Package org.exolab.adaptx.util
Class HashMap
java.lang.Object
org.exolab.adaptx.util.HashMap
My implementation of a JDK 1.2 Map. I do not use synchronization,
so be careful in a threaded environment. I also do not specifically
"implements" java.util.Map, since support for JDK 1.1 is needed.
- Version:
- $Revision: 3633 $ $Date: 2003-03-01 08:38:44 +0100 (Sat, 01 Mar 2003) $
- Author:
- Keith Visco
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
The default number of buckets in this Map -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
Removes all entries from this Mapboolean
containsKey
(Object key) Returns true if the given object is a key contained in this Mapboolean
containsValue
(Object value) Returns true if the given object is a value contained in this Map
Note: Depending on the size of the Map, this could be a slow operation.entries()
Returns an interator for the entries of this Map.boolean
Returns true if the given Object is a HashMap which contains equivalent HashMap entries as this HashMap.Returns the value associated with the given keyint
hashCode()
Returns the hashCode for this Map.boolean
isEmpty()
Returns true if this map contains no entrieskeys()
void
Associated the specified value with the given key in this MapRemoves the association with the given Key in the Map.int
size()
Returns the number of associations in the Map
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Field Details
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DEFAULT_SIZE
public static final int DEFAULT_SIZEThe default number of buckets in this Map- See Also:
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Constructor Details
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HashMap
public HashMap()Creates a new HashMap with the default number of buckets -
HashMap
public HashMap(int size) Creates a new HashMap with the given number of buckets.- Parameters:
size
- , the number of buckets to use, this value must be a non-zero positive integer, if not the default size will be used.
Note:The number of buckets is not the same as the allocating space for a desired number of entries. If fact, if you know number of entries that will be in the hash, you might want to use a HashMap with a different implementation. This Map is implemented using separate chaining.
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Method Details
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clear
public void clear()Removes all entries from this Map -
containsKey
Returns true if the given object is a key contained in this Map- Returns:
- true if the given object is a key contained in this Map
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containsValue
Returns true if the given object is a value contained in this Map
Note: Depending on the size of the Map, this could be a slow operation. If you know the key an object would be associated with, contains key would be much faster, or simply do (get(key) != null).- Returns:
- true if the given object is a value contained in this Map
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entries
Returns an interator for the entries of this Map. Each element returned by a call to Iterator#next() is a Map.Entry.
Note: This is different than a JDK 1.2 Map because I didn't want to deal with implementing Sets at this point.- Returns:
- an Iterator for the entries of this Map.
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equals
Returns true if the given Object is a HashMap which contains equivalent HashMap entries as this HashMap. -
get
Returns the value associated with the given key- Returns:
- the value associated with the given key
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hashCode
public int hashCode()Returns the hashCode for this Map. The hash code is the sum of all the hash codes of each entry in the map -
isEmpty
public boolean isEmpty()Returns true if this map contains no entries- Returns:
- true if this map contains no entries
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keys
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put
Associated the specified value with the given key in this Map- Parameters:
key
- the object to associate with the given valuevalue
- the object to add an association in this Map
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remove
Removes the association with the given Key in the Map.- Parameters:
key
- the object key to remove the association for- Returns:
- the associated value being removed from this Map
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size
public int size()Returns the number of associations in the Map- Returns:
- the number of associations in the Map
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