fix #750 invalidate cache after updating suggest

src/main/java/org/codelibs/fess/helper/PopularWordHelper.java

@@ -89,6 +89,10 @@ public class PopularWordHelper {
         return Collections.emptyList();
     }
 
+    public void clearCache() {
+        cache.invalidateAll();
+    }
+
     protected String getCacheKey(final String seed, final String[] tags, final String[] roles, final String[] fields,
             final String[] excludes) {
         final StringBuilder buf = new StringBuilder(100);

src/main/java/org/codelibs/fess/job/SuggestJob.java

@@ -243,6 +243,7 @@ public class SuggestJob {
             if (exitValue != 0) {
                 throw new FessSystemException("Exit Code: " + exitValue + "\nOutput:\n" + it.getOutput());
             }
+            ComponentUtil.getPopularWordHelper().clearCache();
         } catch (final FessSystemException e) {
             throw e;
         } catch (final InterruptedException e) {