Ref: remove duplicate handle code

src/main/java/com/sheepit/client/exception/SheepItExceptionBadResponseFromServer.java

@@ -19,7 +19,9 @@
 
 package com.sheepit.client.exception;
 
-public class SheepItExceptionBadResponseFromServer extends SheepItException {
+import java.util.concurrent.ThreadLocalRandom;
+
+public class SheepItExceptionBadResponseFromServer extends SheepItExceptionWithRequiredWait {
 	public SheepItExceptionBadResponseFromServer() {
 		super();
 	}
@@ -27,4 +29,12 @@ public class SheepItExceptionBadResponseFromServer extends SheepItException {
 	public SheepItExceptionBadResponseFromServer(String message_) {
 		super(message_);
 	}
+	
+	public String getHumanText() {
+		return "Bad answer from the server. Will try again at %tR";
+	}
+	
+	public int getWaitDuration() {
+		return 1000 * 60 * ThreadLocalRandom.current().nextInt(15, 30 + 1);
+	}
 }

src/main/java/com/sheepit/client/exception/SheepItExceptionServerInMaintenance.java

@@ -19,7 +19,9 @@
 
 package com.sheepit.client.exception;
 
-public class SheepItExceptionServerInMaintenance extends SheepItException {
+import java.util.concurrent.ThreadLocalRandom;
+
+public class SheepItExceptionServerInMaintenance extends SheepItExceptionWithRequiredWait {
 	public SheepItExceptionServerInMaintenance() {
 		super();
 	}
@@ -27,4 +29,12 @@ public class SheepItExceptionServerInMaintenance extends SheepItException {
 	public SheepItExceptionServerInMaintenance(String message_) {
 		super(message_);
 	}
+	
+	public String getHumanText() {
+		return "The server is under maintenance and cannot allocate a job. Will try again at %tR";
+	}
+	
+	public int getWaitDuration() {
+		return 1000 * 60 * ThreadLocalRandom.current().nextInt(20, 30 + 1);
+	}
 }

src/main/java/com/sheepit/client/exception/SheepItExceptionServerOverloaded.java

@@ -19,7 +19,9 @@
 
 package com.sheepit.client.exception;
 
-public class SheepItExceptionServerOverloaded extends SheepItException {
+import java.util.concurrent.ThreadLocalRandom;
+
+public class SheepItExceptionServerOverloaded extends SheepItExceptionWithRequiredWait {
 	public SheepItExceptionServerOverloaded() {
 		super();
 	}
@@ -27,4 +29,12 @@ public class SheepItExceptionServerOverloaded extends SheepItException {
 	public SheepItExceptionServerOverloaded(String message_) {
 		super(message_);
 	}
+	
+	public String getHumanText() {
+		return "The server is overloaded and cannot allocate a job. Will try again at %tR";
+	}
+	
+	public int getWaitDuration() {
+		return 1000 * 60 * ThreadLocalRandom.current().nextInt(10, 30 + 1);
+	}
 }

src/main/java/com/sheepit/client/exception/SheepItExceptionWithRequiredWait.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2023 Laurent CLOUET
+ * Author Laurent CLOUET <laurent.clouet@nopnop.net>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package com.sheepit.client.exception;
+
+/**
+ * When a request to the server generate this exception.
+ * The client must wait a bit before retrying.
+ */
+public class SheepItExceptionWithRequiredWait extends SheepItException {
+	public SheepItExceptionWithRequiredWait() {
+		super();
+	}
+	
+	public SheepItExceptionWithRequiredWait(String message_) {
+		super(message_);
+	}
+	
+	public String getHumanText() {
+		return "Please wait a bit";
+	}
+	
+	/** how much time, it needs to wait
+	 *
+	 * @return duration in ms
+	 */
+	public int getWaitDuration() {
+		return 0;
+	}
+}

src/main/java/com/sheepit/client/exception/SheepItServerDown.java

@@ -19,10 +19,12 @@
 
 package com.sheepit.client.exception;
 
+import java.util.concurrent.ThreadLocalRandom;
+
 /**
  * Server down (server side error) or unreachable (client side error)
  */
-public class SheepItServerDown extends SheepItException {
+public class SheepItServerDown extends SheepItExceptionWithRequiredWait {
 	public SheepItServerDown() {
 		super();
 	}
@@ -30,4 +32,12 @@ public class SheepItServerDown extends SheepItException {
 	public SheepItServerDown(String message_) {
 		super(message_);
 	}
+	
+	public String getHumanText() {
+		return "Cannot connect to the server. Please check your connectivity. Will try again at %tR";
+	}
+	
+	public int getWaitDuration() {
+		return 1000 * 60 * ThreadLocalRandom.current().nextInt(10, 30 + 1);
+	}
 }