9.10 Logical Filter Operators
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9.10 Logical Filter Operators

The logical Filter operators allow you to combine multiple filters to run in a single Pipe, instead of chaining multiple Pipes together to get the same logical result.

And

The cascading.operation.filter.And Filter performs a logical "and" on the results of the constructor-provided Filter instances. That is, if Filter#isRemove() returns true for all of the given instances, this filter returns true.

Or

The cascading.operation.filter.Or Filter performs a logical "or" on the results of the constructor-provided Filter instances. That is, if Filter#isRemove() returns true for any of the given instances, this filter returns true.

Not

The cascading.operation.filter.Not Filter performs a logical "not" (negation) on the results of the constructor-provided Filter instance. That is, if Filter#isRemove() returns true for the given instance, this filter returns false, and if Filter#isRemove() returns false for the given instance, this filter returns true.

Xor

The cascading.operation.filter.Xor Filter performs a logical "xor" (exclusive or) on the results of the constructor-provided Filter instances. Xor can only be applied to two instances at a time. It returns true if the two instances have different truth values, and false if they have the same truth value. That is, if Filter.isRemove() returns true for both, or returns false for both, this filter returns false; otherwise it returns true.

Example 9.1. 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"

The example above performs a logical "and" on the two filters. Both must be satisfied for the data to pass through this one Pipe.

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