Class MatchActionProcessor
To completely understand how to use MatchActionProcessor, you should first
look at MatchAction
and MatchActionInfo
.
A MatchActionProcessor is first initialized with
the desired PatternCompiler and PatternMatcher instances to use to compile
patterns and perform matches. Then, optionally, a field separator may
be registered with setFieldSeparator()
Finally, as many pattern action pairs as desired are registerd with
addAction()
before processing the input
with processMatches()
. Pattern action
pairs are processed in the order they were registered.
The look of added actions can closely mirror that of AWK when anonymous classes are used. Here's an example of how you might use MatchActionProcessor to extract only the second column of a semicolon delimited file:
import java.io.*; import org.apache.oro.text.*; import org.apache.oro.text.regex.*; public final class semicolon { public static final void main(String[] args) { MatchActionProcessor processor = new MatchActionProcessor(); try { processor.setFieldSeparator(";"); // Using a null pattern means to perform the action for every line. processor.addAction(null, new MatchAction() { public void processMatch(MatchActionInfo info) { // We assume the second column exists info.output.println(info.fields.elementAt(1)); } }); } catch(MalformedPatternException e) { e.printStackTrace(); System.exit(1); } try { processor.processMatches(System.in, System.out); } catch(IOException e) { e.printStackTrace(); System.exit(1); } } }You can redirect the following sample input to stdin to test the code:
1;Trenton;New Jersey 2;Annapolis;Maryland 3;Austin;Texas 4;Richmond;Virginia 5;Harrisburg;Pennsylvania 6;Honolulu;Hawaii 7;Santa Fe;New Mexico
- Since:
- 1.0
- Version:
- 2.0.8
- See Also:
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Constructor Summary
ConstructorsConstructorDescriptionDefault constructor for MatchActionProcessor.MatchActionProcessor
(PatternCompiler compiler, PatternMatcher matcher) Creates a new MatchActionProcessor instance initialized with the specified pattern compiler and matcher. -
Method Summary
Modifier and TypeMethodDescriptionvoid
Binds a patten to the default action.void
Binds a patten to the default action, providing options to be used to compile the pattern.void
addAction
(String pattern, int options, MatchAction action) Registers a pattern action pair, providing options to be used to compile the pattern.void
addAction
(String pattern, MatchAction action) Registers a pattern action pair.void
processMatches
(InputStream input, OutputStream output) This method reads the provided input one line at a time using the platform standart character encoding and for every registered pattern that is contained in the line it executes the associated MatchAction's processMatch() method.void
processMatches
(InputStream input, OutputStream output, String encoding) This method reads the provided input one line at a time and for every registered pattern that is contained in the line it executes the associated MatchAction's processMatch() method.void
processMatches
(Reader input, Writer output) This method reads the provided input one line at a time and for every registered pattern that is contained in the line it executes the associated MatchAction's processMatch() method.void
setFieldSeparator
(String separator) Sets the field separator to use when splitting a line into fields.void
setFieldSeparator
(String separator, int options) Sets the field separator to use when splitting a line into fields.
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Constructor Details
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MatchActionProcessor
Creates a new MatchActionProcessor instance initialized with the specified pattern compiler and matcher. The field separator is set to null by default, which means that matched lines will not be split into separate fields unless the field separator is set withsetFieldSeparator()
.- Parameters:
compiler
- The PatternCompiler to use to compile registered patterns.matcher
- The PatternMatcher to use when searching for matches.
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MatchActionProcessor
public MatchActionProcessor()Default constructor for MatchActionProcessor. Same as callingMatchActionProcessor(new Perl5Compiler(), new Perl5Matcher());
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Method Details
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addAction
public void addAction(String pattern, int options, MatchAction action) throws MalformedPatternException Registers a pattern action pair, providing options to be used to compile the pattern. If a pattern is null, the action is performed for every line of input.- Parameters:
pattern
- The pattern to bind to an action.options
- The compilation options to use for the pattern.action
- The action to associate with the pattern.- Throws:
MalformedPatternException
- If the pattern cannot be compiled.
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addAction
Binds a patten to the default action, providing options to be used to compile the pattern. The default action is to simply print the matched line to the output. If a pattern is null, the action is performed for every line of input.- Parameters:
pattern
- The pattern to bind to an action.options
- The compilation options to use for the pattern.- Throws:
MalformedPatternException
- If the pattern cannot be compiled.
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addAction
Binds a patten to the default action. The default action is to simply print the matched line to the output. If a pattern is null, the action is performed for every line of input.- Parameters:
pattern
- The pattern to bind to an action.- Throws:
MalformedPatternException
- If the pattern cannot be compiled.
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addAction
Registers a pattern action pair. If a pattern is null, the action is performed for every line of input.- Parameters:
pattern
- The pattern to bind to an action.action
- The action to associate with the pattern.- Throws:
MalformedPatternException
- If the pattern cannot be compiled.
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setFieldSeparator
Sets the field separator to use when splitting a line into fields. If the field separator is never set, or set to null, matched input lines are not split into fields.- Parameters:
separator
- A regular expression defining the field separator.options
- The options to use when compiling the separator.- Throws:
MalformedPatternException
- If the separator cannot be compiled.
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setFieldSeparator
Sets the field separator to use when splitting a line into fields. If the field separator is never set, or set to null, matched input lines are not split into fields.- Parameters:
separator
- A regular expression defining the field separator.- Throws:
MalformedPatternException
- If the separator cannot be compiled.
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processMatches
public void processMatches(InputStream input, OutputStream output, String encoding) throws IOException This method reads the provided input one line at a time and for every registered pattern that is contained in the line it executes the associated MatchAction's processMatch() method. If a field separator has been defined withsetFieldSeparator()
, the fields member of the MatchActionInfo instance passed to the processMatch() method is set to a Vector of Strings containing the split fields of the line. Otherwise the fields member is set to null. If no match was performed to invoke the action (i.e., a null pattern was registered), then the match member is set to null. Otherwise, the match member will contain the result of the match.The input stream, having been exhausted, is closed right before the method terminates and the output stream is flushed.
- Parameters:
input
- The input stream from which to read lines.output
- Where to send output.encoding
- The character encoding of the InputStream source. If you also want to define an output character encoding, you should useprocessMatches(Reader, Writer)
and specify the encodings when creating the Reader and Writer sources and sinks.- Throws:
IOException
- If an error occurs while reading input or writing output.- See Also:
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processMatches
This method reads the provided input one line at a time using the platform standart character encoding and for every registered pattern that is contained in the line it executes the associated MatchAction's processMatch() method. If a field separator has been defined withsetFieldSeparator()
, the fields member of the MatchActionInfo instance passed to the processMatch() method is set to a Vector of Strings containing the split fields of the line. Otherwise the fields member is set to null. If no match was performed to invoke the action (i.e., a null pattern was registered), then the match member is set to null. Otherwise, the match member will contain the result of the match.The input stream, having been exhausted, is closed right before the method terminates and the output stream is flushed.
- Parameters:
input
- The input stream from which to read lines.output
- Where to send output.- Throws:
IOException
- If an error occurs while reading input or writing output.- See Also:
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processMatches
This method reads the provided input one line at a time and for every registered pattern that is contained in the line it executes the associated MatchAction's processMatch() method. If a field separator has been defined withsetFieldSeparator()
, the fields member of the MatchActionInfo instance passed to the processMatch() method is set to a Vector of Strings containing the split fields of the line. Otherwise the fields member is set to null. If no match was performed to invoke the action (i.e., a null pattern was registered), then the match member is set to null. Otherwise, the match member will contain the result of the match.The input stream, having been exhausted, is closed right before the method terminates and the output stream is flushed.
- Parameters:
input
- The input stream from which to read lines.output
- Where to send output.- Throws:
IOException
- If an error occurs while reading input or writing output.- See Also:
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