Package com.sun.xml.dtdparser
Class SimpleHashtable
java.lang.Object
com.sun.xml.dtdparser.SimpleHashtable
- All Implemented Interfaces:
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.
- Version:
- $Revision: 1.2 $
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
Hashtable collision list. -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate int
private SimpleHashtable.Entry
private int
private static final float
private SimpleHashtable.Entry[]
private int
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Constructor Summary
ConstructorsConstructorDescriptionConstructs a new, empty hashtable with a default capacity.SimpleHashtable
(int initialCapacity) Constructs a new, empty hashtable with the specified initial capacity. -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
Returns the value to which the specified key is mapped in this hashtable.getNonInterned
(String key) Returns the value to which the specified key is mapped in this hashtable ...boolean
Used to view this as an enumeration; returns true if there are more keys to be enumerated.keys()
Returns an enumeration of the keys in this hashtable.Used to view this as an enumeration; returns the next key in the enumeration.Maps the specifiedkey
to the specifiedvalue
in this hashtable.private void
rehash()
Increases the capacity of and internally reorganizes this hashtable, in order to accommodate and access its entries more efficiently.int
size()
Returns the number of keys in this hashtable.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface java.util.Enumeration
asIterator
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Field Details
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table
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current
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currentBucket
private int currentBucket -
count
private int count -
threshold
private int threshold -
loadFactor
private static final float loadFactor- See Also:
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Constructor Details
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SimpleHashtable
public SimpleHashtable(int initialCapacity) Constructs a new, empty hashtable with the specified initial capacity.- Parameters:
initialCapacity
- the initial capacity of the hashtable.
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SimpleHashtable
public SimpleHashtable()Constructs a new, empty hashtable with a default capacity.
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Method Details
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clear
public void clear() -
size
public int size()Returns the number of keys in this hashtable.- Returns:
- the number of keys in this hashtable.
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keys
Returns an enumeration of the keys in this hashtable.- Returns:
- an enumeration of the keys in this hashtable.
- See Also:
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hasMoreElements
public boolean hasMoreElements()Used to view this as an enumeration; returns true if there are more keys to be enumerated.- Specified by:
hasMoreElements
in interfaceEnumeration
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nextElement
Used to view this as an enumeration; returns the next key in the enumeration.- Specified by:
nextElement
in interfaceEnumeration
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get
Returns the value to which the specified key is mapped in this hashtable. -
getNonInterned
Returns the value to which the specified key is mapped in this hashtable ... the key isn't necessarily interned, though. -
rehash
private void rehash()Increases the capacity of and internally reorganizes this hashtable, in order to accommodate and access its entries more efficiently. This method is called automatically when the number of keys in the hashtable exceeds this hashtable's capacity and load factor. -
put
Maps the specifiedkey
to the specifiedvalue
in this hashtable. Neither the key nor the value can benull
.The value can be retrieved by calling the
get
method with a key that is equal to the original key.
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