Comparable interface
Comparable is an interface, protocol, or mechanism that specifies whether values of a type can be compared or ordered.
100 Java Mistakes and How to Avoid Them
Comparable is a Java interface whose implementation defines a natural ordering for instances through compareTo.
- How it is used
- Defines natural ordering for Java objects and exposes comparison mistakes that can silently misorder data.
- How deep it goes
- Details sign-based compareTo rules and focused failures, while limiting collection internals to a collision-dependent HashSet case.
- Examples
- Uses boolean wrappers, a name-and-age User record, and mutable StringBuilder values stored in HashSet.
- What you can do after
- Diagnose/debug comparison code by checking signs, equality results, and unsafe mutable or inconsistent collection keys.
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Clojure: The Essential Reference
The Java Comparable interface defines a natural ordering for instances of a class through its compareTo method.
- How it is used
- Supplies natural ordering to Clojure’s default comparison and sorting of compatible custom objects.
- How deep it goes
- Explains comparison results, compatibility requirements, exceptions, and a worked record implementation without detailing Java interface internals.
- Examples
- Uses distance-ordered point and gas-station records, plus sorted-map keys, to demonstrate ordering.
- What you can do after
- Build it from scratch by implementing `compareTo` on a Clojure record so its instances can be sorted.
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Classic Computer Science Problems in Swift: Essential techniques for practicing programmers
Comparable is a Swift standard-library protocol for types whose values can be ordered relative to one another.
- How it is used
- Supports ranking search nodes so A* can prioritize candidates by combined cost and heuristic.
- How deep it goes
- Defines comparison for a concrete generic Node type but does not survey Comparable requirements beyond the shown operators.
- Examples
- Uses a generic Node whose < operator compares cost plus heuristic and whose == operator compares reference identity.
- What you can do after
- Apply it via Swift operator overloads to rank custom search nodes for priority-based algorithms.
Related concepts
- compareTo methodhas part · The compareTo method compares an object with another value and returns a negative, zero, or positive integer indicating their relative ordering.
- StringBuilderimplemented by · StringBuilder is a mutable character-sequence type designed for efficiently constructing and modifying text through repeated operations.
- compareused by · compare is a Clojure function that returns a negative, zero, or positive integer indicating the relative order of two comparable values.
- type constraintused by · A type constraint is a rule that restricts admissible types or type arguments by requiring specified relationships, structures, properties, or supported operations.
- comparison functionalternative to · A comparison function or strategy compares two values and indicates their relative ordering, and sometimes whether they are equivalent.
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