Fulltext search: searching for NULL or an empty string threw an exception.

h2/src/main/org/h2/fulltext/FullText.java

@@ -469,7 +469,7 @@ public class FullText {
         while (rs.next()) {
             String schema = rs.getString("TRIGGER_SCHEMA");
             String name = rs.getString("TRIGGER_NAME");
-            if (name.startsWith(TRIGGER_PREFIX)) {
+            if (name.startsWith(prefix)) {
                 name = StringUtils.quoteIdentifier(schema) + "." + StringUtils.quoteIdentifier(name);
                 stat2.execute("DROP TRIGGER " + name);
             }
@@ -506,6 +506,9 @@ public class FullText {
             // this is just to query the result set columns
             return result;
         }
+        if (text == null || text.trim().length() == 0) {
+            return result;
+        }
         FullTextSettings setting = FullTextSettings.getInstance(conn);
         HashSet<String> words = New.hashSet();
         addWords(setting, words, text);

h2/src/main/org/h2/fulltext/FullTextLucene.java

@@ -326,6 +326,9 @@ public class FullTextLucene extends FullText {
             // this is just to query the result set columns
             return result;
         }
+        if (text == null || text.trim().length() == 0) {
+            return result;
+        }
         String path = getIndexPath(conn);
         try {
             IndexModifier indexer = getIndexModifier(conn);

h2/src/test/org/h2/test/db/TestFullText.java

@@ -92,6 +92,8 @@ public class TestFullText extends TestBase {
         stat = conn.createStatement();
         ResultSet rs = stat.executeQuery("SELECT * FROM " + prefix + "_SEARCH('Hello', 0, 0)");
         assertTrue(rs.next());
+        stat.executeQuery("SELECT * FROM " + prefix + "_SEARCH(NULL, 0, 0)");
+        stat.execute("INSERT INTO TEST VALUES(2, NULL)");
         conn.close();
     }