org.apache.tomcat.util.collections
Class SimpleHashtable
java.lang.Object
org.apache.tomcat.util.collections.SimpleHashtable
- Enumeration
public final class SimpleHashtable
extends java.lang.Object
implements Enumeration
This class implements a special purpose hashtable. It works like a
normal
java.util.Hashtable
except that:
- Keys to "get" are strings which are known to be interned,
so that "==" is used instead of "String.equals". (Interning
could be document-relative instead of global.)
- It's not synchronized, since it's to be used only by
one thread at a time.
- The keys () enumerator allocates no memory, with live
updates to the data disallowed.
- It's got fewer bells and whistles: fixed threshold and
load factor, no JDK 1.2 collection support, only keys can be
enumerated, things can't be removed, simpler inheritance; more.
The overall result is that it's less expensive to use these in
performance-critical locations, in terms both of CPU and memory,
than
java.util.Hashtable
instances. In this package
it makes a significant difference when normalizing attributes,
which is done for each start-element construct.
SimpleHashtable() - Constructs a new, empty hashtable with a default capacity.
|
SimpleHashtable(int initialCapacity) - Constructs a new, empty hashtable with the specified initial
capacity.
|
void | clear()
|
Object | get(String key) - Returns the value to which the specified key is mapped in this
hashtable ...
|
Object | getInterned(String key) - Returns the value to which the specified key is mapped in this hashtable.
|
boolean | hasMoreElements() - Used to view this as an enumeration; returns true if there
are more keys to be enumerated.
|
Enumeration | keys() - Returns an enumeration of the keys in this hashtable.
|
Object | nextElement() - Used to view this as an enumeration; returns the next key
in the enumeration.
|
Object | put(Object key, Object value) - Maps the specified
key to the specified
value in this hashtable.
|
Object | remove(Object key)
|
int | size() - Returns the number of keys in this hashtable.
|
SimpleHashtable
public SimpleHashtable()
Constructs a new, empty hashtable with a default capacity.
SimpleHashtable
public SimpleHashtable(int initialCapacity)
Constructs a new, empty hashtable with the specified initial
capacity.
initialCapacity
- the initial capacity of the hashtable.
get
public Object get(String key)
Returns the value to which the specified key is mapped in this
hashtable ... the key isn't necessarily interned, though.
getInterned
public Object getInterned(String key)
Returns the value to which the specified key is mapped in this hashtable.
hasMoreElements
public boolean hasMoreElements()
Used to view this as an enumeration; returns true if there
are more keys to be enumerated.
keys
public Enumeration keys()
Returns an enumeration of the keys in this hashtable.
- an enumeration of the keys in this hashtable.
Enumeration
nextElement
public Object nextElement()
Used to view this as an enumeration; returns the next key
in the enumeration.
put
public Object put(Object key,
Object value)
Maps the specified
key
to the specified
value
in this hashtable. Neither the key nor the
value can be
null
.
The value can be retrieved by calling the
get
method
with a key that is equal to the original key.
remove
public Object remove(Object key)
size
public int size()
Returns the number of keys in this hashtable.
- the number of keys in this hashtable.
Copyright B) 2000-2003 Apache Software Foundation. All Rights Reserved.