Flyweight Design Patterns

com/javadevjournal/design/structural/flyweight/Brush.java

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+package javadevjournal.design.structural.flyweight;
+
+/**
+ *
+ */
+public interface Brush {
+    public void setColor(String color);
+
+    public void draw(String content);
+}

com/javadevjournal/design/structural/flyweight/BrushFactory.java

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+package javadevjournal.design.structural.flyweight;
+
+import java.util.HashMap;
+
+/**
+ * @author Kunwar
+ */
+public class BrushFactory {
+
+    private static final HashMap<String, Brush> brushMap = new HashMap<>();
+
+    public static Brush getThickBrush(String color) {
+        String key = color + "-THICK";
+        Brush brush = brushMap.get(key);
+
+        if (brush != null) {
+            return brush;
+        } else {
+            brush = new ThickBrush();
+            brush.setColor(color);
+            brushMap.put(key, brush);
+        }
+        return brush;
+    }
+
+    public static Brush getThinBrush(String color) {
+        String key = color + "-THIN";
+        Brush brush = brushMap.get(key);
+
+        if (brush != null) {
+            return brush;
+        } else {
+            brush = new ThinBrush();
+            brush.setColor(color);
+            brushMap.put(key, brush);
+        }
+
+        return brush;
+    }
+
+    public static Brush getMediumBrush(String color) {
+        String key = color + "-MEDIUM";
+        Brush brush = brushMap.get(key);
+
+        if (brush != null) {
+            return brush;
+        } else {
+            brush = new MediumBrush();
+            brush.setColor(color);
+            brushMap.put(key, brush);
+        }
+
+        return brush;
+    }
+}

com/javadevjournal/design/structural/flyweight/BrushSize.java

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+package javadevjournal.design.structural.flyweight;
+
+/**
+ * @author Kunwar
+ */
+public enum BrushSize {
+    THIN, MEDIUM, THICK
+}

com/javadevjournal/design/structural/flyweight/FlyweightPatternDemo.java

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+package javadevjournal.design.structural.flyweight;
+
+/**
+ * @author Kunwar
+ */
+public class FlyweightPatternDemo {
+    public static void main(String[] args) {
+        // New thick Red Brush
+        Brush redThickBrush1 = BrushFactory.getThickBrush("RED");
+        redThickBrush1.draw("Hello There !!");
+
+        // Red Brush is shared
+        Brush redThickBrush2 = BrushFactory.getThickBrush("RED");
+        redThickBrush2.draw("Hello There Again !!");
+
+        System.out.println("Hashcode: " + redThickBrush1.hashCode());
+        System.out.println("Hashcode: " + redThickBrush2.hashCode());
+
+        // New thin Blue Brush
+        Brush blueThinBrush1 = BrushFactory.getThinBrush("BLUE");   //created new pen
+        blueThinBrush1.draw("Hello There !!");
+
+        // Blue Brush is shared
+        Brush blueThinBrush2 = BrushFactory.getThinBrush("BLUE");   //created new pen
+        blueThinBrush2.draw("Hello There Again!!");
+
+        System.out.println("Hashcode: " + blueThinBrush1.hashCode());
+        System.out.println("Hashcode: " + blueThinBrush2.hashCode());
+
+        // New MEDIUM Yellow Brush
+        Brush yellowThinBrush1 = BrushFactory.getMediumBrush("YELLOW");   //created new pen
+        yellowThinBrush1.draw("Hello There !!");
+
+        // Yellow brush is shared
+        Brush yellowThinBrush2 = BrushFactory.getMediumBrush("YELLOW");   //created new pen
+        yellowThinBrush2.draw("Hello There Again!!");
+
+        System.out.println("Hashcode: " + yellowThinBrush1.hashCode());
+        System.out.println("Hashcode: " + yellowThinBrush2.hashCode());
+    }
+}

com/javadevjournal/design/structural/flyweight/MediumBrush.java

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+package javadevjournal.design.structural.flyweight;
+
+/**
+ * @author Kunwar
+ */
+public class MediumBrush implements Brush {
+
+    /*
+      intrinsic state - shareable
+     */
+    final BrushSize brushSize = BrushSize.MEDIUM;
+
+    /*
+      extrinsic state - supplied by client
+     */
+    private String color = null;
+
+    public void setColor(String color) {
+        this.color = color;
+    }
+
+    @Override
+    public void draw(String content) {
+        System.out.println("Drawing MEDIUM '" + content + "' in color : " + color);
+    }
+}

com/javadevjournal/design/structural/flyweight/ThickBrush.java

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+package javadevjournal.design.structural.flyweight;
+
+/**
+ * @author Kunwar
+ */
+public class ThickBrush implements Brush {
+    /*
+      intrinsic state - shareable
+     */
+    final BrushSize brushSize = BrushSize.THICK;
+
+    /*
+      extrinsic state - supplied by client
+     */
+    private String color = null;
+
+    public void setColor(String color) {
+        this.color = color;
+    }
+
+    @Override
+    public void draw(String content) {
+        System.out.println("Drawing THICK '" + content + "' in color : " + color);
+    }
+}

com/javadevjournal/design/structural/flyweight/ThinBrush.java

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+package javadevjournal.design.structural.flyweight;
+
+/**
+ * @author Kunwar
+ */
+public class ThinBrush implements Brush {
+
+    /*
+      intrinsic state - shareable
+     */
+    final BrushSize brushSize = BrushSize.THIN;
+
+    /*
+      extrinsic state - supplied by client
+     */
+    private String color = null;
+
+    public void setColor(String color) {
+        this.color = color;
+    }
+
+    @Override
+    public void draw(String content) {
+        System.out.println("Drawing THIN '" + content + "' in color : " + color);
+    }
+}