#104 MappedRow

src/main/java/com/vssekorin/cactoosmath/matrix/MappedRow.java

@@ -0,0 +1,71 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2017-2018 Vseslav Sekorin
+ *
+ * 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 NONINFRINGEMENT. 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 com.vssekorin.cactoosmath.matrix;
+
+import com.vssekorin.cactoosmath.Matrix;
+import org.cactoos.Func;
+
+/**
+ * Matrix with mapped row.
+ *
+ * @author Vseslav Sekorin (vssekorin@gmail.com)
+ * @version $Id$
+ * @param <T> Elements type
+ * @since 0.2
+ */
+@SuppressWarnings(
+    {
+        "PMD.CallSuperInConstructor",
+        "PMD.ConstructorOnlyInitializesOrCallOtherConstructors"
+    }
+)
+public final class MappedRow<T> extends MatrixEnvelope<T> {
+
+    /**
+     * Ctor.
+     * @param src Origin matrix
+     * @param number Number of row
+     * @param map Map function
+     */
+    @SuppressWarnings("unchecked")
+    public MappedRow(final Matrix<T> src, final int number,
+        final Func<T, T> map) {
+        super(() -> () -> {
+            final int rows = new NmbRows<>(src).value();
+            final int cols = new NmbColumns<>(src).value();
+            final T[][] result = (T[][]) new Object[rows][cols];
+            final T[][] array = src.asArray();
+            for (int row = 0; row < rows; ++row) {
+                if (row == number) {
+                    for (int col = 0; col < cols; ++col) {
+                        result[row][col] = map.apply(array[row][col]);
+                    }
+                } else {
+                    System.arraycopy(array[row], 0, result[row], 0, cols);
+                }
+            }
+            return result;
+        });
+    }
+}

src/test/java/com/vssekorin/cactoosmath/matrix/MappedRowTest.java

@@ -0,0 +1,64 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2017-2018 Vseslav Sekorin
+ *
+ * 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 NONINFRINGEMENT. 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 com.vssekorin.cactoosmath.matrix;
+
+import org.hamcrest.CoreMatchers;
+import org.hamcrest.MatcherAssert;
+import org.junit.Test;
+
+/**
+ * Test case for {@link MappedRow}.
+ *
+ * @author Vseslav Sekorin (vssekorin@gmail.com)
+ * @version $Id$
+ * @since 0.2
+ * @checkstyle JavadocMethodCheck (500 lines)
+ * @checkstyle MagicNumberCheck (500 lines)
+ */
+public final class MappedRowTest {
+
+    @Test
+    public void asArray() throws Exception {
+        MatcherAssert.assertThat(
+            new MappedRow<>(
+                new MatrixOf<>(
+                    new Integer[][]{
+                        {1, 2, 3},
+                        {4, 5, 6},
+                        {7, 8, 9},
+                    }
+                ),
+                1,
+                inm -> 0
+            ).asArray(),
+            CoreMatchers.equalTo(
+                new Integer[][]{
+                    {1, 2, 3},
+                    {0, 0, 0},
+                    {7, 8, 9},
+                }
+            )
+        );
+    }
+}