handle errors in makeBucket, removeBucket and DeleteObject examples. (#…

…386)

* examples/MakeBucket: create bucket if it doesn't exist.

* examples/RemoveBucket: remove bucket if it exists.

* example/RemoveObject: handle MinioException when removing object.

examples/MakeBucket.java

@@ -32,8 +32,14 @@ public static void main(String[] args)
     // Set s3 endpoint, region is calculated automatically
     MinioClient s3Client = new MinioClient("https://s3.amazonaws.com", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY");
 
-    // Create bucket 'my-bucketname'.
-    s3Client.makeBucket("my-bucketname");
-    System.out.println("my-bucketname is created successfully");
+    // Create bucket if it doesn't exist.
+    boolean found = s3Client.bucketExists("my-bucketname");
+    if (found) {
+      System.out.println("my-bucketname already exists");
+    } else {
+      // Create bucket 'my-bucketname'.
+      s3Client.makeBucket("my-bucketname");
+      System.out.println("my-bucketname is created successfully");
+    }
   }
 }

examples/RemoveBucket.java

@@ -32,9 +32,14 @@ public static void main(String[] args)
     // Set s3 endpoint, region is calculated automatically
     MinioClient s3Client = new MinioClient("https://s3.amazonaws.com", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY");
 
-    // Remove bucket 'my-bucketname'.
+    // Remove bucket 'my-bucketname' if it exists.
     // This operation will only work if your bucket is empty.
-    s3Client.removeBucket("my-bucketname");
-    System.out.println("my-bucketname is removed successfully");
+    boolean found = s3Client.bucketExists("my-bucketname");
+    if (found) {
+      s3Client.removeBucket("my-bucketname");
+      System.out.println("my-bucketname is removed successfully");
+    } else {
+      System.out.println("my-bucketname does not exist");
+    }
   }
 }

examples/RemoveObject.java

@@ -33,7 +33,12 @@ public static void main(String[] args)
     MinioClient s3Client = new MinioClient("https://s3.amazonaws.com", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY");
 
     // Remove object 'my-objectname' in 'my-bucketname'.
-    s3Client.removeObject("my-bucketname", "my-objectname");
-    System.out.println("successfully removed my-bucketname/my-objectname");
+    try {
+      s3Client.removeObject("my-bucketname", "my-objectname");
+      System.out.println("successfully removed my-bucketname/my-objectname");
+    } catch (MinioException e) {
+      System.out.println("Failed to remove object");
+      System.out.println("Error: " + e);
+    }
   }
 }