startCache throws an IllegalParameterExcpetion if the method gets called with illegal parameters

src/main/java/hhn/labsw/bugageocaching/controller/Controller.java

@@ -2,6 +2,7 @@ package hhn.labsw.bugageocaching.controller;
 
 import com.google.gson.Gson;
 import hhn.labsw.bugageocaching.entities.*;
+import hhn.labsw.bugageocaching.exceptions.IllegalParameterException;
 import hhn.labsw.bugageocaching.repositories.*;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.*;
@@ -41,9 +42,9 @@ public class Controller {
   @RequestMapping("/startCache")
   public @ResponseBody
   String startCache(@RequestParam(value = "userID", defaultValue = "-1") String userID,
-                    @RequestParam String cacheID) {
+                    @RequestParam String cacheID) throws IllegalParameterException {
 
-    if (!userID.equals("-1")) { // ein angemeldeter User startet den Cache
+    if (!userID.equals("-1")) { // ein angemeldeter user startet den cache(es werden zwei parameter übergeben)
 
       Bearbeitet bearbeitet = new Bearbeitet();
 
@@ -52,7 +53,7 @@ public class Controller {
         User user = userOptional.get();
         bearbeitet.setUser(user);
       } else {
-        return "There is no user with the ID " + userID;
+        throw new IllegalParameterException("There is no user with the ID " + userID);
       }
 
       Optional<Cache> cacheOptional = cacheRepository.findById(Integer.valueOf(cacheID));
@@ -60,7 +61,7 @@ public class Controller {
         Cache cache = cacheOptional.get();
         bearbeitet.setCache(cache);
       } else {
-        return "There is no cache with the ID " + cacheID;
+        throw new IllegalParameterException( "There is no cache with the ID " + cacheID);
       }
 
       Optional<CacheAccesDefinition> cacheAccesDefinitionOptional =
@@ -69,20 +70,20 @@ public class Controller {
         CacheAccesDefinition cacheAccesDefinition = cacheAccesDefinitionOptional.get();
         bearbeitet.setCacheAccesDefinition(cacheAccesDefinition);
       } else {
-        return "There is no cacheAccesDefinition with the ID " + 1;
+        throw new IllegalParameterException("There is no cacheAccesDefinition with the ID " + 1);
       }
 
       bearbeitetRepository.save(bearbeitet);
 
       return new Gson().toJson(bearbeitet);
 
-    } else { // kein angemeldeter User startet den Cache
+    } else { // kein angemeldeter User startet den cache(es wird nur der cache als parameter übergeben)
       Optional<Cache> cacheOptional = cacheRepository.findById(Integer.valueOf(cacheID));
       if (cacheOptional.isPresent()) {
         Cache cache = cacheOptional.get();
         return new Gson().toJson(cache);
       } else {
-        return "There is no cache with the ID " + cacheID;
+        throw new IllegalParameterException( "There is no cache with the ID " + cacheID);
       }
     }
   }

src/main/java/hhn/labsw/bugageocaching/exceptions/IllegalParameterException.java

@@ -0,0 +1,65 @@
+package hhn.labsw.bugageocaching.exceptions;
+
+
+/**
+ * Thrown to indicate that a method has been passed an illegal or inappropriate argument.
+ * This matches the IllegalArgumentException, but is no RuntimeException. This forces the
+ * developer to catch it.
+ * <p>
+ */
+public class IllegalParameterException extends Exception {
+  /**
+   * Constructs a new exception with {@code null} as its detail message.
+   * The cause is not initialized, and may subsequently be initialized by a
+   * call to {@link #initCause}.
+   */
+  public IllegalParameterException() {
+  }
+
+  /**
+   * Constructs a new exception with the specified detail message.  The
+   * cause is not initialized, and may subsequently be initialized by
+   * a call to {@link #initCause}.
+   *
+   * @param message the detail message. The detail message is saved for
+   *                later retrieval by the {@link #getMessage()} method.
+   */
+  public IllegalParameterException(final String message) {
+    super(message);
+  }
+
+  /**
+   * Constructs a new exception with the specified detail message and
+   * cause.  <p>Note that the detail message associated with
+   * {@code cause} is <i>not</i> automatically incorporated in
+   * this exception's detail message.
+   *
+   * @param message the detail message (which is saved for later retrieval
+   *                by the {@link #getMessage()} method).
+   * @param cause   the cause (which is saved for later retrieval by the
+   *                {@link #getCause()} method).  (A <tt>null</tt> value is
+   *                permitted, and indicates that the cause is nonexistent or
+   *                unknown.)
+   * @since 1.4
+   */
+  public IllegalParameterException(final String message, final Throwable cause) {
+    super(message, cause);
+  }
+
+  /**
+   * Constructs a new exception with the specified cause and a detail
+   * message of <tt>(cause==null ? null : cause.toString())</tt> (which
+   * typically contains the class and detail message of <tt>cause</tt>).
+   * This constructor is useful for exceptions that are little more than
+   * wrappers for other throwables.
+   *
+   * @param cause the cause (which is saved for later retrieval by the
+   *              {@link #getCause()} method).  (A <tt>null</tt> value is
+   *              permitted, and indicates that the cause is nonexistent or
+   *              unknown.)
+   * @since 1.4
+   */
+  public IllegalParameterException(final Throwable cause) {
+    super(cause);
+  }
+}