introduced BinaryExpression

Author: Torsten-Mumme

src/main/java/net/itarray/automotion/validation/properties/BinaryExpression.java

@@ -0,0 +1,34 @@
+package net.itarray.automotion.validation.properties;
+
+import net.itarray.automotion.internal.geometry.Direction;
+import net.itarray.automotion.internal.properties.Context;
+
+import java.util.function.BiFunction;
+
+public class BinaryExpression<L, R, T> implements Expression<T> {
+
+    private final Expression<L> left;
+    private final Expression<R> right;
+    private final BiFunction<L, R, T> operation;
+    private String descriptionFormat;
+
+    public BinaryExpression(Expression<L> left, Expression<R> right, BiFunction<L, R, T> operation, String descriptionFormat) {
+        this.left = left;
+        this.right = right;
+        this.operation = operation;
+        this.descriptionFormat = descriptionFormat;
+    }
+
+    @Override
+    public T evaluateIn(Context context, Direction direction) {
+        return operation.apply(left.evaluateIn(context, direction), right.evaluateIn(context, direction));
+    }
+
+    @Override
+    public String getDescription(Context context, Direction direction) {
+        return String.format(
+                descriptionFormat,
+                left.getDescription(context, direction),
+                right.getDescription(context, direction));
+    }
+}

src/test/java/net/itarray/automotion/tests/properties/BinaryExpressionTest.java

@@ -0,0 +1,36 @@
+package net.itarray.automotion.tests.properties;
+
+import net.itarray.automotion.internal.geometry.Direction;
+import net.itarray.automotion.internal.geometry.Scalar;
+import net.itarray.automotion.internal.properties.PixelConstant;
+import net.itarray.automotion.validation.properties.BinaryExpression;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BinaryExpressionTest {
+
+    private BinaryExpression<Scalar, Scalar, Boolean> expression;
+
+    @Before
+    public void setUp() {
+        expression = new BinaryExpression<>(
+                new PixelConstant(new Scalar(17)),
+                new PixelConstant(new Scalar(16)),
+                Scalar::isLessOrEqualTo,
+                "%s to be less or equal to %s");
+    }
+
+    @Test
+    public void evaluatesToTheValueOfTheOperationAppliedToTheEvaluatedLeftAndRightExpressions() {
+        Boolean result = expression.evaluateIn(new TestContext(), Direction.RIGHT);
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void shouldName() {
+        String description = expression.getDescription(new TestContext(), Direction.RIGHT);
+        assertThat(description).isEqualTo("17px to be less or equal to 16px");
+    }
+}