7.10 Logical Filter Operators

7.10 Logical Filter Operators
Prev	7. Built-In Operations	Next

The logical Filter operators allows the user to assemble more complex filtering to be used in a single Pipe, instead of chaining multiple Pipes together to get the same effect.

And: The cascading.operation.filter.And Filter will logically 'and' the results of the constructor provided Filter instances. Logically, if Filter#isRemove() returns true for all given instances, this filter will return true.
Or: The cascading.operation.filter.Or Filter will logically 'or' the results of the constructor provided Filter instances. Logically, if Filter#isRemove() returns true for any of the given instances, this filter will return true.
Not: The cascading.operation.filter.Not Filter will logically 'not' (negation) the results of the constructor provided Filter instances. Logically, if Filter#isRemove() returns true for the given instance, this filter will return the opposite, false.
Xor: The cascading.operation.filter.Xor Filter will logically 'xor' (exclusive or) the results of the constructor provided Filter instances. Logically, if Filter#isRemove() returns true for all given instances, or returns false for all given instances, this filter will return true. Note that Xor can only be applied to two values.

Example 7.1. Combining Filters

// incoming -> "ip", "time", "method", "event", "status", "size"

FilterNull filterNull = new FilterNull();
RegexFilter regexFilter = new RegexFilter( "(GET|HEAD|POST)" );

And andFilter = new And( filterNull, regexFilter );

assembly = new Each( assembly, new Fields( "method" ), andFilter );

// outgoing -> "ip", "time", "method", "event", "status", "size"

Above, we are "and-ing" the two filters. Both must be satisfied for the data to pass through this one Pipe.

Prev	Up	Next
7.9 Assertions	Home	8. Best Practices