Message and priority overriding
You can change a rule’s message by specifying a message
attribute on the rule element. This will override the previous
value and change the message the rule will print on the report.
Similarly, the priority of a rule can be changed via a nested
element. Using priority, you can deactivate some rules based on a
minimum priority threshold (set using the -min CLI option).
Priority is an integer ranging from 1 to 5, with 1 being the highest
priority.
Putting things together, the following rule reference lowers the priority
of EmptyCatchBlock to 5, such that e.g. using the -min 4 CLI parameters
will cause the rule to be ignored.
<rule ref="category/java/errorprone.xml/EmptyCatchBlock"
message="Empty catch blocks should be avoided" >
<priority>5</priority>
</rule>
Rule properties
Properties make it easy to customise the behaviour of a rule directly from the xml. They come in several types, which correspond to the type of their values. For example, NPathComplexity declares a property “reportLevel”, with an integer value type, and which corresponds to the threshold above which a method will be reported. If you believe that its default value of 200 is too high, you could lower it to e.g. 150 in the following way:
<rule ref="category/java/design.xml/NPathComplexity">
<properties>
<property name="reportLevel">
<value>150</value>
</property>
</properties>
</rule>
Properties are assigned a value with a property element, which should mention the name of a property as an attribute. The value of the property can be specified either in the content of the element, like above, or in the value attribute, e.g.
<property name="reportLevel" value="150"/>
All property assignments must be enclosed in a properties element, which is itself inside a rule element.
Some properties take multiple values (a list), in which case you can provide them all by delimiting them with a delimiter character. It is usually a pipe (‘|’), or a comma (‘,’) for numeric properties, e.g.
<property name="legalCollectionTypes"
value="java.util.ArrayList|java.util.Vector|java.util.HashMap"/>
These properties are referred to as multivalued properties in this documentation.