Apache UIMA Ruta Guide and Reference - Apache UIMA - The ...

Learning by Example
This rule annotates everything between two “PERIOD” annotations with the type “Sentence”.
Please note that the resulting annotations are probably invisible, if they start or end with an filtered
type.
Rule elements can contain more then one condition. The rule in the next example tries to identify
headlines, which are bold, underlined and end with a colon.
DECLARE Headline;
Paragraph{CONTAINS(Bold, 90, 100, true),
CONTAINS(Underlined, 90, 100, true), ENDSWITH(COLON)
-> MARK(Headline)};
The matching condition of this rule element is given with the type “Paragraph”, thus the rule takes
a look at all Paragraph annotations. The rule matches only if the three conditions, separated by
commas, are fulfilled. The first condition “CONTAINS(Bold, 90, 100, true)” states that 90%-100%
of the matched paragraph annotation should also be annotated with annotations of the type “Bold”.
The boolean parameter “true” indicates that amount of Bold annotations should be calculated
relatively to the matched annotation. The two numbers “90,100” are, therefore, interpreted as
percent amounts. The exact calculation of the coverage is dependent on the tokenization of the
document and is neglected for now. The second condition “CONTAINS(Underlined, 90, 100,
true)” consequently states that the paragraph should also contain at least 90% of annotations of
the type “underlined”. The third condition “ENDSWITH(COLON)” finally forces the Paragraph
annotation to end with a colon. It is only fulfilled, if there is an annotation of the type “COLON”,
which has an end offset equal to the end offset of the matched Paragraph annotation.
The readability and maintenance of rules does not increase, if more conditions are added. One
of the strengths of the UIMA Ruta language is that it provides different approaches to solve an
annotation task. The next two examples introduce actions for transformation-based rules.
Headline{-CONTAINS(W) -> UNMARK(Headline)};
This rule consists of one condition and one action. The condition “-CONTAINS(W)” is negated
(indicated by the character “-”), and is therefore only fulfilled, if there are no annotations of the
type “W” within the bound of the matched Headline annotation. The action “UNMARK(Headline)”
removes the matched Headline annotation. Put into simple words, headlines that contain no words
at all are not headlines.
The next rule does not remove an annotation, but changes its offsets dependent on the context.
Headline{-> SHIFT(Headline, 1, 2)} COLON;
Here, the action “SHIFT(Headline, 1, 2)” expands the matched Headline annotation to the next
colon, if that Headline annotation is followed by a COLON annotation.
UIMA Ruta rules can contain arbitrary conditions and actions, which is illustrated by the next
example.
DECLARE Month, Year, Date;
ANY{INLIST(MonthsList) -> MARK(Month), MARK(Date,1,3)}
PERIOD? NUM{REGEXP(".{2,4}") -> MARK(Year))};
This rule consists of three rule elements. The first one matches on every token, which has a
covered text that occurs in a word lists named “MonthsList”. The second rule element is optional
and does not need to be fulfilled, which is indicated by the quantifier “?”. The last rule element
UIMA Ruta Version 2.0.1 Apache UIMA Ruta Overview 5