WIP: Use Enum type instead of strings.

jacoco-maven-plugin/src/org/jacoco/maven/AbstractReportMojo.java

@@ -34,10 +34,6 @@
 public abstract class AbstractReportMojo extends AbstractMojo
 		implements MavenMultiPageReport {
 
-	static final String REPORT_XML = "XML";
-	static final String REPORT_HTML = "HTML";
-	static final String REPORT_CSV = "CSV";
-
 	/**
 	 * Encoding of the generated reports.
 	 */
@@ -49,7 +45,7 @@ public abstract class AbstractReportMojo extends AbstractMojo
 	 * CSV. Defaults to all formats if no values are given
 	 */
 	@Parameter
-	List<String> formats;
+	List<ReportFormat> formats;
 
 	/**
 	 * Name of the root node HTML report pages.
@@ -207,17 +203,17 @@ private void addFormatters(final ReportSupport support, final Locale locale)
 					footer, locale);
 		} else {
 			getOutputDirectory().mkdirs();
-			if (formats.contains(REPORT_CSV)) {
+			if (formats.contains(ReportFormat.CSV)) {
 				support.addCsvFormatter(
 						new File(getOutputDirectory(), "jacoco.csv"),
 						outputEncoding);
 			}
-			if (formats.contains(REPORT_XML)) {
+			if (formats.contains(ReportFormat.XML)) {
 				support.addXmlFormatter(
 						new File(getOutputDirectory(), "jacoco.xml"),
 						outputEncoding);
 			}
-			if (formats.contains(REPORT_HTML)) {
+			if (formats.contains(ReportFormat.HTML)) {
 				support.addHtmlFormatter(getOutputDirectory(), outputEncoding,
 						footer, locale);
 			}

jacoco-maven-plugin/src/org/jacoco/maven/ReportFormat.java

@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2021 Mountainminds GmbH & Co. KG and Contributors
+ * This program and the accompanying materials are made available under
+ * the terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Marc R. Hoffmann - initial API and implementation
+ *
+ *******************************************************************************/
+package org.jacoco.maven;
+
+/**
+ * Configurable output formats for the report goals.
+ */
+public enum ReportFormat {
+
+	/**
+	 * Multi-page html report.
+	 */
+	HTML,
+
+	/**
+	 * Single-file XML report.
+	 */
+	XML,
+
+	/**
+	 * Single-file CSV report.
+	 */
+	CSV
+
+}