cascading.operation.aggregator
Class MaxValue
java.lang.Object
cascading.operation.BaseOperation<ExtremaValueBase.Context>
cascading.operation.aggregator.ExtremaValueBase
cascading.operation.aggregator.MaxValue
- All Implemented Interfaces:
- DeclaresResults, Aggregator<ExtremaValueBase.Context>, Operation<ExtremaValueBase.Context>, Traceable, Serializable
public class MaxValue
- extends ExtremaValueBase
Class MaxValue is an Aggregator
that returns the maximum value encountered in the
current group.
As opposed to the Max
class, values are expected to be Comparable
types vs numeric representations and
the Comparable.compareTo(Object)
result is use for max comparison.
- See Also:
- Serialized Form
Fields inherited from interface cascading.operation.Operation |
ANY |
Constructor Summary |
MaxValue()
Constructs a new instance that returns the maximum value encountered in the field name "max". |
MaxValue(Fields fieldDeclaration)
Constructs a new instance that returns the maximum value encountered in the given fieldDeclaration field name. |
MaxValue(Fields fieldDeclaration,
Object... ignoreValues)
Constructs a new instance that returns the maximum value encountered in the given fieldDeclaration field name. |
FIELD_NAME
public static final String FIELD_NAME
- Field FIELD_NAME
- See Also:
- Constant Field Values
MaxValue
public MaxValue()
- Constructs a new instance that returns the maximum value encountered in the field name "max".
MaxValue
@ConstructorProperties(value="fieldDeclaration")
public MaxValue(Fields fieldDeclaration)
- Constructs a new instance that returns the maximum value encountered in the given fieldDeclaration field name.
- Parameters:
fieldDeclaration
- of type Fields
MaxValue
@ConstructorProperties(value={"fieldDeclaration","ignoreValues"})
public MaxValue(Fields fieldDeclaration,
Object... ignoreValues)
- Constructs a new instance that returns the maximum value encountered in the given fieldDeclaration field name.
Any argument matching an ignoredValue won't be compared.
- Parameters:
fieldDeclaration
- of type FieldsignoreValues
- of type Object...
compare
protected boolean compare(Comparable lhs,
Comparable rhs)
- Description copied from class:
ExtremaValueBase
- Allows subclasses to provide own comparison method.
- Specified by:
compare
in class ExtremaValueBase
- Parameters:
lhs
- Comparable typerhs
- Comparable type
- Returns:
- true if the rhs should be retained as the result value
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