Solution for issue #816

Fixed the issue with traversing the tree and checking out if the getInstance method is used twice under the same class.

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/errorprone/SingleMethodSingletonRule.java

@@ -4,35 +4,58 @@
 
 package net.sourceforge.pmd.lang.java.rule.errorprone;
 
-import java.util.HashSet;
-import java.util.Set;
 
-import net.sourceforge.pmd.lang.java.ast.ASTCompilationUnit;
+import java.util.List;
+
+
+
+import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
 import net.sourceforge.pmd.lang.java.rule.AbstractJavaRule;
 
+/**
+ * Returns Checks if the singleton rule is used properly.
+ */
 public class SingleMethodSingletonRule extends AbstractJavaRule {
 
-    private Set<String> methodset = new HashSet<String>();
+    /**
+     * Checks for getInstance method usage in the same class.
+     * @param node of ASTCLass
+     * @param data of Object
+     * @return Object
+     *
+     */
 
-    @Override
-    public Object visit(ASTCompilationUnit node, Object data) {
-        methodset.clear();
-        return super.visit(node, data);
-    }
 
-    @Override
-    public Object visit(ASTMethodDeclaration node, Object data) {
-        if (node.getResultType().isVoid()) {
-            return super.visit(node, data);
-        }
+    public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
 
-        if ("getInstance".equals(node.getMethodName())) {
-            if (!methodset.add(node.getMethodName())) {
-                addViolation(data, node);
+        String a = node.getImage(); // Get the name of the Class it's part of
+        System.out.println(a);
+
+        List<ASTMethodDeclaration> methods = node.findDescendantsOfType(ASTMethodDeclaration.class); // Find the name of methods in it
+
+        System.out.println(methods);
+
+        int count = 0;
+        for (ASTMethodDeclaration method : methods) {
+
+            System.out.println(method.getName());
+            if (method.getName().equals("getInstance")) {
+                count++;
             }
+
         }
 
+        if (count > 1) {
+            System.out.println("error");
+            addViolation(data, node);
+        }
+
+        /*
+        Can now check if each class has only one getInstance methods than it's all sorted.
+        */
+
         return super.visit(node, data);
+
     }
 }