stonehorse.candy

Class Choices

java.lang.Object

stonehorse.candy.Choices

public class Choices
extends Object

Expression replacements for the if-statements

cond(Supplier, Supplier, Supplier) is similar to switch-case-default as expression, and exists overloaded with arity on cases
ifelse(boolean, Supplier, Supplier) is if-then-else as expression. That is ternary operator with prefix syntax
ifNot(boolean, Supplier, Supplier) is like if-else-then as expression
when(boolean, Supplier) is if-then without else. Delivers null on else
whenNot(boolean, Supplier) is if-else without then. Delivers null on then
unless(Supplier, boolean, Supplier) is then-if-else as expression
unlessNull(Object, Supplier) Supplier value instead if T happen to be null. T if it is an object
mapOr(Object, Function, Supplier) return application of T to Function, unless null when Supplier value returns

doIfElse(boolean, Runnable, Runnable) ifelse for side effects
doWhen(boolean, Runnable) when for side effects
doWhenNot(boolean, Runnable) whenNot for side effects

requireAllNonNull(Object...) throws NPE if any is null

Method Summary

Modifier and Type	Method and Description
static <T> T	cond(Supplier<? extends T> v0) Always returns value of v0.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<? extends T> v1) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<? extends T> v2) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<? extends T> v3) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<? extends T> v4) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<Boolean> t4, Supplier<? extends T> v4, Supplier<? extends T> v5) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<Boolean> t4, Supplier<? extends T> v4, Supplier<Boolean> t5, Supplier<? extends T> v5, Supplier<? extends T> v6) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<Boolean> t4, Supplier<? extends T> v4, Supplier<Boolean> t5, Supplier<? extends T> v5, Supplier<Boolean> t6, Supplier<? extends T> v6, Supplier<? extends T> v7) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<Boolean> t4, Supplier<? extends T> v4, Supplier<Boolean> t5, Supplier<? extends T> v5, Supplier<Boolean> t6, Supplier<? extends T> v6, Supplier<Boolean> t7, Supplier<? extends T> v7, Supplier<? extends T> v8) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<Boolean> t4, Supplier<? extends T> v4, Supplier<Boolean> t5, Supplier<? extends T> v5, Supplier<Boolean> t6, Supplier<? extends T> v6, Supplier<Boolean> t7, Supplier<? extends T> v7, Supplier<Boolean> t8, Supplier<? extends T> v8, Supplier<? extends T> v9) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static <T> T	cond(Supplier<Boolean> t0, Supplier<? extends T> v0, Supplier<Boolean> t1, Supplier<? extends T> v1, Supplier<Boolean> t2, Supplier<? extends T> v2, Supplier<Boolean> t3, Supplier<? extends T> v3, Supplier<Boolean> t4, Supplier<? extends T> v4, Supplier<Boolean> t5, Supplier<? extends T> v5, Supplier<Boolean> t6, Supplier<? extends T> v6, Supplier<Boolean> t7, Supplier<? extends T> v7, Supplier<Boolean> t8, Supplier<? extends T> v8, Supplier<Boolean> t9, Supplier<? extends T> v9, Supplier<? extends T> v10) Evaluates each test t in order until true, in which case value of corresponding v is returned.
static void	doIfElse(boolean test, Runnable then, Runnable otherwise) Like ifelse without any return value, to express side effect
static void	doIfNot(boolean test, Runnable then, Runnable otherwise) Like ifNot without any return value, to express side effect
static void	doWhen(boolean test, Runnable then) Like when without any return value, to express side effect
static void	doWhenNot(boolean test, Runnable then) Like whenNo without any return value, to express side effect
static <T,V> V	either(T t, Predicate<? super T> p, Function<? super T,? extends V> then, Function<? super T,? extends V> otherwise) Transforms t with then if p test t or otherwise transforms t.
static <T> T	ifelse(boolean test, Supplier<T> then, Supplier<T> otherwise) Evaluates then and returns its value unless test is false, in which case otherwise is evaluated and its value returned.
static <T> T	ifNot(boolean test, Supplier<T> then, Supplier<T> otherwise) Evaluates then and returns its value unless test is true, in which case otherwise is evaluated and its value returned.
static <T,V> V	mapOr(T t, Function<T,V> f, Supplier<V> s) Return application of t to f, unless t is null, in which case evaluation of supplier s returns
static <T> void	requireAllNonNull(Object... nonNulls) Throws null pointer exception if any is null
static <T> T	unless(Supplier<T> then, boolean test, Supplier<T> otherwise) Evaluates then and returns its value unless test is true, in which case otherwise is evaluated and its value returned.
static <T> T	unlessNull(T t, Supplier<? extends T> then) t is delivered unless it is null, in which case the evaluation of then is returned
static <T> T	when(boolean test, Supplier<T> then) Then is evaluated and its value returned if test is true.
static <T> T	whenNot(boolean test, Supplier<T> then) Then is evaluated and its value returned if test is false.

Methods inherited from class java.lang.Object

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

Method Detail

cond

public static <T> T cond(Supplier<? extends T> v0)

Always returns value of v0. Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<? extends T> v1)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<? extends T> v2)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<? extends T> v3)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<? extends T> v4)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<Boolean> t4,
                         Supplier<? extends T> v4,
                         Supplier<? extends T> v5)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<Boolean> t4,
                         Supplier<? extends T> v4,
                         Supplier<Boolean> t5,
                         Supplier<? extends T> v5,
                         Supplier<? extends T> v6)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<Boolean> t4,
                         Supplier<? extends T> v4,
                         Supplier<Boolean> t5,
                         Supplier<? extends T> v5,
                         Supplier<Boolean> t6,
                         Supplier<? extends T> v6,
                         Supplier<? extends T> v7)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<Boolean> t4,
                         Supplier<? extends T> v4,
                         Supplier<Boolean> t5,
                         Supplier<? extends T> v5,
                         Supplier<Boolean> t6,
                         Supplier<? extends T> v6,
                         Supplier<Boolean> t7,
                         Supplier<? extends T> v7,
                         Supplier<? extends T> v8)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<Boolean> t4,
                         Supplier<? extends T> v4,
                         Supplier<Boolean> t5,
                         Supplier<? extends T> v5,
                         Supplier<Boolean> t6,
                         Supplier<? extends T> v6,
                         Supplier<Boolean> t7,
                         Supplier<? extends T> v7,
                         Supplier<Boolean> t8,
                         Supplier<? extends T> v8,
                         Supplier<? extends T> v9)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

cond

public static <T> T cond(Supplier<Boolean> t0,
                         Supplier<? extends T> v0,
                         Supplier<Boolean> t1,
                         Supplier<? extends T> v1,
                         Supplier<Boolean> t2,
                         Supplier<? extends T> v2,
                         Supplier<Boolean> t3,
                         Supplier<? extends T> v3,
                         Supplier<Boolean> t4,
                         Supplier<? extends T> v4,
                         Supplier<Boolean> t5,
                         Supplier<? extends T> v5,
                         Supplier<Boolean> t6,
                         Supplier<? extends T> v6,
                         Supplier<Boolean> t7,
                         Supplier<? extends T> v7,
                         Supplier<Boolean> t8,
                         Supplier<? extends T> v8,
                         Supplier<Boolean> t9,
                         Supplier<? extends T> v9,
                         Supplier<? extends T> v10)

Evaluates each test t in order until true, in which case value of corresponding v is returned. When all values are false, or null, returns the value of last v. Evaluations short circuits on truth. There are overloads with arity on test cases.

Example:

 cond(() -> false, () -> "No",
      () -> true, () -> "Yes",
      () -> true, () -> "Already caught" ,
      () -> "catch all")  => "Yes"
 

ifelse

public static <T> T ifelse(boolean test,
                           Supplier<T> then,
                           Supplier<T> otherwise)

Evaluates then and returns its value unless test is false, in which case otherwise is evaluated and its value returned. Behaves like if-then-else but is a expression. That is ternary operator with prefix syntax.

Example:

 ifelse(true, () -> "Yes", () -> "No") => "Yes"
 ifelse(false, () -> "Yes", () -> "No") => "No"
 

either

public static <T,V> V either(T t,
                             Predicate<? super T> p,
                             Function<? super T,? extends V> then,
                             Function<? super T,? extends V> otherwise)

Transforms t with then if p test t or otherwise transforms t. Behaves like ifelse, but then and otherwise are transformations of t depending of predicate p.

Example:

 either("Text", text->true, String::toUpperCase, String::toLowerCase) => "TEXT"
 either("Text", text->false, String::toUpperCase, String::toLowerCase) => "text"
 

when

public static <T> T when(boolean test,
                         Supplier<T> then)

Then is evaluated and its value returned if test is true. Otherwise null is returned

Example:

 when(true, () -> "Yes") => "Yes"
 when(false, () -> "Yes") => null
 

ifNot

public static <T> T ifNot(boolean test,
                          Supplier<T> then,
                          Supplier<T> otherwise)

Evaluates then and returns its value unless test is true, in which case otherwise is evaluated and its value returned.

Example:

 ifNot(true, () -> "Yes", () -> "No") => "No"
 ifNot(false, () -> "Yes", () -> "No") => "Yes"
 

whenNot

public static <T> T whenNot(boolean test,
                            Supplier<T> then)

Then is evaluated and its value returned if test is false. Otherwise null is returned

Example:

 whenNot(true, () -> "Yes") => null
 whenNot(false, () -> "Yes") => "Yes"
 

unless

public static <T> T unless(Supplier<T> then,
                           boolean test,
                           Supplier<T> otherwise)

Evaluates then and returns its value unless test is true, in which case otherwise is evaluated and its value returned.

Example:

 unless(() -> "Yes", false, () -> "No") => "Yes"
 unless(() -> "Yes", true, () -> "No") => "No"
 

unlessNull

public static <T> T unlessNull(T t,
                               Supplier<? extends T> then)

t is delivered unless it is null, in which case the evaluation of then is returned

Example:

 unlessNull("Yes", ()->"No") => "Yes"
 unlessNull(null, ()->"No") => "No"
 

mapOr

public static <T,V> V mapOr(T t,
                            Function<T,V> f,
                            Supplier<V> s)

Return application of t to f, unless t is null, in which case evaluation of supplier s returns

Example:

 mapOr("Yes", String::toUpperCase,()-> "No") => "YES"
 mapOr(((String)null), String::toUpperCase,()-> "No") => "No"
 

doWhen

public static void doWhen(boolean test,
                          Runnable then)

Like when without any return value, to express side effect

doWhenNot

public static void doWhenNot(boolean test,
                             Runnable then)

Like whenNo without any return value, to express side effect

doIfElse

public static void doIfElse(boolean test,
                            Runnable then,
                            Runnable otherwise)

Like ifelse without any return value, to express side effect

doIfNot

public static void doIfNot(boolean test,
                           Runnable then,
                           Runnable otherwise)

Like ifNot without any return value, to express side effect

requireAllNonNull

public static <T> void requireAllNonNull(Object... nonNulls)

Throws null pointer exception if any is null