Scanning only packages specify in env. #168

src/main/java/com/thoughtworks/gauge/scan/ClasspathScanner.java

@@ -15,10 +15,6 @@
 
 package com.thoughtworks.gauge.scan;
 
-import java.io.File;
-import java.net.URL;
-import java.util.jar.JarFile;
-
 import com.thoughtworks.gauge.ClasspathHelper;
 import org.reflections.Configuration;
 import org.reflections.Reflections;
@@ -30,6 +26,12 @@
 import org.reflections.vfs.Vfs;
 import org.reflections.vfs.ZipDir;
 
+import java.io.File;
+import java.net.URL;
+import java.util.jar.JarFile;
+
+import static com.thoughtworks.gauge.GaugeConstant.PACKAGE_TO_SCAN;
+
 /**
  * Scans the current Classpath and passes to all the scanners passed.
  */
@@ -59,9 +61,23 @@ public Vfs.Dir createDir(URL url) throws Exception {
         Configuration config = new ConfigurationBuilder()
                 .setScanners(new MethodAnnotationsScanner(), new SubTypesScanner())
                 .addUrls(ClasspathHelper.getUrls())
-                .filterInputsBy(new FilterBuilder().include(".+\\.class"));
+                .filterInputsBy(this::shouldScan);
 
         return new Reflections(config);
     }
 
+    private boolean shouldScan(String s) {
+        final String packagesToScan = System.getenv(PACKAGE_TO_SCAN);
+        if (packagesToScan == null || packagesToScan.isEmpty()) {
+            return new FilterBuilder().include(".+\\.class").apply(s);
+        }
+        final String[] packages = packagesToScan.split(",");
+        for (String packageToScan : packages) {
+            String regex = String.format(".?\\.??%s.+\\.class", packageToScan);
+            if (new FilterBuilder().include(regex).apply(s)) {
+                return true;
+            }
+        }
+        return false;
+    }
 }