#146: RepeatedFunc

src/main/java/org/cactoos/func/RepeatedFunc.java

@@ -0,0 +1,73 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 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.func;
+
+import org.cactoos.Func;
+
+/**
+ * Func that repeats its calculation a few times before
+ * returning the last result.
+ *
+ * @author Yegor Bugayenko (yegor256@gmail.com)
+ * @version $Id$
+ * @param <X> Type of input
+ * @param <Y> Type of output
+ * @since 0.6
+ */
+public final class RepeatedFunc<X, Y> implements Func<X, Y> {
+
+    /**
+     * Original func.
+     */
+    private final Func<X, Y> func;
+
+    /**
+     * How many times to run.
+     */
+    private final int times;
+
+    /**
+     * Ctor.
+     *
+     * <p>If {@code max} is equal or less than zero {@link #apply(Object)}
+     * will return {@code null}.</p>
+     *
+     * @param fnc Func original
+     * @param max How many times
+     */
+    public RepeatedFunc(final Func<X, Y> fnc, final int max) {
+        this.func = fnc;
+        this.times = max;
+    }
+
+    @Override
+    public Y apply(final X input) throws Exception {
+        Y result = null;
+        for (int idx = 0; idx < this.times; ++idx) {
+            result = this.func.apply(input);
+        }
+        return result;
+    }
+
+}

src/main/java/org/cactoos/func/StickyFunc.java

@@ -31,12 +31,16 @@
  * Func that caches previously calculated values and doesn't
  * recalculate again.
  *
+ * <p>This {@link Func} decorator technically is an in-memory
+ * cache.</p>
+ *
  * <p>There is no thread-safety guarantee.
  *
  * @author Yegor Bugayenko (yegor256@gmail.com)
  * @version $Id$
  * @param <X> Type of input
  * @param <Y> Type of output
+ * @see StickyScalar
  * @since 0.1
  */
 public final class StickyFunc<X, Y> implements Func<X, Y> {

src/main/java/org/cactoos/func/StickyScalar.java

@@ -29,12 +29,16 @@
 /**
  * Cached version of a Scalar.
  *
+ * <p>This {@link Scalar} decorator technically is an in-memory
+ * cache.</p>
+ *
  * <p>There is no thread-safety guarantee.
  *
  * @author Tim Hinkes (timmeey@timmeey.de)
  * @author Yegor Bugayenko (yegor256@gmail.com)
  * @version $Id$
  * @param <T> Type of result
+ * @see StickyFunc
  * @since 0.3
  */
 public final class StickyScalar<T> implements Scalar<T> {

src/main/java/org/cactoos/io/StickyInput.java

@@ -46,7 +46,7 @@ public final class StickyInput implements Input {
     /**
      * The cache.
      */
-    private final Scalar<InputStream> cache;
+    private final Scalar<byte[]> cache;
 
     /**
      * Ctor.
@@ -62,14 +62,16 @@ public StickyInput(final Input input) {
                         new OutputStreamAsOutput(baos)
                     )
                 ).asValue();
-                return new ByteArrayInputStream(baos.toByteArray());
+                return baos.toByteArray();
             }
         );
     }
 
     @Override
     public InputStream stream() throws IOException {
-        return new IoCheckedScalar<>(this.cache).asValue();
+        return new ByteArrayInputStream(
+            new IoCheckedScalar<>(this.cache).asValue()
+        );
     }
 
 }

src/test/java/org/cactoos/func/RepeatedFuncTest.java

@@ -0,0 +1,54 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 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.func;
+
+import java.security.SecureRandom;
+import org.cactoos.Func;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Test case for {@link RepeatedFunc}.
+ *
+ * @author Yegor Bugayenko (yegor256@gmail.com)
+ * @version $Id$
+ * @since 0.6
+ * @checkstyle JavadocMethodCheck (500 lines)
+ */
+public final class RepeatedFuncTest {
+
+    @Test
+    public void runsFuncMultipleTimes() throws Exception {
+        final Func<Boolean, Integer> func = new RepeatedFunc<>(
+            input -> new SecureRandom().nextInt(),
+            2
+        );
+        MatcherAssert.assertThat(
+            func.apply(true),
+            Matchers.not(Matchers.equalTo(func.apply(true)))
+        );
+    }
+
+}

src/test/java/org/cactoos/io/StickyInputTest.java

@@ -24,9 +24,8 @@
 package org.cactoos.io;
 
 import org.cactoos.func.FuncAsMatcher;
-import org.cactoos.func.ProcAsFunc;
+import org.cactoos.func.RepeatedFunc;
 import org.hamcrest.MatcherAssert;
-import org.hamcrest.Matchers;
 import org.junit.Test;
 
 /**
@@ -43,28 +42,17 @@ public void readsFileContent() {
         MatcherAssert.assertThat(
             "Can't read bytes from a file",
             new StickyInput(
-                new UrlAsInput(
-                    this.getClass().getResource(
-                        "/org/cactoos/io/UrlAsInput.class"
-                    )
+                new ResourceAsInput(
+                    "org/cactoos/large-text.txt"
                 )
             ),
             new FuncAsMatcher<>(
-                new ProcAsFunc<>(
-                    input -> {
-                        MatcherAssert.assertThat(
-                            new InputAsBytes(
-                                new TeeInput(input, new DeadOutput())
-                            ).asBytes().length,
-                            Matchers.greaterThan(0)
-                        );
-                        MatcherAssert.assertThat(
-                            new InputAsBytes(
-                                new TeeInput(input, new DeadOutput())
-                            ).asBytes().length,
-                            Matchers.greaterThan(0)
-                        );
-                    }
+                new RepeatedFunc<>(
+                    input -> new InputAsBytes(
+                        new TeeInput(input, new DeadOutput())
+                    // @checkstyle MagicNumber (1 line)
+                    ).asBytes().length == 73471,
+                    2
                 )
             )
         );