[MDEP-939] Lock down classifier in dependency:sources goal

This closes #409

src/it/projects/sources/test.properties

@@ -5,9 +5,9 @@
 # to you under the Apache License, Version 2.0 (the
 # "License"); you may not use this file except in compliance
 # with the License.  You may obtain a copy of the License at
-# 
+#
 #   http://www.apache.org/licenses/LICENSE-2.0
-# 
+#
 # Unless required by applicable law or agreed to in writing,
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
@@ -16,3 +16,5 @@
 # under the License.
 
 outputFile = target/resolved.txt
+# This is intentional to prove that no classifier is passed (read-only value)
+classifier = foo

src/main/java/org/apache/maven/plugins/dependency/resolvers/ResolveDependencySourcesMojo.java

@@ -18,9 +18,9 @@
  */
 package org.apache.maven.plugins.dependency.resolvers;
 
-import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.plugins.annotations.ResolutionScope;
 
 /**
@@ -36,19 +36,10 @@
         threadSafe = true)
 public class ResolveDependencySourcesMojo extends ResolveDependenciesMojo {
 
-    private static final String SOURCE_CLASSIFIER = "sources";
+    private static final String SOURCES_CLASSIFIER = "sources";
 
-    /**
-     * Main entry into mojo. Gets the list of dependencies and iterates through resolving the source jars.
-     *
-     * @throws MojoExecutionException with a message if an error occurs.
-     */
-    @Override
-    protected void doExecute() throws MojoExecutionException {
-        if (this.classifier == null || this.classifier.isEmpty()) {
-            this.classifier = SOURCE_CLASSIFIER;
-        }
-
-        super.doExecute();
+    @Parameter(name = "classifier", defaultValue = SOURCES_CLASSIFIER, readonly = true)
+    public void setClassifier(String classifier) {
+        this.classifier = classifier;
     }
 }