template method added

Author: maciej-nowak

template-method/README.md

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+# template-method
+This is repository of http://androidcode.pl blog. It shows uses of Template method in Android. It is a part of Design Patterns - Template method post in the blog.

template-method/example/Main.java

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+public class Main {
+
+	public static void main() {
+		//check the user choice and set proper RouteFinder
+		RouteFinder routeFinder = new CarRoute();
+
+		//get coordinates of choosen start and destination points
+		Coordinates start = new Coordinates(52.409538, 16.931993); //Poznań
+		Coordinates destination = new Coordinates(52.237049, 21.017532); //Warsaw
+
+		//find route
+		//show progress
+		boolean success = routeFinder.find(start, destination);
+		//hide progress
+		if(success) {
+		    Route route = routeFinder.getRoute();
+		    //show route on map with tips
+		}
+		else {
+		    //show proper message
+		}
+	}
+}

template-method/example/RouteFinder.java

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+public abstract class RouteFinder {
+
+    private Route route = new Route();
+
+    public Route find(Coordinates start, Coordinates destination) {
+        route = new Route();
+        Marker startPoint = Map.getMarker(start);
+        Marker endPoint = Map.getMarker(destination);
+
+        logSearching("Search trace: " + start.toString() + " - " + destination.toString());
+
+        saveSearch(startPoint);
+        saveSearch(destinationPoint);
+
+        List<Marker> trackPoints = getTrackPoints(startPoint, destinationPoint);
+        if(trackPoints.size() > 2) {
+            List<Tip> tips = getRouteTips(trackPoints);
+            route.setTrackPoints(trackPoints);  
+            route.setTips(tips);
+            return true;
+        }
+        else return false;
+    }
+
+    public Route getRoute() {
+        return route;
+    }
+
+    protected abstract List<Marker> getTrackPoints(Marker start, Marker destination);
+    protected abstract List<Tip> getRouteTips(List<Marker> trackPoints);
+
+    protected void saveSearch(Marker point) {
+        //add search to local memory to improve search suggestions
+    }
+
+    protected void logSearching(String text) {
+    	Logger.log(text);
+    }
+
+    //some others operations
+}

template-method/example/controllers/Logger.java

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+public class Logger {
+
+	//some fields
+
+	public static void log(String text) {
+		//log text
+	}
+
+	//other methods
+}

template-method/example/controllers/Map.java

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+public class Map {
+
+	//some fields
+	
+	public static Marker getMarker(Coordinates coordinates) {
+		//get marker from Map data
+		return new Marker("Name", "description", new Coordinates(52.409538, 16.931993), Type.CAR);
+	}
+
+	//other methods
+}

template-method/example/dummy/Coordinates.java

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+public class Coordinates {
+
+	private double latitude;
+	private double longitude;
+
+	public Coordinates(double latitude, double longitude) {
+		this.latitude = latitude;
+		this.longitude = longitude;
+	}
+
+	public double getLatitude() {
+		return latitude;
+	}
+
+	public double getLongitude() {
+		return longitude;
+	}
+}

template-method/example/dummy/Marker.java

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+public class Marker {
+
+	private String name;
+	private String description;
+	private Coordinates coordinates;
+	private Type type;
+	//other fields
+
+	public Marker(String name, String description, Coordinates coordinates, Type type) {
+		this.name = name;
+		this.description = description;
+		this.coordinates = coordinates;
+		this.type = type;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public String getDescription() {
+		return description;
+	}
+
+	public Coordinates getCoordinates() {
+		return coordinates;
+	}
+
+	public Type getType() {
+		return type;
+	}
+
+	public String toString() {
+		return "Marker\n name: " + name + "\n" + "description: " + description + "\n"
+		+ "coordinates: " + coordinates.getLatitude() + ", " + coordinates.getLongitude() + "\n"
+		+ "type: " + type.toString();
+	}
+
+	//other methods
+
+	public enum Type {
+
+		WALK(1),
+		CAR(2),
+		PUBLIC_TRANSPORT(3),
+		TRUCK(4);
+		//more types
+
+		private int type;
+
+		public Type(int type) {
+			this.type = type;
+		}
+
+		public String toString() {
+			switch(type) {
+				case WALK:
+					return "WALK";
+				case CAR:
+					return "CAR";
+				case PUBLIC_TRANSPORT:
+					return "PUBLIC_TRANSPORT";
+				case TRUCK:
+					return "TRUCK";
+				default:
+					return "UNKNOWN";
+			}
+		}
+	}
+}

template-method/example/dummy/Route.java

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+public class Route {
+
+	private List<Marker> markers;
+	private List<Tip> tips;
+	//other fields
+
+	public Route() {
+		markers = new ArrayList();
+		tips = new ArrayList();
+	}
+
+	public void setMarkers(List<Marker> markers) {
+		this.markers = markers;
+	}
+
+	public void setTips(List<Tip> tips) {
+		this.tips = tips;
+	}
+
+	public List<Marker> getMarkers() {
+		return markers;
+	}
+
+	public List<Tip> getTips() {
+		return tips;
+	}
+
+	//other methods
+}

template-method/example/dummy/Tip.java

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+public class Tip {
+
+	private String description;
+	private Date time;
+	private int distance;
+	//other fields
+
+	public Tip(String description, Date time, int distance) {
+		this.description = description;
+		this.time = time;
+		this.distance = distance;
+	}
+
+	public String getDescription() {
+		return description;
+	}
+
+	public Date getStartTime() {
+		return time;
+	}
+
+	public int getDistance() {
+		return distance;
+	}
+
+	//other methods
+}

template-method/example/templates/CarRoute.java

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+public class CarRoute extends RouteFinder {
+
+    @Override
+    protected List<Marker> getTrackPoints(Marker start, Marker destination) {
+        List<Marker> markers = new ArrayList();
+        //find possible roads
+        //add track all track points from the road
+        return markers;
+    }
+
+    @Override
+    protected List<Tip> getRouteTips(List<Marker> trackPoints) {
+        List<Tip> tips = new ArrayList();
+        //add tips for every crossing
+        return tips;
+    }
+}

template-method/example/templates/PublicTransportRoute.java

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+public class PublicTransportRoute extends RouteFinder {
+
+    @Override
+    protected List<Marker> getTrackPoints(Marker start, Marker destination) {
+        List<Marker> markers = new ArrayList();
+        //find the nereast station to start Marker and the nearest station to destination
+        //connect with public transport providers to get possible routes between stations
+        //add walk or car track points between start Marker and start station
+        //add stations to track points
+        //add walk or car track points between end station and destination Marker
+        //add trackpoints from start to nerest station
+        return markers;
+    }
+
+    @Override
+    protected List<Tip> getRouteTips(List<Marker> trackPoints) {
+        List<Tip> tips = new ArrayList();
+        //connect with public transport providers to get schedule
+        //add tips for every station
+        return tips;
+    }
+
+    @Override
+    protected void logSearching(String text) {
+        super.logSearching(text);
+        //and send analytics data to public transport providers
+    }
+
+    @Override
+    protected void saveSearch(Marker point) {
+        //do not save public transport searching
+    }
+}

template-method/pattern/AbstractClass.java

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+public abstract class AbstractClass {
+
+    public void templateMethod() {
+        primitiveOperation1();
+        primitiveOperation2();
+        primitiveOperation3();
+    }
+
+    protected abstract void primitiveOperation2();
+
+    private void primitiveOperation1() {
+        //do something always
+    }
+
+    protected void primitiveOperation3() {
+        //do something optional
+    }
+
+    //some others operations
+}

template-method/pattern/Main.java

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+public class Main {
+
+	public static void main() {
+		AbstractClass object = new ConcreteClass1();
+		object.templateMethod();
+	}
+}

template-method/pattern/templates/ConcreteClass1.java

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+public class ConcreteClass1 extends AbstractClass {
+
+    @Override
+    protected void primitiveOperation2() {
+        //do custom work for ConcreteClass1
+    }
+
+    @Override
+    protected void primitiveOperation3() {
+        //do custom work for ConcreteClass2 by overriding default
+    }
+}

template-method/pattern/templates/ConcreteClass2.java

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+public class ConcreteClass2 extends AbstractClass {
+
+    @Override
+    protected void primitiveOperation2() {
+        //do custom work for ConcreteClass2
+    }
+}