#297 Matrix element

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

@@ -0,0 +1,46 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2022 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 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 com.vssekorin.cactoosmath.matrix;
+
+import com.vssekorin.cactoosmath.Matrix;
+import org.cactoos.scalar.ScalarEnvelope;
+
+/**
+ * The element of a matrix.
+ *
+ * @param <T> Type of element.
+ * @since 0.2
+ */
+public final class Element<T> extends ScalarEnvelope<T> {
+
+    /**
+     * Ctor.
+     * @param matrix Matrix
+     * @param row Row
+     * @param column Column
+     */
+    public Element(final Matrix<T> matrix, final int row, final int column) {
+        super(() -> matrix.asArray()[row][column]);
+    }
+}

src/test/java/com/vssekorin/cactoosmath/ElementTest.java

@@ -0,0 +1,58 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2022 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 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 com.vssekorin.cactoosmath;
+
+import com.vssekorin.cactoosmath.matrix.Element;
+import com.vssekorin.cactoosmath.matrix.MatrixOf;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Test case for {@link Element}.
+ *
+ * @since 0.2
+ * @checkstyle JavadocMethodCheck (500 lines)
+ * @checkstyle MagicNumberCheck (500 lines)
+ */
+public final class ElementTest {
+
+    @Test
+    public void value() throws Exception {
+        MatcherAssert.assertThat(
+            "Must return element by index [1, 1]",
+            new Element<>(
+                new MatrixOf<>(
+                    new Integer[][]{
+                        {5, 7, 4},
+                        {-4, 6, 0},
+                        {2, 0, 3},
+                    }
+                ),
+                1, 1
+            ).value(),
+            Matchers.equalTo(6)
+        );
+    }
+}