Merge pull request #454 from lionsoul2014/fr_java_config_builder_assert

assert the builder data source args to avoid errors like reported on…

binding/java/pom.xml

@@ -4,7 +4,7 @@
 
     <groupId>org.lionsoul</groupId>
     <artifactId>ip2region</artifactId>
-    <version>3.3.4</version>
+    <version>3.3.5</version>
     <packaging>jar</packaging>
 
     <name>ip2region</name>

binding/java/src/main/java/org/lionsoul/ip2region/service/ConfigBuilder.java

@@ -49,16 +49,19 @@ public class ConfigBuilder {
     }
 
     public ConfigBuilder setXdbPath(String xdbPath) {
+        assert xdbPath != null && xdbPath.length() > 0;
         this.xdbPath = xdbPath;
         return this;
     }
 
     public ConfigBuilder setXdbFile(File xdbFile) {
+        assert xdbFile != null;
         this.xdbFile = xdbFile;
         return this;
     }
 
     public ConfigBuilder setXdbInputStream(InputStream xdbInputStream) {
+        assert xdbInputStream != null;
         this.xdbInputStream = xdbInputStream;
         return this;
     }