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java.lang.Object org.apache.oro.text.regex.StringSubstitution org.apache.oro.text.regex.Perl5Substitution
Perl5Substitution implements a Substitution consisting of a
literal string, but allowing Perl5 variable interpolation referencing
saved groups in a match. This class is intended for use with
Util.substitute
.
The substitution string may contain variable interpolations referring to the saved parenthesized groups of the search pattern. A variable interpolation is denoted by $1, or $2, or $3, etc. If you want such expressions to be interpreted literally, you should set the numInterpolations parameter to INTERPOLATE_NONE . It is easiest to explain what an interpolated variable does by giving an example:
Tank b123: 85 Tank b256: 32 Tank b78: 22and use a numInterpolations value of INTERPOLATE_ALL and numSubs value (see
Util.substitute
)
of SUBSTITUTE_ALL, then your result will be:
Tank a123 85 Tank a256 32 Tank a78 22But if you set numInterpolations to 2 and keep numSubs with a value of SUBSTITUTE_ALL, your result is:
Tank a123 85 Tank a256 32 Tank a256 22Notice how the last substitution uses the same value for $1 as the second substitution.
A final thing to keep in mind is that if you use an interpolation variable that corresponds to a group not contained in the match, then it is interpreted as the empty string. So given the regular expression from the example, and a substitution expression of a$2, the result of the last sample input would be:
Tank a 85 Tank a 32 Tank a 22The special substitution $& will interpolate the entire portion of the input matched by the regular expression. $0 will do the same, but it is recommended that it be avoided because the latest versions of Perl use $0 to store the program name rather than duplicate the behavior of $&. Also, the result of substituting $ followed by a nonpositive integer is undefined. In order to include a $ in a substitution, it should be escaped with a backslash (e.g., "\\$0").
Perl5 doublequoted string case modification is also supported in the substitution. The following escape sequences are supported:
Substitution
,
Util
,
Util.substitute(org.apache.oro.text.regex.PatternMatcher, org.apache.oro.text.regex.Pattern, org.apache.oro.text.regex.Substitution, java.lang.String, int)
,
Substitution
,
StringSubstitution
Field Summary  
static int 
INTERPOLATE_ALL
A constant used when creating a Perl5Substitution indicating that interpolation variables should be computed relative to the most recent pattern match. 
static int 
INTERPOLATE_NONE
A constant used when creating a Perl5Substitution indicating that interpolation variables should be interpreted literally, effectively disabling interpolation. 
Constructor Summary  
Perl5Substitution()
Default constructor initializing substitution to a zero length String and the number of interpolations to INTERPOLATE_ALL . 

Perl5Substitution(java.lang.String substitution)
Creates a Perl5Substitution using the specified substitution and setting the number of interpolations to INTERPOLATE_ALL . 

Perl5Substitution(java.lang.String substitution,
int numInterpolations)
Creates a Perl5Substitution using the specified substitution and setting the number of interpolations to the specified value. 
Method Summary  
void 
appendSubstitution(java.lang.StringBuffer appendBuffer,
MatchResult match,
int substitutionCount,
PatternMatcherInput originalInput,
PatternMatcher matcher,
Pattern pattern)
Appends the substitution to a buffer containing the original input with substitutions applied for the pattern matches found so far. 
void 
setSubstitution(java.lang.String substitution)
Sets the substitution represented by this Perl5Substitution, also setting the number of interpolations to INTERPOLATE_ALL . 
void 
setSubstitution(java.lang.String substitution,
int numInterpolations)
Sets the substitution represented by this Perl5Substitution, also setting the number of interpolations to the specified value. 
Methods inherited from class org.apache.oro.text.regex.StringSubstitution 
getSubstitution, toString 
Methods inherited from class java.lang.Object 
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait 
Field Detail 
public static final int INTERPOLATE_ALL
public static final int INTERPOLATE_NONE
Constructor Detail 
public Perl5Substitution()
INTERPOLATE_ALL
.
public Perl5Substitution(java.lang.String substitution)
INTERPOLATE_ALL
.
substitution
 The string to use as a substitution.public Perl5Substitution(java.lang.String substitution, int numInterpolations)
substitution
 The string to use as a substitution.numInterpolations
 If set to INTERPOLATE_NONE, interpolation variables are
interpreted literally and not as references to the saved
parenthesized groups of a pattern match. If set to
INTERPOLATE_ALL , all variable interpolations
are computed relative to the pattern match responsible for
the current substitution. If set to a positive integer,
the first numInterpolations substitutions have
their variable interpolation performed relative to the
most recent match, but the remaining substitutions have
their variable interpolations performed relative to the
numInterpolations 'th match.Method Detail 
public void setSubstitution(java.lang.String substitution)
INTERPOLATE_ALL
.
You should use this method in order to avoid repeatedly allocating new
Perl5Substitutions. It is recommended that you allocate a single
Perl5Substitution and reuse it by using this method when appropriate.
setSubstitution
in class StringSubstitution
substitution
 The string to use as a substitution.public void setSubstitution(java.lang.String substitution, int numInterpolations)
substitution
 The string to use as a substitution.numInterpolations
 If set to INTERPOLATE_NONE, interpolation variables are
interpreted literally and not as references to the saved
parenthesized groups of a pattern match. If set to
INTERPOLATE_ALL , all variable interpolations
are computed relative to the pattern match responsible for
the current substitution. If set to a positive integer,
the first numInterpolations substitutions have
their variable interpolation performed relative to the
most recent match, but the remaining substitutions have
their variable interpolations performed relative to the
numInterpolations 'th match.public void appendSubstitution(java.lang.StringBuffer appendBuffer, MatchResult match, int substitutionCount, PatternMatcherInput originalInput, PatternMatcher matcher, Pattern pattern)
Substitution.appendSubstition()
for more details regarding the expected behavior of this method.
appendSubstitution
in interface Substitution
appendSubstitution
in class StringSubstitution
appendBuffer
 The buffer containing the new string resulting
from performing substitutions on the original input.match
 The current match causing a substitution to be made.substitutionCount
 The number of substitutions that have been
performed so far by Util.substitute.originalInput
 The original input upon which the substitutions are
being performed. This is a readonly parameter and is not modified.matcher
 The PatternMatcher used to find the current match.pattern
 The Pattern used to find the current match.


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