Configuring Log4j in Junit TestCases

As a developer we often have to test our business codes through different kinds of test cases. For my java objects I prefer Apache's JUnit Test cases. At many points in our code we have to log messages on output consoles or files. There are many logging API's are available but Apache's Log4j is widely used these days. One of the most important feature of Lo4j is that we can even log our messages to different files based on the java objects i.e based on there fully qualified package names.

Well, but the topic I am going to discuss here is how to configure our test cases to show our log messages on our standard output? Following are the steps we should keep in mind for successful configuration.

1. If our test-cases has to be executed through Ant target then first let us create a target in our build.xml
2. Log4j.properties file at specified location contains all the configurations required for log4j loggers and apenders.
3. In our test cases we have to create and initialize our logger before we can use it to log our information. Here I have created a test case named SampleTest in package com.tests.project. The most essential point to remember that in constructor or inside init() method we have to call configure() method of BasicConfigurator object else it won't read the properties of Log4j.properties file.
4. We can add any method named test***() which will get execute when we call ant target from command line as folows:
   D:\Workspace\Blog>ant _unittest -Dtest.class=com.tests.project.SampleTest

Following all the mentioned steps give your logger informations into standard console. Note: Don't forget to call BasicConfigurator.configure() mentioned in step 3.

Htm Truncator Lucene Analyzer

On my recent SpellChecker project I had a module, in which I required spelling dictionary (i.e. Lucene Index) based on lucene NGramAnalyzers, reading from 1000's of .htm files we had in our repository. For this I have taken an advantage of lucene's extension capabilities by creating my own Analyzer to truncate the html tags since it was not required to store them in spelling dictionary. An Analyzer is an encapsulation of the analysis process.

Creating lucene Analyzer is very simple and easy task as we just have to extend Analyzer class which also have have only one method to override i.e.

public TokenStream tokenStream( String fieldName, Reader reader){}

TokenStream comes in two flavour i.e. Tokenizer and TokenFilter . Distinction is that Tokenizer deals with individual characters whereas TokenFilter deals with words. One important aspect is that we can create chain of these tokenstreams so that output of one object can be used as input for another object. In Tokenizer, the input should be in the form of Reader class. So what I have done that created a analyzer similar to StandardAnalyzer and supplied a new Reader object, which will truncate any words between '<' '>' characters from .htm files.

Following is the code of my HtmTagTruncatorAnalyzer class

public class MyStandardAnalyzer extends Analyzer{
private Set stopWords;
public MyStandardAnalyzer(){
  stopWords = StopFilter.makeStopSet(StopAnalyzer.ENGLISH_STOP_WORDS);
}

public MyStandardAnalyzer(String[] stopWords){
     this.stopWords = StopFilter.makeStopSet(StopAnalyzer.ENGLISH_STOP_WORDS);
     this.stopWords.addAll(StopFilter.makeStopSet(stopWords));
}

public TokenStream tokenStream(String fieldName,Reader reader) {
   return new StopFilter(new LowerCaseFilter(new StandardFilter
         (new StandardTokenizer(getNewReader(reader)))),stopWords);
}

private Reader getNewReader(Reader reader){
StringBuffer tempBuffer = new StringBuffer();
try{
  boolean result = true;
  int length = 0;
  loop1:while(true){
  int character = reader.read();
  char c = (char)character;
  if(character == -1) {
     break;
  }
  if(c == '<'){
       result = false;
  }
  if(result == true){
      if(c == '.' ){
           tempBuffer.append(' ');
           continue loop1;
      }    
      if(c == '0' ||c == '1' ||c == '2' ||c == '3'||c == '4' ||
         c == '5'||c == '6'||c == '7'||c == '8'||c == '9'||c == '&'||
         c == ','||c == '-'||c == '_'||c == '@'){
         tempBuffer.append(' ');
         continue loop1;
      }
      tempBuffer.append(c);
 }else if(result == false && c == '>'){
     result = true;
     tempBuffer.append(' ');
 }
}
}catch(Exception e){
e.printStackTrace();
}

String text = tempBuffer.toString();
return new StringReader(text);
}

}

Hibernate's Solution for org.hibernate.hql.ast.QuerySyntaxException.

It take a more then 2 hours to me to solve this exception. I am sharing it with you guys so that new comers won't face it.

Suppose I have persistent object named 'User' mapped to Database table 'USER_DETAILS' in my User.hbm.xml file. When I tried to get object through HQL query ie
User user = session.createQuery("from User_Details where User_Id=1 ).uniqueResult();

I got " org.hibernate.hql.ast.QuerySyntaxExcepti

on: User_Details is not mapped [from User_Details where USER_ID=1".

Solution : I found that in HQL we have to supply persistent Object class name instead of DB table name in queries to retrieve object. i.e.
User user = session.createQuery("from User where User_Id=1 ).uniqueResult();

Regards

Mohit Agrawal

Introduction

Hi,

This is my first acquaintance with writing blogs. Still much not aware what to write but writing to see something in my blogs. One of the reason for writing blog is to get used to working with for Blog Server technology. At same time i am also going through reading a book on Blog sever technology i.e RSS and Atom in Action.