Improve getter folding (fixes #90)

Small refactor to improve readability
Thanks to mibac138 for pointing in to right direction

Author: jfcabral

src/com/intellij/advancedExpressionFolding/AdvancedExpressionFoldingBuilder.java

@@ -1761,18 +1761,15 @@ && startsWith(((PsiMethodCallExpression) argument).getMethodExpression().getRefe
             }
 
         }
-        if (settings.getState().isGetSetExpressionsCollapse()) {
-            if (identifier.isPresent() && ((startsWith(identifier.get().getText(), "get") && identifier.get().getText().length() > 3)
-                    || (identifier.get().getText().startsWith("is") && identifier.get().getText().length() > 2))
-                    && element.getArgumentList().getExpressions().length == 0) {
+        if (settings.getState().isGetSetExpressionsCollapse() && identifier.isPresent()) {
+            if (isGetter(identifier.get(), element)) {
                 return new Getter(element, element.getTextRange(), TextRange.create(identifier.get().getTextRange().getStartOffset(),
                         element.getTextRange().getEndOffset()),
                         qualifier != null
                                 ? getAnyExpression(qualifier, document)
                                 : null,
                         guessPropertyName(identifier.get().getText()));
-            } else if (identifier.isPresent()
-                    && identifier.get().getText().startsWith("set")
+            } else if (identifier.get().getText().startsWith("set")
                     && identifier.get().getText().length() > 3
                     && Character.isUpperCase(identifier.get().getText().charAt(3))
                     && element.getArgumentList().getExpressions().length == 1
@@ -1790,6 +1787,17 @@ && startsWith(((PsiMethodCallExpression) argument).getMethodExpression().getRefe
         return null;
     }
 
+    private static boolean isGetter(@NotNull PsiElement element, @NotNull PsiMethodCallExpression expression) {
+        return expression.getArgumentList().getExpressions().length == 0
+                && (isGetterAux(element.getText(), "get") || isGetterAux(element.getText(), "is"));
+    }
+
+    private static boolean isGetterAux(@Nullable String name, @NotNull String prefix) {
+        return startsWith(name, prefix)
+                && name.length() > prefix.length()
+                && Character.isUpperCase(name.charAt(prefix.length()));
+    }
+
     static int findDot(@NotNull Document document, int position, int i) {
         int offset = 0;
         while (Math.abs(offset) < 100 && position > 0 && position < document.getText().length() && !document.getText(TextRange.create(position, position + 1)).equals(".")) {