadFactor and has at least one FREE slot for the given size.
  - chooseHighWaterMark
```
protected int chooseHighWaterMark(int capacity,
                                  double maxLoad)
```
    Returns new high water mark threshold based on current capacity and maxLoadFactor.
    
    Returns:
    
    int the new threshold.
  - chooseLowWaterMark
```
protected int chooseLowWaterMark(int capacity,
                                 double minLoad)
```
    Returns new low water mark threshold based on current capacity and minLoadFactor.
    
    Returns:
    
    int the new threshold.
  - chooseMeanCapacity
```
protected int chooseMeanCapacity(int size,
                                 double minLoad,
                                 double maxLoad)
```
    Chooses a new prime table capacity neither favoring shrinking nor growing, that (approximately) satisfies the invariant c * minLoadFactor <= size <= c * maxLoadFactor and has at least one FREE slot for the given size.
  - chooseShrinkCapacity
```
protected int chooseShrinkCapacity(int size,
                                   double minLoad,
                                   double maxLoad)
```
    Chooses a new prime table capacity optimized for shrinking that (approximately) satisfies the invariant c * minLoadFactor <= size <= c * maxLoadFactor and has at least one FREE slot for the given size.
  - clear
```
public abstract void clear()
```
    Removes all (key,value) associations from the receiver.
  - ensureCapacity
```
public void ensureCapacity(int minCapacity)
```
    Ensures that the receiver can hold at least the specified number of elements without needing to allocate new internal memory. If necessary, allocates new internal memory and increases the capacity of the receiver.
    This method never need be called; it is for performance tuning only. Calling this method before put()ing a large number of associations boosts performance, because the receiver will grow only once instead of potentially many times.
    This default implementation does nothing. Override this method if necessary.
    
    Parameters:
    
    minCapacity - the desired minimum capacity.
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if the receiver contains no (key,value) associations.
    
    Returns:
    
    true if the receiver contains no (key,value) associations.
  - nextPrime
```
protected int nextPrime(int desiredCapacity)
```
    Returns a prime number which is >= desiredCapacity and very close to desiredCapacity (within 11% if desiredCapacity >= 1000).
    
    Parameters:
    
    desiredCapacity - the capacity desired by the user.
    
    Returns:
    
    the capacity which should be used for a hash-table.
  - setUp
```
protected void setUp(int initialCapacity,
                     double minLoadFactor,
                     double maxLoadFactor)
```
    Initializes the receiver. You will almost certainly need to override this method in subclasses to initialize the hash table.
    
    Parameters:
    
    initialCapacity - the initial capacity of the receiver.
    
    minLoadFactor - the minLoadFactor of the receiver.
    
    maxLoadFactor - the maxLoadFactor of the receiver.
    
    Throws:
    
    java.lang.IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor).
  - size
```
public int size()
```
    Returns the number of (key,value) associations currently contained.
    
    Returns:
    
    the number of (key,value) associations currently contained.
  - trimToSize
```
public void trimToSize()
```
    Trims the capacity of the receiver to be the receiver's current size. Releases any superfluous internal memory. An application can use this operation to minimize the storage of the receiver.
    This default implementation does nothing. Override this method if necessary.

Class AbstractHashMap

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

distinct

lowWaterMark

highWaterMark

minLoadFactor

maxLoadFactor

defaultCapacity

defaultMinLoadFactor

defaultMaxLoadFactor

Constructor Detail

AbstractHashMap

Method Detail

chooseGrowCapacity

chooseHighWaterMark

chooseLowWaterMark

chooseMeanCapacity

chooseShrinkCapacity

clear

ensureCapacity

isEmpty

nextPrime

setUp

size

trimToSize