org.apache.xerces.parsers
public class CachingParserPool extends Object
Once the caching parser pool is constructed, specific parser instances are created by calling the appropriate factory method on the parser pool.
Note: There is a performance penalty for using a caching parser pool due to thread safety. Access to the symbol table and grammar pool must be synchronized to ensure the safe operation of the symbol table and grammar pool.
Note: If performance is critical, then another mechanism needs to be used instead of the caching parser pool. One approach would be to create parser instances that do not share these structures. Instead, each instance would get its own copy to use while parsing. This avoids the synchronization overhead at the expense of more memory and the time required to copy the structures for each new parser instance. And even when a parser instance is re-used, there is a potential for a memory leak due to new symbols being added to the symbol table over time. In other words, always take caution to make sure that your application is thread-safe and avoids leaking memory.
Version: $Id: CachingParserPool.java,v 1.12 2004/02/24 23:15:56 mrglavas Exp $
Nested Class Summary | |
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static class | CachingParserPool.ShadowedGrammarPool
Shadowed grammar pool.
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static class | CachingParserPool.SynchronizedGrammarPool
Synchronized grammar pool.
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Field Summary | |
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static boolean | DEFAULT_SHADOW_GRAMMAR_POOL Default shadow grammar pool (false). |
static boolean | DEFAULT_SHADOW_SYMBOL_TABLE Default shadow symbol table (false). |
protected boolean | fShadowGrammarPool
Shadow the grammar pool for new parser instances. |
protected boolean | fShadowSymbolTable
Shadow the symbol table for new parser instances. |
protected XMLGrammarPool | fSynchronizedGrammarPool
Grammar pool. |
protected SymbolTable | fSynchronizedSymbolTable
Symbol table. |
Constructor Summary | |
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CachingParserPool() Default constructor. | |
CachingParserPool(SymbolTable symbolTable, XMLGrammarPool grammarPool)
Constructs a caching parser pool with the specified symbol table
and grammar pool.
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Method Summary | |
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DOMParser | createDOMParser() Creates a new DOM parser. |
SAXParser | createSAXParser() Creates a new SAX parser. |
SymbolTable | getSymbolTable() Returns the symbol table. |
XMLGrammarPool | getXMLGrammarPool() Returns the grammar pool. |
void | setShadowSymbolTable(boolean shadow)
Sets whether new parser instance receive shadow copies of the
main symbol table.
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Parameters: symbolTable The symbol table. grammarPool The grammar pool.
Parameters: shadow If true, new parser instances use shadow copies of the main symbol table and are not allowed to add new symbols to the main symbol table. New symbols are added to the shadow symbol table and are local to the parser instance. If false, new parser instances are allowed to add new symbols to the main symbol table.