public class Count extends AbstractFaAction
counts matches and can then be used with If to perform
conditional actions depending on whether a threshold count is
reached. To retrieve and store the current count,
the callback obtains a Map from a MapProvider
that has to be in the DfaRun.clientData field of
the calling DfaRun. The value is stored in the
Map with the key specified in the constructor. The
same key may be used in a Printf callback's format like
"%(key) to insert the value into the output stream.
Whenever invoke is called for a
successfull match, the counter is incremented by one.
The counter can be tested against a threshold with the Verifier returned by ge(). Typically this verifier
will be passed to an instance of If. An example is
Count cnt = new Count("no_of_fishes");
...
nfa.or("start", cnt.reset())
.or("fish", cnt)
.or("end", new If(cnt.ge(2), a1, a2))
The callback of If will call ok() on the
Verifier returned by cnt.ge(2) and
perform either action a1 or a2.
To add another increment then 1 to the counter, use the action
created by add(int).
| Constructor and Description |
|---|
Count(java.lang.String key)
create a counter callback which records the its value with
key. |
| Modifier and Type | Method and Description |
|---|---|
AbstractFaAction |
add(int incr)
returns an
FaAction which changes the counter
according to the
given increment incr. |
Verifier |
ge(int threshold)
returns a
Verifier which returns true if
the counter is greater than or equal to the given
threshold. |
int |
getValue(DfaRun r)
given the
DfaRun which has just the right
MapProvider in its clientData field,
this returns the current counter value. |
void |
invoke(java.lang.StringBuilder yytext,
int start,
DfaRun r)
is called by methods of
DfaRun in case of a
match. |
AbstractFaAction |
reset()
returns an
FaAction which resets the counter to
zero. |
mergeWith, setPrioritypublic Count(java.lang.String key)
create a counter callback which records the its value with
key.
public void invoke(java.lang.StringBuilder yytext,
int start,
DfaRun r)
FaActionis called by methods of DfaRun in case of a
match. Parameter yytext contains the matching text
from position start onwards. The callback may change
the whole of yytext, but the under most
circumstances, only the matching text should be
changed. Parameter runner is the DfaRun
object which called this function. Of interest are its fields
DfaRun.clientData and DfaRun.collect.
public int getValue(DfaRun r)
given the DfaRun which has just the right
MapProvider in its clientData field,
this returns the current counter value.
public AbstractFaAction reset()
returns an FaAction which resets the counter to
zero.
public AbstractFaAction add(int incr)
FaAction which changes the counter
according to the
given increment incr. Example use:
Count cnt = new Count(7);
...
nfa.or("pattern with weight 2", cnt.add(2));