#18: DeadProc, ConstFunc, IterableAsBooleans

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

@@ -0,0 +1,59 @@
+/**
+ * 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 always returns the same result
+ *
+ * <p>There is no thread-safety guarantee.
+ *
+ * @author Yegor Bugayenko ([email protected])
+ * @version $Id$
+ * @param <X> Type of input
+ * @param <Y> Type of output
+ * @since 0.1
+ */
+public final class ConstFunc<X, Y> implements Func<X, Y> {
+
+    /**
+     * The result to return.
+     */
+    private final Y result;
+
+    /**
+     * Ctor.
+     * @param rslt What to return
+     */
+    public ConstFunc(final Y rslt) {
+        this.result = rslt;
+    }
+
+    @Override
+    public Y apply(final X input) {
+        return this.result;
+    }
+
+}

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

@@ -0,0 +1,45 @@
+/**
+ * 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.Proc;
+
+/**
+ * Proc that does nothing.
+ *
+ * <p>There is no thread-safety guarantee.
+ *
+ * @author Yegor Bugayenko ([email protected])
+ * @version $Id$
+ * @param <T> Type of items
+ * @since 0.1
+ */
+public final class DeadProc<T> implements Proc<T> {
+
+    @Override
+    public void apply(final T input) {
+        // nothing to do
+    }
+
+}

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

@@ -28,7 +28,7 @@
 import org.cactoos.Proc;
 
 /**
- * Consumer that is a func that returns {@code boolean}.
+ * Proc that is a {@link Func} that returns {@code boolean}.
  *
  * <p>You may need this class when you iterate a collection, for example:</p>
  *

src/main/java/org/cactoos/list/AllOf.java

@@ -40,6 +40,15 @@
  *   )
  * ).asValue();</pre>
  *
+ * <p>Or even more compact, through {@link IterableAsBooleans}:</p>
+ *
+ * <pre> new AllOf(
+ *   new IterableAsBooleans&lt;String&gt;(
+ *     Arrays.asList("hello", "world"),
+ *     i -> System.out.println(i)
+ *   )
+ * ).asValue();</pre>
+ *
  * <p>There is no thread-safety guarantee.
  *
  * @author Yegor Bugayenko ([email protected])

src/main/java/org/cactoos/list/IterableAsBooleans.java

@@ -0,0 +1,70 @@
+/**
+ * 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.list;
+
+import java.util.Iterator;
+import org.cactoos.Proc;
+import org.cactoos.func.ProcAsFunc;
+
+/**
+ * Iterable into booleans.
+ *
+ * <p>There is no thread-safety guarantee.
+ *
+ * @author Yegor Bugayenko ([email protected])
+ * @version $Id$
+ * @param <X> Type of source item
+ * @since 0.1
+ */
+public final class IterableAsBooleans<X> implements Iterable<Boolean> {
+
+    /**
+     * Iterable.
+     */
+    private final Iterable<X> iterable;
+
+    /**
+     * Proc.
+     */
+    private final Proc<X> proc;
+
+    /**
+     * Ctor.
+     * @param src Source iterable
+     * @param prc Func
+     */
+    public IterableAsBooleans(final Iterable<X> src, final Proc<X> prc) {
+        this.iterable = src;
+        this.proc = prc;
+    }
+
+    @Override
+    public Iterator<Boolean> iterator() {
+        return new TransformedIterator<>(
+            this.iterable.iterator(),
+            new ProcAsFunc<X>(this.proc)
+        );
+    }
+
+}

src/test/java/org/cactoos/list/AllOfTest.java

@@ -23,6 +23,7 @@
  */
 package org.cactoos.list;
 
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import org.cactoos.func.ProcAsFunc;
@@ -58,4 +59,24 @@ public void iteratesList() {
         );
     }
 
+    /**
+     * AllOf can test all items in the list.
+     */
+    @Test
+    public void iteratesEmptyList() {
+        final List<String> list = new LinkedList<>();
+        MatcherAssert.assertThat(
+            new AllOf(
+                new IterableAsBooleans<String>(
+                    Collections.emptyList(),
+                    list::add
+                )
+            ).asValue(),
+            Matchers.allOf(
+                Matchers.equalTo(true),
+                Matchers.equalTo(list.isEmpty())
+            )
+        );
+    }
+
 }