#1510 Improvments done in Circuit Breaker

circuit-breaker/src/main/java/com/iluwatar/circuitbreaker/DelayedRemoteService.java

@@ -0,0 +1,68 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.circuitbreaker;
+
+/**
+ * This simulates the remote service It responds only after a certain timeout period (default set to
+ * 20 seconds).
+ */
+public class DelayedRemoteService implements RemoteService {
+
+  private final long serverStartTime;
+  private final int delay;
+
+  /**
+   * Constructor to create an instance of DelayedService, which is down for first few seconds.
+   *
+   * @param delay the delay after which service would behave properly, in seconds
+   */
+  public DelayedRemoteService(long serverStartTime, int delay) {
+    this.serverStartTime = serverStartTime;
+    this.delay = delay;
+  }
+
+  public DelayedRemoteService() {
+    this.serverStartTime = System.nanoTime();
+    this.delay = 20;
+  }
+
+  /**
+   * Responds based on delay, current time and server start time if the service is down / working.
+   *
+   * @return The state of the service
+   */
+  @Override
+  public String call() throws RemoteServiceException {
+    var currentTime = System.nanoTime();
+    //Since currentTime and serverStartTime are both in nanoseconds, we convert it to
+    //seconds by diving by 10e9 and ensure floating point division by multiplying it
+    //with 1.0 first. We then check if it is greater or less than specified delay and then
+    //send the reply
+    if ((currentTime - serverStartTime) * 1.0 / (1000 * 1000 * 1000) < delay) {
+      //Can use Thread.sleep() here to block and simulate a hung server
+      throw new RemoteServiceException("Delayed service is down");
+    }
+    return "Delayed service is working";
+  }
+}