de.unkrig.commons.text.pattern

Class PatternUtil

java.lang.Object

de.unkrig.commons.text.pattern.PatternUtil

public final class PatternUtil
extends java.lang.Object

Pattern-related utility methods.

Method Summary

Modifier and Type	Method and Description
static Function<java.util.regex.Matcher,java.lang.String>	constantReplacer(java.lang.String string) Return a replacer which always returns the given string.
static java.lang.String	replaceAll(java.util.regex.Matcher matcher, Function<java.util.regex.Matcher,java.lang.String> replacer) The generalized form of Matcher.replaceAll(String): The replacement for a match is not formed from a "replacement string" (with variables "$0", "$1", ...), but is computed by the replacer.
static int	replaceAll(java.io.Reader in, java.util.regex.Pattern pattern, Function<java.util.regex.Matcher,java.lang.String> replacer, java.io.Writer out, int initialBufferCapacity) Reads characters from in, finds all matches of pattern, replaces each match with the result of the replacer, and writes the result to out.
static void	replaceAll(java.io.Reader in, java.util.regex.Pattern pattern, java.lang.String replacementString, java.io.Writer out) Reads text from in, replaces all matches of pattern according to the replacementString, and writes the result to out.
static Function<java.util.regex.Matcher,java.lang.String>	replacementStringReplacer(java.lang.String replacementString)
static int	replaceSystemProperties(java.io.Reader in, java.io.Writer out) Reads text from in, replaces all matches of "${system-property-name}" with the value of the system property, and writes the result to out.
static Function<java.util.regex.Matcher,java.lang.String>	systemPropertyReplacer() Returns a replacer which returns the value of the system property named by group #1 of the match.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

replaceAll

public static void replaceAll(java.io.Reader in,
                              java.util.regex.Pattern pattern,
                              java.lang.String replacementString,
                              java.io.Writer out)
                       throws java.io.IOException

Reads text from in, replaces all matches of pattern according to the replacementString, and writes the result to out.

The pattern search is stream-oriented, not line-oriented, i.e. matches are found even across line boundaries. Thus the pattern should have been compiled with the Pattern.MULTILINE flag.

Throws:

java.io.IOException

See Also:

For the format of the replacementString

constantReplacer

public static Function<java.util.regex.Matcher,java.lang.String> constantReplacer(@Nullable
                                                                                  java.lang.String string)

Return a replacer which always returns the given string.

Opposed to replacementStringReplacer(String), "$" and "\" have no special meaning.

See Also:

replacementStringReplacer(String), systemPropertyReplacer()

replacementStringReplacer

public static Function<java.util.regex.Matcher,java.lang.String> replacementStringReplacer(java.lang.String replacementString)

Returns:

A replacer which forms the replacement from the match and the given replacementString

See Also:

For the format of the replacementString, constantReplacer(String), systemPropertyReplacer()

systemPropertyReplacer

public static Function<java.util.regex.Matcher,java.lang.String> systemPropertyReplacer()

Returns a replacer which returns the value of the system property named by group #1 of the match.

Example:

   PatternUtil.replaceAll(
       Pattern.compile("\\$\\{([^}]+)}").matcher("file.separator is ${file.separator}"),
       PatternUtil.systemPropertyReplacer()
   )
 

See Also:

constantReplacer(String), replacementStringReplacer(String)

replaceSystemProperties

public static int replaceSystemProperties(java.io.Reader in,
                                          java.io.Writer out)
                                   throws java.io.IOException

Reads text from in, replaces all matches of "${system-property-name}" with the value of the system property, and writes the result to out.

Returns:

The number of replacements that were executed

Throws:

java.io.IOException

replaceAll

public static java.lang.String replaceAll(java.util.regex.Matcher matcher,
                                          Function<java.util.regex.Matcher,java.lang.String> replacer)

The generalized form of Matcher.replaceAll(String): The replacement for a match is not formed from a "replacement string" (with variables "$0", "$1", ...), but is computed by the replacer. If the replacer returns null for a match, then the match is not replaced.

replaceAll

public static int replaceAll(java.io.Reader in,
                             java.util.regex.Pattern pattern,
                             Function<java.util.regex.Matcher,java.lang.String> replacer,
                             java.io.Writer out,
                             int initialBufferCapacity)
                      throws java.io.IOException

Reads characters from in, finds all matches of pattern, replaces each match with the result of the replacer, and writes the result to out. If the replacer returns null for a match, then the match is not replaced.

The pattern search is stream-oriented, not line-oriented, i.e. matches are found even across line boundaries. Therefore the pattern should have been compiled with the Pattern.MULTILINE flag.

This method attempts to load as few characters into memory as possible. Notice, however, that in particular the usage of "greedy quantifiers", for example "a.*b", can lead to all the remaining content being read into memory.

Parameters:

initialBufferCapacity - The initial capacity of the temporary CharBuffer that is used for pattern matching; the buffer will automatically be resized as necessary; 4096 may be a good value

Returns:

The number of replacements that were executed

Throws:

java.io.IOException