allow multiple source files to be used in parsing

langserver/java/source-types.js

@@ -555,6 +555,8 @@ class SourceImport {
 }
 
 class SourceUnit {
+    /** @type {string} */
+    uri = '';
     /** @type {Token[]} */
     tokens = [];
     /** @type {SourcePackage} */
@@ -614,6 +616,13 @@ class SourceUnit {
             method,
         };
     }
+
+    /**
+     * Return the name of the package this unit belongs to
+     */
+    get packageName() {
+        return (this.package_ && this.package_.name) || '';
+    }
 }
 
 class SourceArrayType extends ArrayType {