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CrazyLambdas methods #179

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54 changes: 34 additions & 20 deletions ...unctional-programming/5-1-1-crazy-lambdas/src/main/java/com/bobocode/fp/CrazyLambdas.java
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
import java.math.BigDecimal;
import java.util.Comparator;
import java.util.Map;
import java.util.Random;
import java.util.function.*;

/**
Expand All @@ -27,7 +28,7 @@ public class CrazyLambdas {
* @return a string supplier
*/
public static Supplier<String> helloSupplier() {
throw new ExerciseNotCompletedException();
return () -> "Hello";
}

/**
Expand All @@ -36,7 +37,7 @@ public static Supplier<String> helloSupplier() {
* @return a string predicate
*/
public static Predicate<String> isEmptyPredicate() {
throw new ExerciseNotCompletedException();
return String::isEmpty;
}

/**
Expand All @@ -46,7 +47,7 @@ public static Predicate<String> isEmptyPredicate() {
* @return function that repeats Strings
*/
public static BiFunction<String, Integer, String> stringMultiplier() {
throw new ExerciseNotCompletedException();
return String::repeat;
}

/**
Expand All @@ -56,7 +57,7 @@ public static BiFunction<String, Integer, String> stringMultiplier() {
* @return function that converts adds dollar sign
*/
public static Function<BigDecimal, String> toDollarStringFunction() {
throw new ExerciseNotCompletedException();
return number -> "$" + number;
}

/**
Expand All @@ -68,7 +69,7 @@ public static Function<BigDecimal, String> toDollarStringFunction() {
* @return a string predicate
*/
public static Predicate<String> lengthInRangePredicate(int min, int max) {
throw new ExerciseNotCompletedException();
return str -> min <= str.length() && str.length() < max;
}

/**
Expand All @@ -77,7 +78,7 @@ public static Predicate<String> lengthInRangePredicate(int min, int max) {
* @return int supplier
*/
public static IntSupplier randomIntSupplier() {
throw new ExerciseNotCompletedException();
return () -> new Random().nextInt();
}


Expand All @@ -87,7 +88,7 @@ public static IntSupplier randomIntSupplier() {
* @return int operation
*/
public static IntUnaryOperator boundedRandomIntSupplier() {
throw new ExerciseNotCompletedException();
return bound -> new Random().nextInt(bound);
}

/**
Expand All @@ -96,7 +97,7 @@ public static IntUnaryOperator boundedRandomIntSupplier() {
* @return square operation
*/
public static IntUnaryOperator intSquareOperation() {
throw new ExerciseNotCompletedException();
return num -> num * num;
}

/**
Expand All @@ -105,7 +106,7 @@ public static IntUnaryOperator intSquareOperation() {
* @return binary sum operation
*/
public static LongBinaryOperator longSumOperation() {
throw new ExerciseNotCompletedException();
return Long::sum;
}

/**
Expand All @@ -114,7 +115,7 @@ public static LongBinaryOperator longSumOperation() {
* @return string to int converter
*/
public static ToIntFunction<String> stringToIntConverter() {
throw new ExerciseNotCompletedException();
return Integer::parseInt;
}

/**
Expand All @@ -125,7 +126,7 @@ public static ToIntFunction<String> stringToIntConverter() {
* @return a function supplier
*/
public static Supplier<IntUnaryOperator> nMultiplyFunctionSupplier(int n) {
throw new ExerciseNotCompletedException();
return () -> x -> n * x;
}

/**
Expand All @@ -134,7 +135,7 @@ public static Supplier<IntUnaryOperator> nMultiplyFunctionSupplier(int n) {
* @return function that composes functions with trim() function
*/
public static UnaryOperator<Function<String, String>> composeWithTrimFunction() {
throw new ExerciseNotCompletedException();
return strFunction -> strFunction.compose(String::trim);
}

/**
Expand All @@ -145,7 +146,11 @@ public static UnaryOperator<Function<String, String>> composeWithTrimFunction()
* @return a thread supplier
*/
public static Supplier<Thread> runningThreadSupplier(Runnable runnable) {
throw new ExerciseNotCompletedException();
return () -> {
Thread t = new Thread(runnable);
t.start();
return t;
};
}

/**
Expand All @@ -154,7 +159,7 @@ public static Supplier<Thread> runningThreadSupplier(Runnable runnable) {
* @return a runnable consumer
*/
public static Consumer<Runnable> newThreadRunnableConsumer() {
throw new ExerciseNotCompletedException();
return runnable -> new Thread(runnable).start();
}

/**
Expand All @@ -164,7 +169,11 @@ public static Consumer<Runnable> newThreadRunnableConsumer() {
* @return a function that transforms runnable into a thread supplier
*/
public static Function<Runnable, Supplier<Thread>> runnableToThreadSupplierFunction() {
throw new ExerciseNotCompletedException();
return runnable -> () -> {
Thread t = new Thread(runnable);
t.start();
return t;
};
}

/**
Expand All @@ -177,7 +186,7 @@ public static Function<Runnable, Supplier<Thread>> runnableToThreadSupplierFunct
* @return a binary function that receiver predicate and function and compose them to create a new function
*/
public static BiFunction<IntUnaryOperator, IntPredicate, IntUnaryOperator> functionToConditionalFunction() {
throw new ExerciseNotCompletedException();
return (intFunction, intCondition) -> intParam -> intCondition.test(intParam) ? intFunction.applyAsInt(intParam) : intParam;
}

/**
Expand All @@ -188,7 +197,7 @@ public static BiFunction<IntUnaryOperator, IntPredicate, IntUnaryOperator> funct
* @return a high-order function that fetches a function from a function map by a given name or returns identity()
*/
public static BiFunction<Map<String, IntUnaryOperator>, String, IntUnaryOperator> functionLoader() {
throw new ExerciseNotCompletedException();
return (map, functionName) -> map.getOrDefault(functionName, IntUnaryOperator.identity());
}

/**
Expand All @@ -206,7 +215,7 @@ public static BiFunction<Map<String, IntUnaryOperator>, String, IntUnaryOperator
* @return a comparator instance
*/
public static <T, U extends Comparable<? super U>> Comparator<T> comparing(Function<? super T, ? extends U> mapper) {
throw new ExerciseNotCompletedException();
return Comparator.comparing(mapper);
}

/**
Expand All @@ -226,7 +235,12 @@ public static <T, U extends Comparable<? super U>> Comparator<T> comparing(Funct
*/
public static <T, U extends Comparable<? super U>> Comparator<T> thenComparing(
Comparator<? super T> comparator, Function<? super T, ? extends U> mapper) {
throw new ExerciseNotCompletedException();

return (o1, o2) -> {
int result = comparator.compare(o1, o2);
return result != 0 ? result
: mapper.apply(o1).compareTo(mapper.apply(o2));
};
}

/**
Expand All @@ -235,7 +249,7 @@ public static <T, U extends Comparable<? super U>> Comparator<T> thenComparing(
* @return a supplier instance
*/
public static Supplier<Supplier<Supplier<String>>> trickyWellDoneSupplier() {
throw new ExerciseNotCompletedException();
return () -> () -> () -> "WELL DONE!";
}
}