Add Strict for Scalar

src/main/java/org/cactoos/scalar/Strict.java

@@ -0,0 +1,64 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2024 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cactoos.scalar;
+
+import org.cactoos.Func;
+import org.cactoos.Scalar;
+import org.cactoos.func.FuncOf;
+
+/**
+ * Validates the given {@code origin} against the specified {@code rule}.
+ * If the validation fails, the {@code exception} is thrown.
+ *
+ * @param <T> Element type.
+ *
+ * @since 0.56
+ */
+public final class Strict<T> extends ScalarEnvelope<T> {
+
+    /**
+     * Ctor.
+     *
+     * @param origin The value to test againts the {@code rule}.
+     * @param rule The rule, that validates {@code origin}.
+     * @param exception The exception, that is thrown if validation fails.
+     */
+    public Strict(
+        final Scalar<T> origin,
+        final Func<Scalar<T>, Scalar<Boolean>> rule,
+        final Func<Scalar<T>, Exception> exception
+    ) {
+        super(
+            new Mapped<>(
+                new FuncOf<>(origin),
+                new ThrowsOnFalse(
+                    new Flattened<>(
+                        new ScalarOf<>(rule, origin)
+                    ),
+                    new ScalarOf<>(exception, origin)
+                )
+            )
+        );
+    }
+}

src/test/java/org/cactoos/scalar/StrictTest.java

@@ -0,0 +1,64 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2024 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cactoos.scalar;
+
+import org.cactoos.func.FuncOf;
+import org.hamcrest.core.IsEqual;
+import org.junit.Test;
+import org.llorllale.cactoos.matchers.Assertion;
+import org.llorllale.cactoos.matchers.Throws;
+
+/**
+ * Test case for {@link Strict}.
+ *
+ * @since 0.56
+ */
+public final class StrictTest {
+
+    @Test
+    public void throwsExceptionOnFailure() {
+        new Assertion<>(
+            "Must throw the provided exception on rule failure",
+            new Strict<>(
+                new False(),
+                value -> new Equals<>(value, new True()),
+                new FuncOf<>(() -> new IllegalArgumentException("not a true"))
+            ),
+            new Throws<>("not a true", IllegalArgumentException.class)
+        ).affirm();
+    }
+
+    @Test
+    public void returnsIncapsulatedValue() throws Exception {
+        new Assertion<>(
+            "Must return the original value on rule match",
+            new Strict<>(
+                () -> 123,
+                value -> new Equals<>(value, () -> 123),
+                new FuncOf<>(() -> new IllegalArgumentException("unexpected"))
+            ).value(),
+            new IsEqual<>(123)
+        ).affirm();
+    }
+}