groovyx.gpars.extra166y
[Java] Class Ops

java.lang.Object
  groovyx.gpars.extra166y.Ops

public class Ops

Interfaces and utilities declaring per-element operations used within parallel methods on aggregates. This class provides type names for all operation signatures accepting zero, one or two arguments, and returning zero or one results, for parameterized types, as well as specializations to int, long, and double. In keeping with normal Java evaluation rules that promote, for example short to int, operation names for these smaller types are absent.

Preliminary release note: Some of the declarations in this class are likely to be moved elsewhere in the JDK libraries upon actual release, and most likely will not all nested in the same class.

The naming conventions are as follows:

• The name of the single method declared in each interface is simply op (short for "operate").
• An Op (short for "operation") maps a single argument to a result. Example: negating a value.
• The names for scalar ops accepting and returning the same type are prefaced by their type name.
• A BinaryOp maps two arguments to a result. Example: dividing two numbers
• A Reducer is an associative binary op accepting and returning values of the same type; where op(a, op(b, c)) should have the same result as op(op(a, b), c). Example: adding two numbers.
• Scalar binary ops accepting and returning the same type include their type name.
• Mixed-type operators are named just by their argument type names.
• A Generator takes no arguments and returns a result. Examples: random number generators, builders
• A Procedure accepts an argument but doesn't return a result. Example: printing a value. An Action is a Procedure that takes no arguments.
• A Predicate accepts a value and returns a boolean indicator that the argument obeys some property. Example: testing if a number is even.
• A BinaryPredicate accepts two values and returns a boolean indicator that the arguments obeys some relation. Example: testing if two numbers are relatively prime.
• Scalar versions of java.util.Comparator have the same properties as the Object version -- returning negative, zero, or positive if the first argument is less, equal, or greater than the second.

In addition to stated signatures, implementations of these interfaces must work safely in parallel. In general, this means methods should operate only on their arguments, and should not rely on ThreadLocals, unsafely published globals, or other unsafe constructions. Additionally, they should not block waiting for synchronization.

This class is normally best used via import static.

Ops

private Ops()

Copyright © 2008–2012 Václav Pech. All Rights Reserved.