org.apache.xerces.util
Class SoftReferenceSymbolTable
java.lang.Object
|
+--org.apache.xerces.util.SymbolTable
|
+--org.apache.xerces.util.SoftReferenceSymbolTable
- public class SoftReferenceSymbolTable
- extends SymbolTable
This symbol table uses SoftReferences to its String entries, which means that table entries
that have no references to them can be garbage collected when memory is needed. Thus, in
documents with very very large numbers of unique strings, using this SymbolTable will prevent
an out of memory error from occurring.
- Version:
- $Id: SoftReferenceSymbolTable.java 1358350 2012-07-06 19:04:35Z mrglavas $
- Author:
- Peter McCracken, IBM
- See Also:
SymbolTable
Constructor Summary |
SoftReferenceSymbolTable()
Constructs a new, empty SymbolTable with a default initial capacity (101)
and load factor, which is 0.75. |
SoftReferenceSymbolTable(int initialCapacity)
Constructs a new, empty SymbolTable with the specified initial capacity
and default load factor, which is 0.75. |
SoftReferenceSymbolTable(int initialCapacity,
float loadFactor)
Constructs a new, empty SymbolTable with the specified initial
capacity and the specified load factor. |
Method Summary |
java.lang.String |
addSymbol(char[] buffer,
int offset,
int length)
Adds the specified symbol to the symbol table and returns a
reference to the unique symbol. |
java.lang.String |
addSymbol(java.lang.String symbol)
Adds the specified symbol to the symbol table and returns a
reference to the unique symbol. |
protected void |
compact()
Reduces the capacity of and internally reorganizes this
SymbolTable, in order to accommodate and access its entries in
a more memory efficient way. |
boolean |
containsSymbol(char[] buffer,
int offset,
int length)
Returns true if the symbol table already contains the specified
symbol. |
boolean |
containsSymbol(java.lang.String symbol)
Returns true if the symbol table already contains the specified
symbol. |
protected void |
rebalance()
Randomly selects a new hash function and reorganizes this SymbolTable
in order to more evenly distribute its entries across the table. |
protected void |
rehash()
Increases the capacity of and internally reorganizes this
SymbolTable, in order to accommodate and access its entries more
efficiently. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
fBuckets
protected SoftReferenceSymbolTable.SREntry[] fBuckets
SoftReferenceSymbolTable
public SoftReferenceSymbolTable(int initialCapacity,
float loadFactor)
- Constructs a new, empty SymbolTable with the specified initial
capacity and the specified load factor.
- Parameters:
initialCapacity
- the initial capacity of the SymbolTable.loadFactor
- the load factor of the SymbolTable.- Throws:
java.lang.IllegalArgumentException
- if the initial capacity is less
than zero, or if the load factor is nonpositive.
SoftReferenceSymbolTable
public SoftReferenceSymbolTable(int initialCapacity)
- Constructs a new, empty SymbolTable with the specified initial capacity
and default load factor, which is 0.75.
- Parameters:
initialCapacity
- the initial capacity of the hashtable.- Throws:
java.lang.IllegalArgumentException
- if the initial capacity is less
than zero.
SoftReferenceSymbolTable
public SoftReferenceSymbolTable()
- Constructs a new, empty SymbolTable with a default initial capacity (101)
and load factor, which is 0.75.
addSymbol
public java.lang.String addSymbol(java.lang.String symbol)
- Adds the specified symbol to the symbol table and returns a
reference to the unique symbol. If the symbol already exists,
the previous symbol reference is returned instead, in order
guarantee that symbol references remain unique.
- Overrides:
addSymbol
in class SymbolTable
- Parameters:
symbol
- The new symbol.
addSymbol
public java.lang.String addSymbol(char[] buffer,
int offset,
int length)
- Adds the specified symbol to the symbol table and returns a
reference to the unique symbol. If the symbol already exists,
the previous symbol reference is returned instead, in order
guarantee that symbol references remain unique.
- Overrides:
addSymbol
in class SymbolTable
- Parameters:
buffer
- The buffer containing the new symbol.offset
- The offset into the buffer of the new symbol.length
- The length of the new symbol in the buffer.
rehash
protected void rehash()
- Increases the capacity of and internally reorganizes this
SymbolTable, in order to accommodate and access its entries more
efficiently. This method is called automatically when the
number of keys in the SymbolTable exceeds this hashtable's capacity
and load factor.
- Overrides:
rehash
in class SymbolTable
compact
protected void compact()
- Reduces the capacity of and internally reorganizes this
SymbolTable, in order to accommodate and access its entries in
a more memory efficient way. This method is called automatically when
the number of keys in the SymbolTable drops below 25% of this
hashtable's load factor (as a result of SoftReferences which have
been cleared).
rebalance
protected void rebalance()
- Randomly selects a new hash function and reorganizes this SymbolTable
in order to more evenly distribute its entries across the table. This
method is called automatically when the number keys in one of the
SymbolTable's buckets exceeds the given collision threshold.
- Overrides:
rebalance
in class SymbolTable
containsSymbol
public boolean containsSymbol(java.lang.String symbol)
- Returns true if the symbol table already contains the specified
symbol.
- Overrides:
containsSymbol
in class SymbolTable
- Parameters:
symbol
- The symbol to look for.
containsSymbol
public boolean containsSymbol(char[] buffer,
int offset,
int length)
- Returns true if the symbol table already contains the specified
symbol.
- Overrides:
containsSymbol
in class SymbolTable
- Parameters:
buffer
- The buffer containing the symbol to look for.offset
- The offset into the buffer.length
- The length of the symbol in the buffer.
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