Chain of Responsibility design pattern - BONUS EXAMPLE - logger application

premaseem · premaseem · commit fb2d5e3e6f1f · 2018-03-07T10:59:46.000-06:00
diff --git a/patternBonus/src/com/premaseem/chainOfResponsibility/loggerProgram/ClientFileForLoggerProgram.java b/patternBonus/src/com/premaseem/chainOfResponsibility/loggerProgram/ClientFileForLoggerProgram.java
@@ -0,0 +1,62 @@
+package com.premaseem.chainOfResponsibility.loggerProgram;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class ClientFileForLoggerProgram {
+
+	public static void main(String[] args) {
+
+		System.out.println("Welcome to Logger program designed using Chain of Responsibility ");
+		Scanner scan = new Scanner(System.in);
+		LogHandler logHandler;
+		LogHandler allLogLevelHandler = new AllLogLevelHandler();
+		LogHandler debugLogHandler = new DebugLogHandler();
+		LogHandler errorLogHandler = new ErrorLogHandler();
+		LogHandler fatalLogHandler = new FatalLogHandler();
+		LogHandler criticalLogHandler = new CriticalLogHandler();
+
+		// Setting up the chain
+		allLogLevelHandler.setNextHandler(debugLogHandler);
+		debugLogHandler.setNextHandler(errorLogHandler);
+		errorLogHandler.setNextHandler(fatalLogHandler);
+		fatalLogHandler.setNextHandler(criticalLogHandler);
+
+		// Log level priority, high rank covers all below handlers
+		List<LogHandler> logHandlers = new ArrayList<LogHandler>(10);
+		logHandlers.add(0,allLogLevelHandler);
+		logHandlers.add(1,debugLogHandler);
+        logHandlers.add(2,errorLogHandler);
+        logHandlers.add(3,fatalLogHandler);
+        logHandlers.add(4,criticalLogHandler);
+
+		String repeatRunFlag = "y";
+		while (!repeatRunFlag.equalsIgnoreCase("no")) {
+			System.out.println("Please enter message to be logged ");
+			String message = scan.next();
+			System.out.println("Please choose the level from 1 to 5 for logging ");
+			System.out.println("INFO(5),		DEBUG(4),		ERROR(3),		FATAL(2),		CRITICAL(1)");
+			try{
+			int choice = scan.nextInt();
+				logHandler = logHandlers.get(choice);
+			}catch (Exception e){
+				logHandler = logHandlers.get(0);
+			}
+
+			logHandler.handler(message);
+
+			System.out.println("=============================");
+
+			System.out.println("Press No to Exit and any other character to repeat ....  ");
+			try {
+				repeatRunFlag = scan.next();
+			} catch (Exception e) {
+				repeatRunFlag = "n";
+			}
+		}
+
+		System.out.println("\n $$$$$$$$$$$$$$$$$$$$  Thanks by Prem Aseem $$$$$$$$$$$$$$$$$$$$$$ \n ");
+		System.out.println("\n $$$$$$$$$$$$$$$$$$$$$  www.premaseem.me  $$$$$$$$$$$$$$$$$$$$$$ \n ");
+	}
+}
diff --git a/patternBonus/src/com/premaseem/chainOfResponsibility/loggerProgram/LogHandler.java b/patternBonus/src/com/premaseem/chainOfResponsibility/loggerProgram/LogHandler.java
@@ -0,0 +1,51 @@
+package com.premaseem.chainOfResponsibility.loggerProgram;
+
+public abstract class LogHandler {
+
+	
+	public enum LOG_LEVEL {
+		INFO(5),
+		DEBUG(4),
+		ERROR(3),
+		FATAL(2),
+		CRITICAL(1);
+		
+		Integer priority =1;
+		 LOG_LEVEL(int priorityLevel){
+			 priority = priorityLevel;
+		}
+	}
+	
+	LogHandler nextHandler = null;
+
+	public void setNextHandler(LogHandler nextHandler) {
+		this.nextHandler = nextHandler;
+	}
+
+	public void handler(String message) {
+			System.out.printf(" %s console is printing message = %S \n " , this.getClass().getSimpleName(), message );
+		if(nextHandler !=null){
+			nextHandler.handler(message);
+		}
+	}
+}
+
+class AllLogLevelHandler extends LogHandler{
+	
+}
+
+class DebugLogHandler extends LogHandler{
+	
+}
+
+class ErrorLogHandler extends LogHandler{
+	
+}
+
+class FatalLogHandler extends LogHandler{
+	
+}
+
+class CriticalLogHandler extends LogHandler{
+	
+}
