Package io.blt.util

Class Ctr

java.lang.Object

io.blt.util.Ctr

public final class Ctr
extends Object

Static utility methods for operating on implementations of Collection and Map i.e. Containers.

For methods that return a modification of a passed container, the result will be of the same type if possible. This is accomplished using Obj.newInstanceOf(Object) and its limitations apply.

Method Summary

Modifier and Type	Method	Description
static <K, V, R, E extends Throwable> Map<K,R>	transformValues(Map<K,V> source, ThrowingFunction<? super V,R,E> transform)	Returns a new Map containing the entries of source with transform applied to the values.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

transformValues

public static <K,
V,
R,
E extends Throwable> Map<K,R> transformValues(Map<K,V> source,
 ThrowingFunction<? super V,R,E> transform)
                                                            throws E

Returns a new Map containing the entries of source with transform applied to the values.

If possible, the result is of the same type as the passed source map.

e.g.

 var scores = Map.of("Louis", 95, "Greg", 92, "Mike", 71, "Phil", 86);
 var grades = Ctr.transformValues(scores, score -> {
     if (score >= 90) {
         return "A";
     } else if (score >= 80) {
         return "B";
     } else if (score >= 70) {
         return "C";
     } else if (score >= 60) {
         return "D";
     } else {
         return "F";
     }
 });
 // grades = Map.of("Louis", "A", "Greg", "A", "Mike", "C", "Phil", "B")
 

Type Parameters:

K - map key type

V - map value type

R - returned map value type

E - type of transform throwable

Parameters:

source - Map whose values should be transformed

transform - value transformation function

Returns:

a new Map containing the entries of source with transform applied to the values

Throws:

E extends Throwable

See Also:

• Obj.newInstanceOf(Object)