LongKeyHashMap

java.lang.Object
- fabric.common.util.AbstractLongKeyMap<V>
- - fabric.common.util.LongKeyHashMap<V>

All Implemented Interfaces:

LongKeyMap<V>, java.io.Serializable, java.lang.Cloneable
```
public class LongKeyHashMap<V>
extends AbstractLongKeyMap<V>
implements LongKeyMap<V>, java.lang.Cloneable, java.io.Serializable
```
This class provides a hashtable-backed implementation of the Map interface.
It uses a hash-bucket approach; that is, hash collisions are handled by linking the new node off of the pre-existing node (or list of nodes). In this manner, techniques such as linear probing (which can cause primary clustering) and rehashing (which does not fit very well with Java's method of precomputing hash codes) are avoided.
Under ideal circumstances (no collisions), HashMap offers O(1) performance on most operations (containsValue() is, of course, O(n)). In the worst case (all keys map to the same hash code -- very unlikely), most operations are O(n).
HashMap is part of the JDK1.2 Collections API. It differs from Hashtable in that it accepts the null key and null values, and it does not support "Enumeration views." Also, it is not synchronized; if you plan to use it in multiple threads, consider using:
Map m = Collections.synchronizedMap(new HashMap(...));
The iterators are fail-fast, meaning that any structural modification, except for remove() called on the iterator itself, cause the iterator to throw a ConcurrentModificationException rather than exhibit non-deterministic behavior.

Since:

1.2

Author:

Jon Zeppieri, Jochen Hoenicke, Bryce McKinlay, Eric Blake (ebb9@email.byu.edu)

See Also:

LongCollection, LongKeyMap, Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class fabric.common.util.AbstractLongKeyMap
  AbstractLongKeyMap.SimpleEntry<V>, AbstractLongKeyMap.SimpleImmutableEntry<V>
- Nested classes/interfaces inherited from interface fabric.common.util.LongKeyMap
  LongKeyMap.Entry<V>

Constructor Summary

Constructors
Constructor and Description
`LongKeyHashMap()` Construct a new HashMap with the default capacity (11) and the default load factor (1).
`LongKeyHashMap(int initialCapacity)` Construct a new HashMap with a specific inital capacity and default load factor of 1.
`LongKeyHashMap(int initialCapacity, float loadFactor)` Construct a new HashMap with a specific inital capacity and load factor.
`LongKeyHashMap(LongKeyMap<? extends V> m)` Construct a new HashMap from the given Map, with initial capacity the greater of the size of `m` or the default of 11.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Clears the Map so it has no keys.
`java.lang.Object`	`clone()` Returns a shallow clone of this HashMap.
`boolean`	`containsKey(long key)` Returns true if the supplied object `equals()` a key in this HashMap.
`boolean`	`containsValue(java.lang.Object value)` Returns true if this HashMap contains a value `o`, such that `o.equals(value)`.
`java.util.Set<LongKeyMap.Entry<V>>`	`entrySet()` Returns a "set view" of this HashMap's entries.
`V`	`get(long key)` Return the value in this HashMap associated with the supplied key, or `null` if the key maps to nothing.
`boolean`	`isEmpty()` Returns true if there are no key-value mappings currently in this Map.
`LongSet`	`keySet()` Returns a "set view" of this HashMap's keys.
`V`	`put(long key, V value)` Puts the supplied value into the Map, mapped by the supplied key.
`<T extends V> void`	`putAll(LongKeyMap<T> m)` Copies all elements of the given map into this hashtable.
`V`	`remove(long key)` Removes from the HashMap and returns the value which is mapped by the supplied key.
`int`	`size()` Returns the number of kay-value mappings currently in this Map.
`java.util.Collection<V>`	`values()` Returns a "collection view" (or "bag view") of this HashMap's values.

Methods inherited from class fabric.common.util.AbstractLongKeyMap
equals, hashCode, toString

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface fabric.common.util.LongKeyMap
equals, hashCode

- Constructor Detail
  - LongKeyHashMap
```
public LongKeyHashMap()
```
    Construct a new HashMap with the default capacity (11) and the default load factor (1).
  - LongKeyHashMap
```
public LongKeyHashMap(LongKeyMap<? extends V> m)
```
    Construct a new HashMap from the given Map, with initial capacity the greater of the size of m or the default of 11.
    Every element in Map m will be put into this new HashMap.
    
    Parameters:
    
    m - a Map whose key / value pairs will be put into the new HashMap. NOTE: key / value pairs are not cloned in this constructor.
    
    Throws:
    
    java.lang.NullPointerException - if m is null
  - LongKeyHashMap
```
public LongKeyHashMap(int initialCapacity)
```
    Construct a new HashMap with a specific inital capacity and default load factor of 1.
    
    Parameters:
    
    initialCapacity - the initial capacity of this HashMap (>=0)
    
    Throws:
    
    java.lang.IllegalArgumentException - if (initialCapacity < 0)
  - LongKeyHashMap
```
public LongKeyHashMap(int initialCapacity,
                      float loadFactor)
```
    Construct a new HashMap with a specific inital capacity and load factor.
    
    Parameters:
    
    initialCapacity - the initial capacity (>=0)
    
    loadFactor - the load factor (> 0, not NaN)
    
    Throws:
    
    java.lang.IllegalArgumentException - if (initialCapacity < 0) || ! (loadFactor > 0.0)
- Method Detail
  - size
```
public int size()
```
    Returns the number of kay-value mappings currently in this Map.
    
    Specified by:
    
    size in interface LongKeyMap<V>
    
    Overrides:
    
    size in class AbstractLongKeyMap<V>
    
    Returns:
    
    the size
    
    See Also:
    
    Set.size()
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if there are no key-value mappings currently in this Map.
    
    Specified by:
    
    isEmpty in interface LongKeyMap<V>
    
    Overrides:
    
    isEmpty in class AbstractLongKeyMap<V>
    
    Returns:
    
    size() == 0
    
    See Also:
    
    AbstractLongKeyMap.size()
  - get
```
public V get(long key)
```
    Return the value in this HashMap associated with the supplied key, or null if the key maps to nothing. NOTE: Since the value could also be null, you must use containsKey to see if this key actually maps to something.
    
    Specified by:
    
    get in interface LongKeyMap<V>
    
    Overrides:
    
    get in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - the key for which to fetch an associated value
    
    Returns:
    
    what the key maps to, if present
    
    See Also:
    
    put(long, Object), containsKey(long)
  - containsKey
```
public boolean containsKey(long key)
```
    Returns true if the supplied object equals() a key in this HashMap.
    
    Specified by:
    
    containsKey in interface LongKeyMap<V>
    
    Overrides:
    
    containsKey in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - the key to search for in this HashMap
    
    Returns:
    
    true if the key is in the table
    
    See Also:
    
    containsValue(Object)
  - put
```
public V put(long key,
             V value)
```
    Puts the supplied value into the Map, mapped by the supplied key. The value may be retrieved by any object which equals() this key. NOTE: Since the prior value could also be null, you must first use containsKey if you want to see if you are replacing the key's mapping.
    
    Specified by:
    
    put in interface LongKeyMap<V>
    
    Overrides:
    
    put in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - the key used to locate the value
    
    value - the value to be stored in the HashMap
    
    Returns:
    
    the prior mapping of the key, or null if there was none
    
    See Also:
    
    get(long)
  - putAll
```
public <T extends V> void putAll(LongKeyMap<T> m)
```
    Copies all elements of the given map into this hashtable. If this table already has a mapping for a key, the new mapping replaces the current one.
    
    Specified by:
    
    putAll in interface LongKeyMap<V>
    
    Overrides:
    
    putAll in class AbstractLongKeyMap<V>
    
    Parameters:
    
    m - the map to be hashed into this
    
    See Also:
    
    AbstractLongKeyMap.put(long, Object)
  - remove
```
public V remove(long key)
```
    Removes from the HashMap and returns the value which is mapped by the supplied key. If the key maps to nothing, then the HashMap remains unchanged, and null is returned. NOTE: Since the value could also be null, you must use containsKey to see if you are actually removing a mapping.
    
    Specified by:
    
    remove in interface LongKeyMap<V>
    
    Overrides:
    
    remove in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - the key used to locate the value to remove
    
    Returns:
    
    whatever the key mapped to, if present
    
    See Also:
    
    Iterator.remove()
  - clear
```
public void clear()
```
    Clears the Map so it has no keys. This is O(1).
    
    Specified by:
    
    clear in interface LongKeyMap<V>
    
    Overrides:
    
    clear in class AbstractLongKeyMap<V>
    
    See Also:
    
    LongSet.clear()
  - containsValue
```
public boolean containsValue(java.lang.Object value)
```
    Returns true if this HashMap contains a value o, such that o.equals(value).
    
    Specified by:
    
    containsValue in interface LongKeyMap<V>
    
    Overrides:
    
    containsValue in class AbstractLongKeyMap<V>
    
    Parameters:
    
    value - the value to search for in this HashMap
    
    Returns:
    
    true if at least one key maps to the value
    
    See Also:
    
    containsKey(long)
  - clone
```
public java.lang.Object clone()
```
    Returns a shallow clone of this HashMap. The Map itself is cloned, but its contents are not. This is O(n).
    
    Overrides:
    
    clone in class AbstractLongKeyMap<V>
    
    Returns:
    
    the clone
    
    See Also:
    
    Cloneable, Object.clone()
  - keySet
```
public LongSet keySet()
```
    Returns a "set view" of this HashMap's keys. The set is backed by the HashMap, so changes in one show up in the other. The set supports element removal, but not element addition.
    
    Specified by:
    
    keySet in interface LongKeyMap<V>
    
    Overrides:
    
    keySet in class AbstractLongKeyMap<V>
    
    Returns:
    
    a set view of the keys
    
    See Also:
    
    values(), entrySet()
  - values
```
public java.util.Collection<V> values()
```
    Returns a "collection view" (or "bag view") of this HashMap's values. The collection is backed by the HashMap, so changes in one show up in the other. The collection supports element removal, but not element addition.
    
    Specified by:
    
    values in interface LongKeyMap<V>
    
    Overrides:
    
    values in class AbstractLongKeyMap<V>
    
    Returns:
    
    a bag view of the values
    
    See Also:
    
    keySet(), entrySet()
  - entrySet
```
public java.util.Set<LongKeyMap.Entry<V>> entrySet()
```
    Returns a "set view" of this HashMap's entries. The set is backed by the HashMap, so changes in one show up in the other. The set supports element removal, but not element addition.
    Note that the iterators for all three views, from keySet(), entrySet(), and values(), traverse the HashMap in the same sequence.
    
    Specified by:
    
    entrySet in interface LongKeyMap<V>
    
    Specified by:
    
    entrySet in class AbstractLongKeyMap<V>
    
    Returns:
    
    a set view of the entries
    
    See Also:
    
    keySet(), values(), LongKeyMap.Entry

Class LongKeyHashMap<V>

Nested Class Summary

Nested classes/interfaces inherited from class fabric.common.util.AbstractLongKeyMap

Nested classes/interfaces inherited from interface fabric.common.util.LongKeyMap

Constructor Summary

Method Summary

Methods inherited from class fabric.common.util.AbstractLongKeyMap

Methods inherited from class java.lang.Object

Methods inherited from interface fabric.common.util.LongKeyMap

Constructor Detail

LongKeyHashMap

LongKeyHashMap

LongKeyHashMap

LongKeyHashMap

Method Detail

size

isEmpty

get

containsKey

put

putAll

remove

clear

containsValue

clone

keySet

values

entrySet