Addressing reviewers comments

src/main/java/edu/ie3/datamodel/io/csv/BufferedCsvWriter.java

@@ -12,6 +12,8 @@
 import java.util.Arrays;
 import java.util.Map;
 import java.util.Objects;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * This class extends the {@link BufferedWriter} and adds information about the file shape of the
@@ -83,9 +85,7 @@ public synchronized void write(Map<String, String> entityFieldData)
               + String.join(",", headLineElements)
               + "'.");
 
-    String[] entries =
-        Arrays.stream(headLineElements).map(entityFieldData::get).toArray(String[]::new);
-    writeOneLine(entries);
+    writeOneLine(Arrays.stream(headLineElements).map(entityFieldData::get));
   }
 
   /**
@@ -104,15 +104,18 @@ public final synchronized void writeFileHeader() throws IOException {
    * @throws IOException If writing is not possible
    */
   private void writeOneLine(String[] entries) throws IOException {
-    for (int i = 0; i < entries.length; i++) {
-      String attribute = entries[i];
-      super.append(attribute);
-      if (i + 1 < entries.length) {
-        super.append(csvSep);
-      } else {
-        super.append("\n");
-      }
-    }
+    writeOneLine(Arrays.stream(entries));
+  }
+
+  /**
+   * Write one line to the csv file
+   *
+   * @param entries Stream of entries to write
+   * @throws IOException If writing is not possible
+   */
+  private void writeOneLine(Stream<String> entries) throws IOException {
+    super.append(entries.collect(Collectors.joining(csvSep)));
+    super.append("\n");
     flush();
   }
 

src/test/groovy/edu/ie3/datamodel/io/csv/BufferedCsvWriterTest.groovy

@@ -83,12 +83,12 @@ class BufferedCsvWriterTest extends Specification {
 	def "The buffered csv writer writes out content in the order specified by the headline elements"() {
 		given:
 		def targetFile = FilenameUtils.concat(tmpDirectory.toString(), "order_test.csv")
-		def writer = new BufferedCsvWriter(targetFile, ["c", "b", "a"] as String[], ",", false)
+		def writer = new BufferedCsvWriter(targetFile, ["third_header", "second_header", "first_header"] as String[], ",", false)
 		writer.writeFileHeader()
 		def content = [
-				"c": "z",
-				"a": "x",
-				"b": "y"
+				"third_header": "third_value",
+				"first_header": "first_value",
+				"second_header": "second_value"
 		]
 
 		when:
@@ -105,7 +105,7 @@ class BufferedCsvWriterTest extends Specification {
 		}
 
 		then:
-		headline == "c,b,a"
-		writtenContent == "z,y,x"
+		headline == "third_header,second_header,first_header"
+		writtenContent == "third_value,second_value,first_value"
 	}
 }