Add Result.tryPeek (#14)

Signed-off-by: David Greven <[email protected]> Signed-off-by: Sebastian Becker <[email protected]>
carbynestack · Nov 16, 2021 · 3c6c68c · 3c6c68c
1 parent 4d8d588
commit 3c6c68c
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diff --git a/common-testing/src/test/java/io/carbynestack/common/result/FailureTest.java b/common-testing/src/test/java/io/carbynestack/common/result/FailureTest.java
@@ -11,6 +11,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 
+import java.io.IOException;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -70,6 +71,28 @@ void peekNullPointerException() {
                 .isExactlyInstanceOf(NullPointerException.class);
     }
 
+    @Test
+    void tryPeek() {
+        AtomicInteger output = new AtomicInteger(-1);
+        result.tryPeek(output::set, reason * 2);
+        assertThat(output).hasValue(-1);
+    }
+
+    @Test
+    void tryPeekWithException() {
+        Result<Integer, Integer> res = result.tryPeek(v -> {
+            throw new IOException("-11");
+        }, reason * 2);
+        assertThat(res).isFailure();
+        assertThat(res).hasReason(reason);
+    }
+
+    @Test
+    void tryPeekNullPointerException() {
+        assertThatThrownBy(() -> result.tryPeek(null, reason * 2))
+                .isExactlyInstanceOf(NullPointerException.class);
+    }
+
     @Test
     void recover() {
         assertThat(result.recover(r -> r * 2)).hasValue(42);

diff --git a/common-testing/src/test/java/io/carbynestack/common/result/SuccessTest.java b/common-testing/src/test/java/io/carbynestack/common/result/SuccessTest.java
@@ -11,6 +11,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 
+import java.io.IOException;
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
@@ -71,6 +72,29 @@ void peekNullPointerException() {
                 .isExactlyInstanceOf(NullPointerException.class);
     }
 
+    @Test
+    void tryPeek() {
+        AtomicInteger output = new AtomicInteger(-1);
+        result.tryPeek(output::set, -11);
+        assertThat(output).hasValue(value);
+    }
+
+    @Test
+    void tryPeekWithException() {
+        int reason = -11;
+        Result<Integer, Integer> res = result.tryPeek(v -> {
+            throw new IOException("-11");
+        }, reason);
+        assertThat(res).isFailure();
+        assertThat(res).hasReason(reason);
+    }
+
+    @Test
+    void tryPeekNullPointerException() {
+        assertThatThrownBy(() -> result.tryPeek(null, -11))
+                .isExactlyInstanceOf(NullPointerException.class);
+    }
+
     @Test
     void recover() {
         assertThat(result.recover(identity())).hasValue(value);

diff --git a/common-types/src/main/java/io/carbynestack/common/result/Failure.java b/common-types/src/main/java/io/carbynestack/common/result/Failure.java
@@ -7,6 +7,7 @@
 package io.carbynestack.common.result;
 
 import io.carbynestack.common.Generated;
+import io.carbynestack.common.function.AnyThrowingConsumer;
 
 import java.util.Objects;
 import java.util.Optional;
@@ -104,6 +105,24 @@ public Result<S, F> peek(Consumer<? super S> consumer) {
         return this;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param consumer the consumer of {@link Success#value()}
+     * @param reason   the failure reason in case of the consumer throwing
+     *                 a {@code Throwable}
+     * @return {@code this}
+     * @throws NullPointerException if the consumer is {@code null}
+     * @version JDK 8
+     * @see #map(Function)
+     * @since 0.1.0
+     */
+    @Override
+    public Result<S, F> tryPeek(AnyThrowingConsumer<? super S> consumer, F reason) {
+        requireNonNull(consumer);
+        return this;
+    }
+
     /**
      * {@inheritDoc}
      *

diff --git a/common-types/src/main/java/io/carbynestack/common/result/Result.java b/common-types/src/main/java/io/carbynestack/common/result/Result.java
@@ -7,6 +7,7 @@
 package io.carbynestack.common.result;
 
 import io.carbynestack.common.CsFailureReason;
+import io.carbynestack.common.function.AnyThrowingConsumer;
 import io.carbynestack.common.function.AnyThrowingSupplier;
 import io.carbynestack.common.function.ThrowingSupplier;
 
@@ -123,6 +124,24 @@ default boolean isFailure() {
      */
     Result<S, F> peek(Consumer<? super S> consumer);
 
+    /**
+     * If the {@code Result} is a {@link Success}, invokes the provided
+     * consumer with the {@link Success#value()}. Otherwise, the
+     * {@link Failure} is returned.
+     *
+     * <p>In case the consumer throws a {@link Throwable} the failure reason
+     * is returned as a {@code Failure}.<br>
+     *
+     * @param consumer the consumer of {@link Success#value()}
+     * @param reason   the failure reason in case of the consumer throwing
+     *                 a {@code Throwable}
+     * @return {@code this}
+     * @throws NullPointerException if the consumer is {@code null}
+     * @see #map(Function)
+     * @since 0.1.0
+     */
+    Result<S, F> tryPeek(AnyThrowingConsumer<? super S> consumer, F reason);
+
     /**
      * If the {@code Result} is a {@link Failure}, returns the result of
      * applying the given mapping function to the {@link Failure#reason()}.

diff --git a/common-types/src/main/java/io/carbynestack/common/result/Success.java b/common-types/src/main/java/io/carbynestack/common/result/Success.java
@@ -7,6 +7,7 @@
 package io.carbynestack.common.result;
 
 import io.carbynestack.common.Generated;
+import io.carbynestack.common.function.AnyThrowingConsumer;
 
 import java.util.Objects;
 import java.util.Optional;
@@ -105,6 +106,29 @@ public Result<S, F> peek(Consumer<? super S> consumer) {
         return this;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param consumer the consumer of {@link Success#value()}
+     * @param reason   the failure reason in case of the consumer throwing
+     *                 a {@code Throwable}
+     * @return {@code this}
+     * @throws NullPointerException if the consumer is {@code null}
+     * @version JDK 8
+     * @see #map(Function)
+     * @since 0.1.0
+     */
+    @Override
+    public Result<S, F> tryPeek(AnyThrowingConsumer<? super S> consumer, F reason) {
+        requireNonNull(consumer);
+        try {
+            consumer.accept(this.value());
+            return this;
+        } catch (Throwable throwable) {
+            return new Failure<>(reason);
+        }
+    }
+
     /**
      * {@inheritDoc}
      *

diff --git a/common-types/src/main/java17/io/carbynestack/common/result/Failure.java b/common-types/src/main/java17/io/carbynestack/common/result/Failure.java
@@ -6,6 +6,8 @@
  */
 package io.carbynestack.common.result;
 
+import io.carbynestack.common.function.AnyThrowingConsumer;
+
 import java.util.Optional;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -74,6 +76,24 @@ public Result<S, F> peek(Consumer<? super S> consumer) {
         return this;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param consumer the consumer of {@link Success#value()}
+     * @param reason   the failure reason in case of the consumer throwing
+     *                 a {@code Throwable}
+     * @return {@code this}
+     * @throws NullPointerException if the consumer is {@code null}
+     * @version JDK 17
+     * @see #map(Function)
+     * @since 0.1.0
+     */
+    @Override
+    public Result<S, F> tryPeek(AnyThrowingConsumer<? super S> consumer, F reason) {
+        requireNonNull(consumer);
+        return this;
+    }
+
     /**
      * {@inheritDoc}
      *

diff --git a/common-types/src/main/java17/io/carbynestack/common/result/Result.java b/common-types/src/main/java17/io/carbynestack/common/result/Result.java
@@ -7,6 +7,7 @@
 package io.carbynestack.common.result;
 
 import io.carbynestack.common.CsFailureReason;
+import io.carbynestack.common.function.AnyThrowingConsumer;
 import io.carbynestack.common.function.AnyThrowingSupplier;
 import io.carbynestack.common.function.ThrowingSupplier;
 
@@ -123,6 +124,24 @@ default boolean isFailure() {
      */
     Result<S, F> peek(Consumer<? super S> consumer);
 
+    /**
+     * If the {@code Result} is a {@link Success}, invokes the provided
+     * consumer with the {@link Success#value()}. Otherwise, the
+     * {@link Failure} is returned.
+     *
+     * <p>In case the consumer throws a {@link Throwable} the failure reason
+     * is returned as a {@code Failure}.<br>
+     *
+     * @param consumer the consumer of {@link Success#value()}
+     * @param reason   the failure reason in case of the consumer throwing
+     *                 a {@code Throwable}
+     * @return {@code this}
+     * @throws NullPointerException if the consumer is {@code null}
+     * @see #map(Function)
+     * @since 0.1.0
+     */
+    Result<S, F> tryPeek(AnyThrowingConsumer<? super S> consumer, F reason);
+
     /**
      * If the {@code Result} is a {@link Failure}, returns the result of
      * applying the given mapping function to the {@link Failure#reason()}.

diff --git a/common-types/src/main/java17/io/carbynestack/common/result/Success.java b/common-types/src/main/java17/io/carbynestack/common/result/Success.java
@@ -6,6 +6,8 @@
  */
 package io.carbynestack.common.result;
 
+import io.carbynestack.common.function.AnyThrowingConsumer;
+
 import java.util.Optional;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -75,6 +77,29 @@ public Result<S, F> peek(Consumer<? super S> consumer) {
         return this;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param consumer the consumer of {@link Success#value()}
+     * @param reason   the failure reason in case of the consumer throwing
+     *                 a {@code Throwable}
+     * @return {@code this}
+     * @throws NullPointerException if the consumer is {@code null}
+     * @version JDK 17
+     * @see #map(Function)
+     * @since 0.1.0
+     */
+    @Override
+    public Result<S, F> tryPeek(AnyThrowingConsumer<? super S> consumer, F reason) {
+        requireNonNull(consumer);
+        try {
+            consumer.accept(this.value());
+            return this;
+        } catch (Throwable throwable) {
+            return new Failure<>(reason);
+        }
+    }
+
     /**
      * {@inheritDoc}
      *

diff --git a/common-types/src/test/java/io/carbynestack/common/result/ResultTest.java b/common-types/src/test/java/io/carbynestack/common/result/ResultTest.java
@@ -75,6 +75,17 @@ void result() {
         assertThat(res.stream().toList()).isEmpty();
     }
 
+    @Test
+    void tryPeek() {
+        assertThat(new Success<>(12)
+                .tryPeek(System.out::println, -1)
+                .tryPeek(v -> {
+                    throw new IOException();
+                }, -1)
+                .tryPeek(System.out::println, -1)
+                .isFailure()).isTrue();
+    }
+
     @Test
     void of() {
         assertThat(Result.of(() -> 12).isSuccess()).isTrue();