Class Negate
- All Implemented Interfaces:
- Serializable,- EachOperation,- Filter,- Operation
The `Negate.isKeep()` method simply returns the opposite of the delegate's `isKeep()` method:
```java public boolean isKeep(TridentTuple tuple) { return !this.delegate.isKeep(tuple); } ```
The `Negate` filter is useful for dividing a Stream in two based on some boolean condition.
Suppose we had a Stream named `userStream` containing information about users, and a custom `Filter` implementation, `RegisteredUserFilter` that filtered out unregistered users. We could divide the `userStream` Stream into two separate Streams -- one for registered users, and one for unregistered users -- by doing the following:
```java Stream userStream = ...
Filter registeredFilter = new ResisteredUserFilter(); Filter unregisteredFilter = new Negate(registeredFilter);
Stream registeredUserStream = userStream.each(userStream.getOutputFields(), registeredFilter); Stream unregisteredUserStream = userStream.each(userStream.getOutputFields(), unregisteredFilter); ```
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidcleanup()When running in local mode, called when the local cluster is being shut down.booleanisKeep(TridentTuple tuple) Determines if a tuple should be filtered out of a stream.voidprepare(Map<String, Object> conf, TridentOperationContext context) Called when the `Operation` is first initialized.
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Constructor Details- 
Negate
 
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Method Details- 
isKeepDescription copied from interface:FilterDetermines if a tuple should be filtered out of a stream.
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prepareDescription copied from interface:OperationCalled when the `Operation` is first initialized.- Specified by:
- preparein interface- Operation
- Parameters:
- conf- the Storm configuration map
- context- the operation context which provides information such as the number of partitions in the stream, and the current partition index. It also provides methods for registering operation-specific metrics.
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cleanuppublic void cleanup()Description copied from interface:OperationWhen running in local mode, called when the local cluster is being shut down.
 
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