add logger application

Logger/src/com/paradox/logger/LoggerApplication.java

@@ -0,0 +1,24 @@
+package com.paradox.logger;
+
+import com.paradox.logger.services.LoggerService;
+import com.paradox.logger.services.LogClient;
+
+public class LoggerApplication {
+ public static void main(String[] args) {
+ LogClient logger = new LoggerService();
+ logger.start("1", 1);
+ logger.poll();
+ logger.start("3", 2);
+ logger.poll();
+ logger.end("1", 3);
+ logger.poll();
+ logger.start("2", 3);
+ logger.poll();
+ logger.end("2",4);
+ logger.poll();
+ logger.end("3", 6);
+ logger.poll();
+ logger.poll();
+ logger.poll();
+ }
+}

Logger/src/com/paradox/logger/ProcessComparator.java

@@ -0,0 +1,12 @@
+package com.paradox.logger;
+
+import com.paradox.logger.models.Process;
+
+import java.util.Comparator;
+
+public class ProcessComparator implements Comparator<Process> {
+ @Override
+ public int compare(Process o1, Process o2) {
+ return Long.compare(o1.getStart(), o2.getStart());
+ }
+}

Logger/src/com/paradox/logger/models/Process.java

@@ -0,0 +1,29 @@
+package com.paradox.logger.models;
+
+public class Process {
+ private final String id;
+ private final long start;
+ private long end;
+
+ public Process(String id, long start) {
+ this.id = id;
+ this.start = start;
+ this.end = -1;
+ }
+
+ public String getId() {
+ return id;
+ }
+
+ public long getStart() {
+ return start;
+ }
+
+ public long getEnd() {
+ return end;
+ }
+
+ public void setEnd(long end) {
+ this.end = end;
+ }
+}

Logger/src/com/paradox/logger/services/LogClient.java

@@ -0,0 +1,7 @@
+package com.paradox.logger.services;
+
+public interface LogClient {
+ void start(String processId, long timestamp);
+ void end(String processId, long timestamp);
+ String poll();
+}

Logger/src/com/paradox/logger/services/LoggerService.java

@@ -0,0 +1,42 @@
+package com.paradox.logger.services;
+
+import com.paradox.logger.ProcessComparator;
+import com.paradox.logger.models.Process;
+import com.paradox.logger.services.LogClient;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PriorityQueue;
+
+public class LoggerService implements LogClient {
+ private Map<String, Long> startMap;
+ private PriorityQueue<Process> processQueue;
+
+ public LoggerService() {
+ startMap = new HashMap<>();
+ processQueue = new PriorityQueue<>(new ProcessComparator());
+ }
+
+ @Override
+ public void start(String processId, long timestamp) {
+ startMap.put(processId, timestamp);
+ }
+
+ @Override
+ public void end(String processId, long timestamp) {
+ if (!startMap.containsKey(processId)) {
+ throw new Error("Cannot end process as it is not started");
+ }
+ Process process = new Process(processId, startMap.get(processId));
+ process.setEnd(timestamp);
+ processQueue.offer(process);
+ }
+
+ @Override
+ public String poll() {
+ if (processQueue.isEmpty()) {
+ throw new Error("No process remaining");
+ }
+ return processQueue.poll().toString();
+ }
+}