Thread: Java files compilation with java code

Look at the JavaCompiler interface.

Here are some samples I got from somewhere:

import java.io.*;
import java.util.*;
import javax.tools.*;
import javax.tools.JavaCompiler.*;
import java.net.URI;
import java.lang.reflect.Method;
 
 
public class JavaCompilationTest3 {
 
	public static void main(String[] args) throws Exception {
      JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
		DiagnosticCollector<JavaFileObject> diagnosticsCollector =
			                                            new DiagnosticCollector<JavaFileObject>();
		StandardJavaFileManager fileManager  =
                             compiler.getStandardFileManager(diagnosticsCollector, null, null);
      JavaFileObject javaObjectFromString = getJavaFileContentsAsString();
      Iterable<? extends JavaFileObject> fileObjects = Arrays.asList(javaObjectFromString);
 
      CompilationTask task = compiler.getTask(null, fileManager, diagnosticsCollector, null, null, fileObjects);
		Boolean result = task.call();
 
 
      List<Diagnostic<? extends JavaFileObject>> diagnostics = diagnosticsCollector.getDiagnostics();
 
		for(Diagnostic<? extends JavaFileObject> d : diagnostics){
			// Print all the information here.
         System.out.println(d.getMessage(null)); 
		}
 
		if(result == true){
			System.out.println("Compilation has succeeded");
         // Now execute it
         Class tc = Class.forName("TestClass");
//         System.out.println("tc=" + tc);
         Method[] methods = tc.getDeclaredMethods();
         try {
           Method testMethod = tc.getMethod("testMethod", new Class[]{}); 
         //warning: [unchecked] unchecked call to getMethod(java.lang.String,java.lang.Class<?>...) 
         //as a member of the raw type java.lang.Class
 
           testMethod.invoke(null, new Object[]{});  // Call TestClass's testMethod()
 
         }catch(Exception x) {
           x.printStackTrace();
         }
		}else{
			System.out.println("Compilation fails.");
		}
	}
 
   //------------------------------------------------------------------
   static class JavaObjectFromString extends SimpleJavaFileObject{
       private String contents = null;
 
       public JavaObjectFromString(String className, String contents) throws Exception{
       		super(new URI(className), Kind.SOURCE);
            this.contents = contents;
       }
       public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
       		return contents;
       }
   } // end class
 
	private static SimpleJavaFileObject getJavaFileContentsAsString(){
		StringBuilder javaFileContents = new StringBuilder("" +
				"class TestClass{" +
				"	public static void testMethod(){" +
	         "		System.out.println(" + "\" this is a  test message.\"" +           ");" +
				"}" +
				"}");
		JavaObjectFromString javaFileObject = null;
		try{
         javaFileObject = new JavaObjectFromString("TestClass", javaFileContents.toString());
		}catch(Exception exception){
			exception.printStackTrace();
		}
		return javaFileObject;
	} // end class
}

// Auto parsing code
import java.io.*;
import java.util.*;
import javax.tools.*;
import javax.tools.JavaCompiler.*;
import java.net.URI;
import java.lang.reflect.Method;
 
 
// Define classes needed here
interface TestQuestionSaver {
  public void AddQuestion(Question q);
}  
 
 
class Array {
  String[] array;
  Array(String a1, String a2, String a3) {
   array = new String[] {a1, a2, a3};
  }
} // end class Array
 
class Question {
  String url, ques, what;
  Array choices;
  int type;
  boolean answer;
  String sAnswer;
 
  public Question(String url, String ques, int type, Array choices, boolean answer, String what){
    this.url = url;
    this.ques = ques;
    this.type = type;
    this.choices = choices;
    this.what = what;
    this.answer = answer;
  }
  public Question(String url, String ques, int type, Array choices, String sAnswer, String what){
    this.url = url;
    this.ques = ques;
    this.type = type;
    this.choices = choices;
    this.sAnswer = sAnswer;
    this.what = what;
  }
} // end class Question
 
 
//---------------------------------------------------------------------
public class TestQuestionParser implements TestQuestionSaver {
 
// Define the program to compile and execute as a String
   String pgmPart1a = "class ";
   String pgmPart1b =  " {"
      + " public static void addQuestions(TestQuestionSaver test) {\n"
      + "   final int QUESTION_TYPE_CHOICE = 1;\n"
      + "   final int QUESTION_TYPE_TF = 2;\n";
 
         // The code to "parse" goes between these lines of ********s
         //*************************************************************************************************************
   String code = 
          " test.AddQuestion( new Question (\"com.scorm.golfsamples.interactions.etiquette_1\","
          + "                            \"When Another player is attempting a shot, it is best to stand:\"," 
          + "                            QUESTION_TYPE_CHOICE,"
          + "                            new Array(\"On top of his ball\", \"Directly in his line of fire\", \"Out of the player's line of sight\"),"
          + "                            \"Out of the player's line of sight\","
          + "                            \"obj_etiquette\")"
          + "      );\n"
          + " test.AddQuestion( new Question (\"com.scorm.golfsamples.interactions.etiquette_2\","
          + "                            \"Generally sand trap rakes should be left outside of the hazard.\","
          + "                            QUESTION_TYPE_TF,"
          + "                            null,"
          + "                            true,"
          + "                            \"obj_etiquette\")"
          + "      );\n"
          + " test.AddQuestion( new Question (\"com.scorm.golfsamples.interactions.etiquette_3\","
          + "                            \"The player with the best score on the previous hole tees off:\"," 
          + "                            QUESTION_TYPE_CHOICE,"
          + "                            new Array(\"First\", \"Last\", \"With a putter\"),"
          + "                            \"First\","
          + "                            \"obj_etiquette\")"
          + "      );\n";   
 
       //************************************************************************************************ 
       String pgmPart2 = "}\n }";    // wrapup method and class
 
 
 
   //----------------------------------------------
   // Start here
   public static void main(String[] args) {
     new TestQuestionParser();
   }
 
   //----------------------------------------------------------------------------------
   public TestQuestionParser()  {
     // Here create the .java file and compile it and then call its addQuestion method
     String className = "TestQuestions2";      // The name of class we're generating
     String source = pgmPart1a + className + pgmPart1b+ code + pgmPart2;
 
     // Put together the parts necessary to compile the above code
      JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
		DiagnosticCollector<JavaFileObject> diagnosticsCollector =
			                                            new DiagnosticCollector<JavaFileObject>();
		StandardJavaFileManager fileManager  =
                             compiler.getStandardFileManager(diagnosticsCollector, null, null);
      JavaFileObject javaObjectFromString = getJavaFileContentsAsString(className, source);
      Iterable<? extends JavaFileObject> fileObjects = Arrays.asList(javaObjectFromString);
 
      // Compile it
      CompilationTask task = compiler.getTask(null, fileManager, diagnosticsCollector, null, null, fileObjects);
		Boolean result = task.call();
 
      // Show error messages
      List<Diagnostic<? extends JavaFileObject>> diagnostics = diagnosticsCollector.getDiagnostics();
 
		for(Diagnostic<? extends JavaFileObject> d : diagnostics){
			// Print all the information here.
         System.out.println(d.getMessage(null)); 
		}
 
      // Test results
		if(result == true){
			System.out.println("Compilation has succeeded");
         // Now execute it
         try {
           Class tc = Class.forName(className);
//         System.out.println("tc=" + tc);
           Method[] methods = tc.getDeclaredMethods();
           Method testMethod = tc.getMethod("addQuestions", new Class[]{TestQuestionSaver.class}); 
         //warning: [unchecked] unchecked call to getMethod(java.lang.String,java.lang.Class<?>...) 
         //as a member of the raw type java.lang.Class
 
           testMethod.invoke(null, new Object[]{this});  // Call addQuestions
 
         }catch(Exception x) {
           x.printStackTrace();
         }
		}else{
			System.out.println("Compilation fails.");
		}
 
   } // end constructor
 
   //------------------------------------------------------------------
   class JavaObjectFromString extends SimpleJavaFileObject{
       private String contents = null;
 
       public JavaObjectFromString(String className, String contents) throws Exception{
       		super(new URI(className), Kind.SOURCE);
            this.contents = contents;
       }
       public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
       		return contents;
       }
   } // end class
 
	private SimpleJavaFileObject getJavaFileContentsAsString(String className, String source){
		StringBuilder javaFileContents = new StringBuilder(source);
		JavaObjectFromString javaFileObject = null;
		try{
         javaFileObject = new JavaObjectFromString(className, javaFileContents.toString());
		}catch(Exception exception){
			exception.printStackTrace();
		}
		return javaFileObject;
	} // end getJavaFileContensAsString
 
   //------------------------------------------------------------------------------
   // The call-back interface method will get the data from the calls made to it
  public void AddQuestion(Question q) {
     System.out.println("url=" +q. url + ", ques=" + q.ques + "\n   answer=" + q.sAnswer);
  }
}     
/*   
Running: D:\Java\jdk1.6.0_25\jre\bin\java.exe  -Xmx512M -classpath D:\JavaDevelopment;. TestQuestionParser
 
Compilation has succeeded
url=com.scorm.golfsamples.interactions.etiquette_1, ques=When Another player is attempting a shot, it is best to stand:
   answer=Out of the player's line of sight
url=com.scorm.golfsamples.interactions.etiquette_2, ques=Generally sand trap rakes should be left outside of the hazard.
   answer=null
url=com.scorm.golfsamples.interactions.etiquette_3, ques=The player with the best score on the previous hole tees off:
   answer=First
 
0 error(s)
*/