HashMap

java.lang.Object
- de.uni_hildesheim.sse.monitoring.runtime.utils.HashMap<K,V>

Type Parameters:

K - the key type

V - the value type

Direct Known Subclasses:

AnnotationBuilderMap
```
public class HashMap<K,V>
extends java.lang.Object
```
Reimplements a simple version of the hashmap java.util.HashMap in order to release dependencies during instrumentation.

Since:

1.00

Version:

1.00

Author:

from SUN/ORACLE

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`HashMap.Entry<K,V>` Implements a bucket entry.
`private class`	`HashMap.KeyIterator<I>` A specific iterator for the keys.
`private class`	`HashMap.MapIterator<I>` Implements a generic iterator.

Field Summary

Fields
Modifier and Type	Field and Description
`private static int`	`DEFAULT_INITIAL_CAPACITY` The default initial capacity - MUST be a power of two.
`private static float`	`DEFAULT_LOAD_FACTOR` The load factor used when none specified in constructor.
`private int`	`keySize` The number of keys contained in this map.
`private float`	`loadFactor` The load factor for the hash table.
`private static int`	`MAXIMUM_CAPACITY` The maximum capacity, used if a higher value is implicitly specified by either of the constructors with arguments.
`private int`	`size` The number of key-value mappings contained in this map.
`private HashMap.Entry[]`	`table` The table, resized as necessary.
`private int`	`threshold` The next size value at which to resize (capacity * load factor).

Constructor Summary

Constructors
Constructor and Description
`HashMap()` Constructs an empty `HashMap` with the default initial capacity (16) and the default load factor (0.75).
`HashMap(int initialCapacity)` Constructs an empty `HashMap` with the specified initial capacity and the default load factor (0.75).
`HashMap(int initialCapacity, float loadFactor)` Constructs an empty `HashMap` with the specified initial capacity and load factor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) void`	`addEntry(int hash, K key, V value, int bucketIndex)` Adds a new entry with the specified key, value and hash code to the specified bucket.
`void`	`clear()` Removes all of the mappings from this map.
`boolean`	`containsKey(java.lang.Object key)` Returns `true` if this map contains a mapping for the specified key.
`java.lang.Iterable<HashMap.Entry<K,V>>`	`entries()` Returns an iterator over the entries stored in this map.
`V`	`get(java.lang.Object key)` Returns the value to which the specified key is mapped, or `null` if this map contains no mapping for the key.
`(package private) HashMap.Entry<K,V>`	`getEntry(java.lang.Object key)` Returns the entry associated with the specified key in the HashMap.
`private V`	`getForNullKey()` Offloaded version of get() to look up null keys.
`(package private) static int`	`hash(int key)` Applies a supplemental hash function to a given hashCode, which defends against poor quality hash functions.
`(package private) static int`	`indexFor(int hash, int length)` Returns index for hash code h.
`boolean`	`isEmpty()` Returns `true` if this map contains no key-value mappings.
`java.lang.Iterable<K>`	`keys()` Returns an iterator over the keys stored in this map.
`int`	`keySize()` Returns the number of keys in this map.
`void`	`keysToArray(K[] array)` Stores all keys of this map into `array`.
`HashMap<K,V>`	`keysToMap()` Stores all keys of this map into the resulting map.
`V`	`put(K key, V value)` Associates the specified value with the specified key in this map.
`void`	`putAll(HashMap<K,V> data)` Puts all elements in `data` into this hash map.
`void`	`putAllKeys(HashMap<K,?> data)` Puts all elements in `data` into this hash map.
`private V`	`putForNullKey(V value)` Offloaded version of put for null keys.
`V`	`remove(java.lang.Object key)` Removes the mapping of `key` and returns its value.
`(package private) void`	`resize(int newCapacity)` Rehashes the contents of this map into a new array with a larger capacity.
`int`	`size()` Returns the number of key-value mappings in this map.
`java.lang.String`	`toString()` Returns a textual representation of this map.
`(package private) void`	`transfer(HashMap.Entry[] newTable)` Transfers all entries from current table to newTable.
`java.lang.Iterable<V>`	`values()` Returns an iterator over the values stored in this map.

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

- Field Detail
  - DEFAULT_INITIAL_CAPACITY
```
private static final int DEFAULT_INITIAL_CAPACITY
```
    The default initial capacity - MUST be a power of two.
    
    See Also:
    
    Constant Field Values
  - MAXIMUM_CAPACITY
```
private static final int MAXIMUM_CAPACITY
```
    The maximum capacity, used if a higher value is implicitly specified by either of the constructors with arguments. MUST be a power of two <= 1<<30.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_LOAD_FACTOR
```
private static final float DEFAULT_LOAD_FACTOR
```
    The load factor used when none specified in constructor.
    
    See Also:
    
    Constant Field Values
  - table
```
private transient HashMap.Entry[] table
```
    The table, resized as necessary. Length MUST Always be a power of two.
  - size
```
private transient int size
```
    The number of key-value mappings contained in this map.
  - keySize
```
private transient int keySize
```
    The number of keys contained in this map.
  - threshold
```
private int threshold
```
    The next size value at which to resize (capacity * load factor).
  - loadFactor
```
private final float loadFactor
```
    The load factor for the hash table.
- Constructor Detail
  - HashMap
```
public HashMap(int initialCapacity,
               float loadFactor)
```
    Constructs an empty HashMap with the specified initial capacity and load factor.
    
    Parameters:
    
    initialCapacity - the initial capacity
    
    loadFactor - the load factor
    
    Throws:
    
    java.lang.IllegalArgumentException - if the initial capacity is negative or the load factor is nonpositive
  - HashMap
```
public HashMap(int initialCapacity)
```
    Constructs an empty HashMap with the specified initial capacity and the default load factor (0.75).
    
    Parameters:
    
    initialCapacity - the initial capacity.
    
    Throws:
    
    java.lang.IllegalArgumentException - if the initial capacity is negative.
  - HashMap
```
public HashMap()
```
    Constructs an empty HashMap with the default initial capacity (16) and the default load factor (0.75).
- Method Detail
  - containsKey
```
public boolean containsKey(java.lang.Object key)
```
    Returns true if this map contains a mapping for the specified key.
    
    Parameters:
    
    key - The key whose presence in this map is to be tested
    
    Returns:
    
    true if this map contains a mapping for the specified key.
  - hash
```
static int hash(int key)
```
    Applies a supplemental hash function to a given hashCode, which defends against poor quality hash functions. This is critical because HashMap uses power-of-two length hash tables, that otherwise encounter collisions for hashCodes that do not differ in lower bits. Note: Null keys always map to hash 0, thus index 0.
    
    Parameters:
    
    key - the key to hash
    
    Returns:
    
    the hash value
  - getEntry
```
final HashMap.Entry<K,V> getEntry(java.lang.Object key)
```
    Returns the entry associated with the specified key in the HashMap. Returns null if the HashMap contains no mapping for the key.
    
    Parameters:
    
    key - the key to return the stored object for
    
    Returns:
    
    the stored object or null
  - indexFor
```
static int indexFor(int hash,
                    int length)
```
    Returns index for hash code h.
    
    Parameters:
    
    hash - the hash code
    
    length - the length of the table
    
    Returns:
    
    the index
  - put
```
public V put(K key,
             V value)
```
    Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced.
    
    Parameters:
    
    key - key with which the specified value is to be associated
    
    value - value to be associated with the specified key
    
    Returns:
    
    the previous value associated with key, or null if there was no mapping for key. (A null return can also indicate that the map previously associated null with key.)
  - putForNullKey
```
private V putForNullKey(V value)
```
    Offloaded version of put for null keys.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the old value
  - addEntry
```
void addEntry(int hash,
              K key,
              V value,
              int bucketIndex)
```
    Adds a new entry with the specified key, value and hash code to the specified bucket. It is the responsibility of this method to resize the table if appropriate. Subclass overrides this to alter the behavior of put method.
    
    Parameters:
    
    hash - the hash code
    
    key - the key to add
    
    value - the value to add
    
    bucketIndex - the target bucket index
  - resize
```
void resize(int newCapacity)
```
    Rehashes the contents of this map into a new array with a larger capacity. This method is called automatically when the number of keys in this map reaches its threshold. If current capacity is MAXIMUM_CAPACITY, this method does not resize the map, but sets threshold to Integer.MAX_VALUE. This has the effect of preventing future calls.
    
    Parameters:
    
    newCapacity - the new capacity, MUST be a power of two; must be greater than current capacity unless current capacity is MAXIMUM_CAPACITY (in which case value is irrelevant).
  - transfer
```
void transfer(HashMap.Entry[] newTable)
```
    Transfers all entries from current table to newTable.
    
    Parameters:
    
    newTable - the target table
  - get
```
public V get(java.lang.Object key)
```
    Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
    
    Parameters:
    
    key - the key to search for
    
    Returns:
    
    the stored value, null if not found
    
    See Also:
    
    put(Object, Object)
  - remove
```
public V remove(java.lang.Object key)
```
    Removes the mapping of key and returns its value.
    
    Parameters:
    
    key - the key to remove the entry
    
    Returns:
    
    the value, null if there is not mapping for key
    
    Since:
    
    1.00
  - getForNullKey
```
private V getForNullKey()
```
    Offloaded version of get() to look up null keys. Null keys map to index 0. This null case is split out into separate methods for the sake of performance in the two most commonly used operations (get and put), but incorporated with conditionals in others.
    
    Returns:
    
    the result for a null key
  - size
```
public int size()
```
    Returns the number of key-value mappings in this map.
    
    Returns:
    
    the number of key-value mappings in this map
  - keySize
```
public int keySize()
```
    Returns the number of keys in this map.
    
    Returns:
    
    the number of keys
    
    Since:
    
    1.00
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this map contains no key-value mappings.
    
    Returns:
    
    true if this map contains no key-value mappings
  - values
```
public java.lang.Iterable<V> values()
```
    Returns an iterator over the values stored in this map.
    
    Returns:
    
    the iterator
    
    Since:
    
    1.00
  - entries
```
public java.lang.Iterable<HashMap.Entry<K,V>> entries()
```
    Returns an iterator over the entries stored in this map.
    
    Returns:
    
    the iterator
    
    Since:
    
    1.00
  - keys
```
public java.lang.Iterable<K> keys()
```
    Returns an iterator over the keys stored in this map.
    
    Returns:
    
    the iterator
    
    Since:
    
    1.00
  - clear
```
public void clear()
```
    Removes all of the mappings from this map. The map will be empty after this call returns.
  - toString
```
public java.lang.String toString()
```
    Returns a textual representation of this map.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the textual representation
  - keysToArray
```
public void keysToArray(K[] array)
```
    Stores all keys of this map into array.
    
    Parameters:
    
    array - the array to be modified as a side effect, nothing will happen if array == null, if array size is less than keySize() then only array.length keys will be copied
    
    Since:
    
    1.00
  - keysToMap
```
public HashMap<K,V> keysToMap()
```
    Stores all keys of this map into the resulting map. Values are not stored.
    
    Returns:
    
    a map with all keys
    
    Since:
    
    1.00
  - putAll
```
public void putAll(HashMap<K,V> data)
```
    Puts all elements in data into this hash map.
    
    Parameters:
    
    data - the elements to process
    
    Since:
    
    1.00
  - putAllKeys
```
public void putAllKeys(HashMap<K,?> data)
```
    Puts all elements in data into this hash map. Only keys are inserted, values are set to null.
    
    Parameters:
    
    data - the elements to process
    
    Since:
    
    1.00

Class HashMap<K,V>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_INITIAL_CAPACITY

MAXIMUM_CAPACITY

DEFAULT_LOAD_FACTOR

table

size

keySize

threshold

loadFactor

Constructor Detail

HashMap

HashMap

HashMap

Method Detail

containsKey

hash

getEntry

indexFor

put

putForNullKey

addEntry

resize

transfer

get

remove

getForNullKey

size

keySize

isEmpty

values

entries

keys

clear

toString

keysToArray

keysToMap

putAll

putAllKeys