Package org.apache.oro.text
Class GenericPatternCache
java.lang.Object
org.apache.oro.text.GenericPatternCache
- All Implemented Interfaces:
PatternCache
- Direct Known Subclasses:
PatternCacheFIFO
,PatternCacheFIFO2
,PatternCacheLRU
,PatternCacheRandom
This is the base class for all cache implementations provided in the
org.apache.oro.text package.
Although 4 subclasses of GenericPatternCache are provided with this
package, users may not derive subclasses from this class.
Rather, users should create their own implmentations of the
PatternCache
interface.- Since:
- 1.0
- Version:
- 2.0.8
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
The default capacity to be used by the GenericPatternCache subclasses provided with this package. -
Method Summary
Modifier and TypeMethodDescriptionfinal Pattern
addPattern
(String expression) Same as callingfinal Pattern
addPattern
(String expression, int options) Adds a pattern to the cache and returns the compiled pattern.final int
capacity()
Returns the maximum number of patterns that can be cached at one time.final Pattern
getPattern
(String expression) Same as callingfinal Pattern
getPattern
(String expression, int options) This method fetches a pattern from the cache.final int
size()
Returns the number of elements in the cache, not to be confused with thecapacity()
which returns the number of elements that can be held in the cache at one time.
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Field Details
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DEFAULT_CAPACITY
public static final int DEFAULT_CAPACITYThe default capacity to be used by the GenericPatternCache subclasses provided with this package. Its value is 20.- See Also:
-
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Method Details
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addPattern
Adds a pattern to the cache and returns the compiled pattern. This method is in principle almost identical togetPattern()
except for the fact that it throws a MalformedPatternException if an expression cannot be compiled.addPattern() is meant to be used when you expressly intend to add an expression to the cache and is useful for front-loading a cache with expressions before use. If the expression added does not already exist in the cache, it is compiled, added to the cache, and returned. If the compiled expression is already in the cache, it is simply returned.
The expected behavior of this method should be to start replacing patterns in the cache only after the cache has been filled to capacity.
- Specified by:
addPattern
in interfacePatternCache
- Parameters:
expression
- The regular expression to add to the cache.options
- The compilation options to use when compiling the expression.- Returns:
- The Pattern corresponding to the String representation of the regular expression.
- Throws:
MalformedPatternException
- If there is an error in compiling the regular expression.
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addPattern
Same as callingaddPattern(expression, 0);
- Specified by:
addPattern
in interfacePatternCache
- Parameters:
expression
- The regular expression to add to the cache.- Returns:
- The Pattern corresponding to the String representation of the regular expression.
- Throws:
MalformedPatternException
- If there is an error in compiling the regular expression.
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getPattern
public final Pattern getPattern(String expression, int options) throws MalformedCachePatternException This method fetches a pattern from the cache. It is nearly identical toaddPattern()
except that it doesn't throw a MalformedPatternException. If the pattern is not in the cache, it is compiled, placed in the cache, and returned. If the pattern cannot be compiled successfully, it throws a MalformedCachePatternException. Note that this exception is derived from RuntimeException, which means you are NOT forced to catch it by the compiler. Please refer toMalformedCachePatternException
for a discussion of when you should and shouldn't catch this exception.- Specified by:
getPattern
in interfacePatternCache
- Parameters:
expression
- The regular expression to fetch from the cache in compiled form.options
- The compilation options to use when compiling the expression.- Returns:
- The Pattern corresponding to the String representation of the regular expression.
- Throws:
MalformedCachePatternException
- If there is an error in compiling the regular expression.
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getPattern
Same as callinggetPattern(expression, 0)
- Specified by:
getPattern
in interfacePatternCache
- Parameters:
expression
- The regular expression to fetch from the cache in compiled form.- Returns:
- The Pattern corresponding to the String representation of the regular expression.
- Throws:
MalformedCachePatternException
- If there is an error in compiling the regular expression.
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size
public final int size()Returns the number of elements in the cache, not to be confused with thecapacity()
which returns the number of elements that can be held in the cache at one time.- Specified by:
size
in interfacePatternCache
- Returns:
- The current size of the cache (i.e., the number of elements currently cached).
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capacity
public final int capacity()Returns the maximum number of patterns that can be cached at one time.- Specified by:
capacity
in interfacePatternCache
- Returns:
- The maximum number of patterns that can be cached at one time.
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