conditional/README.adoc

# Conditional

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* link:#condition[Condition]
* link:#value[Value]

## Condition

If-then-else in a functional-style.

### if-then

[[source,java]]
----
if (isTrue()) {
    doSomething();
}
----

[[source,java]]
----
Condition.where(isTrue())
         .then(() -> doSomething());
----

### if-then-else

[[source,java]]
----
if (isTrue()) {
    doSomething();
} else {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.where(isTrue())
         .then(() -> doSomething())
         .otherwise(() -> doSomethingElse());
----

### if-and-then-else

[[source,java]]
----
if (isTrue() && isAlsoTrue()) {
    doSomething();
} else {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.where(isTrue())
         .and(() -> isAlsoTrue())
         .then(() -> doSomething())
         .otherwise(() -> doSomethingElse());
----

### if-or-then-else

[[source,java]]
----
if (isTrue() || alternativeIsTrue()) {
    doSomething();
} else {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.where(isTrue())
         .or(() -> alternativeIsTrue())
         .then(() -> doSomething())
         .otherwise(() -> doSomethingElse());
----

### if-not-then-else

[[source,java]]
----
if (!isFalse()) {
    doSomething();
} else {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.whereNot(isFalse())
         .then(() -> doSomething())
         .otherwise(() -> doSomethingElse());
----

### if-and-not-then-else

[[source,java]]
----
if (isTrue() || !isFalse()) {
    doSomething();
} else {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.where(isTrue())
         .andNot(() -> isFalse())
         .then(() -> doSomething())
         .otherwise(() -> doSomethingElse());
----

### if-or-not-then-else

[[source,java]]
----
if (isFalse() || !isAlsoFalse()) {
    doSomething();
} else {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.where(isFalse())
         .orNot(() -> isAlsoFalse())
         .then(() -> doSomething())
         .otherwise(() -> doSomethingElse());
----

### if-then-else-if

[[source,java]]
----
if (isFalse()) {
    doSomething();
} else if (isTrue()) {
    doSomethingElse();
}
----

[[source,java]]
----
Condition.where(isFalse())
         .then(() -> doSomething())
         .otherwise(() -> isTrue())
         .then(() -> doSomethingElse());
----

### if-then-if-then

[[source,java]]
----
if (isTrue()) {
    doSomething();
    if (isAlsoTrue()) {
        doSomethingElse();
    }
}
----

[[source,java]]
----
Condition.where(isTrue())
         .then(() -> doSomething())
         .and(() -> isAlsoTrue())
         .then(() -> doSomethingElse());
----

## Value

Values from an if-then-else in a functional-style.

Functional, and verbose, alternative to the ternary operator (`?:`).

### if-then-else

[[source,java]]
----
String result;
if (isTrue()) {
    result = TRUE;
} else {
    result = FALSE;
}
----

[[source,java]]
----
String result = isTrue() ? TRUE : FALSE;
----

[[source,java]]
----
final String result = Value.where(isTrue(), () -> TRUE, () -> FALSE);
----

[[source,java]]
----
final Optional<String> result = Value.where(isTrue(), () -> TRUE);
----

[[source,java]]
----
final String result = Value.<String>where(isTrue())
                           .then(() -> TRUE)
                           .otherwise(() -> FALSE);
----

### if-not-then-else

[[source,java]]
----
String result;
if (!isTrue()) {
    result = TRUE;
} else {
    result = FALSE;
}
----

[[source,java]]
----
final String result = Value.<String>whereNot(isTrue())
                           .then(() -> TRUE)
                           .otherwise(() -> FALSE);
----

### if-and-then-else

[[source,java]]
----
String result;
if (isTrue() && alternativeIsTrue()) {
    result = TRUE;
} else {
    result = FALSE;
}
----

[[source,java]]
----
final String result = Value.<String>where(isTrue())
                           .and(() -> alternativeIsTrue())
                           .then(() -> TRUE)
                           .otherwise(() -> FALSE);
----

### if-and-not-then-else

[[source,java]]
----
String result;
if (isTrue() && !alternativeIsFalse()) {
    result = TRUE;
} else {
    result = FALSE;
}
----

[[source,java]]
----
final String result = Value.<String>where(isTrue())
                           .andNot(() -> alternativeIsFalse())
                           .then(() -> TRUE)
                           .otherwise(() -> FALSE);
----

### if-or-then-else

[[source,java]]
----
String result;
if (isTrue() || alternativeIsTrue()) {
    result = TRUE;
} else {
    result = FALSE;
}
----

[[source,java]]
----
final String result = Value.<String>where(isTrue())
                           .or(() -> alternativeIsTrue())
                           .then(() -> TRUE)
                           .otherwise(() -> FALSE);
----

### if-or-not-then-else

[[source,java]]
----
String result;
if (isTrue() || !isFalse()) {
    result = TRUE;
} else {
    result = FALSE;
}
----

[[source,java]]
----
final String result = Value.<String>where(isTrue())
                           .orNot(() -> isFalse())
                           .then(() -> TRUE)
                           .otherwise(() -> FALSE);
----

### if-then

[[source,java]]
-----
Optional<String> result;
if (isTrue()) {
    result = Optional.of(TRUE);
} else {
    result = Optional.empty();
}
-----

[[source,java]]
-----
final Optional<String> result = Value.<String>where(isTrue())
                                     .then(() -> TRUE)
                                     .optional();
-----