[01] Show orthoginality to factory patterns

Nicolai Parlog · Nicolai Parlog · commit 09c4e1d14984 · 2018-09-24T15:16:05.000+02:00
diff --git a/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/Main.java b/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/Main.java
@@ -6,6 +6,7 @@
  *  - named constructors
  *  - instance-control
  *  - type-control
+ *  - not factory pattern
  */
 
 public class Main {
diff --git a/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/Rectangle.java b/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/Rectangle.java
@@ -1,8 +1,12 @@
 package org.codefx.demo.effective_java._01_static_factory_methods;
 
+import org.codefx.demo.effective_java._01_static_factory_methods.not_factory_pattern.Shape;
+
 import static org.codefx.demo.effective_java._01_static_factory_methods.Point.ofXY;
 
-public class Rectangle {
+// NOTE not factory pattern:
+//   It only implements `Shape`, so the code in the package not_factory_pattern compiles
+public class Rectangle implements Shape {
 
 	protected final Point lowerLeft, upperRight;
 
diff --git a/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/not_factory_pattern/GrowingRectangleFactory.java b/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/not_factory_pattern/GrowingRectangleFactory.java
@@ -0,0 +1,29 @@
+package org.codefx.demo.effective_java._01_static_factory_methods.not_factory_pattern;
+
+import org.codefx.demo.effective_java._01_static_factory_methods.Point;
+import org.codefx.demo.effective_java._01_static_factory_methods.Rectangle;
+
+// NOTE not factory pattern:
+//   This is an implementation of the abstract factory pattern
+//   (https://en.wikipedia.org/wiki/Abstract_factory_pattern)
+public class GrowingRectangleFactory implements ShapeFactory {
+
+	private Point lowerLeft;
+	private Point upperRight;
+
+	public GrowingRectangleFactory(Point lowerLeft, Point upperRight) {
+		this.lowerLeft = lowerLeft;
+		this.upperRight = upperRight;
+	}
+
+	@Override
+	public Shape createShape() {
+		upperRight = Point.ofXY(upperRight.x() + 1, upperRight.y() + 1);
+		// NOTE not factory pattern:
+		//   Static factory methods are no replacement for abstract factory pattern or factory method pattern.
+		//   In fact, they don't interact with it at all except that you call a static factory method instead
+		//   of a constructor.
+		return Rectangle.fromLowerLeftToUpperRight(lowerLeft, upperRight);
+	}
+
+}
diff --git a/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/not_factory_pattern/Shape.java b/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/not_factory_pattern/Shape.java
@@ -0,0 +1,3 @@
+package org.codefx.demo.effective_java._01_static_factory_methods.not_factory_pattern;
+
+public interface Shape { }
diff --git a/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/not_factory_pattern/ShapeFactory.java b/src/main/java/org/codefx/demo/effective_java/_01_static_factory_methods/not_factory_pattern/ShapeFactory.java
@@ -0,0 +1,7 @@
+package org.codefx.demo.effective_java._01_static_factory_methods.not_factory_pattern;
+
+public interface ShapeFactory {
+
+	public Shape createShape();
+
+}

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+package org.codefx.demo.effective_java._01_static_factory_methods.not_factory_pattern;`
	`2`	`+`
	`3`	`+public interface Shape { }`