August 2017
Beginner to intermediate
284 pages
6h 51m
English
Content preview from Mastering Apache Storm
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Trident filter
A Trident filter gets a set of fields as input and returns either true or false depending on whether a certain condition is satisfied or not. If true is returned, then the tuple is kept in the output stream; otherwise, the tuple is removed from the stream.
We can write a custom Trident filter by extending the storm.trident.operation.BaseFilter class and implementing the isKeep(TridentTuple tuple) method.
Let's write a sample Trident filter that will check whether the sum of the input fields is even or odd. If the sum is even, then the Trident filter emits true; otherwise it emits false:
public static class CheckEvenSumFilter extends BaseFilter{ private static final long serialVersionUID = 7L; public boolean isKeep(TridentTuple ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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