Adding include directives using CDT

gistfile1.java

public static void includeHeaders(HashSet<String> headers, IASTTranslationUnit ast, IDocument document) {
  StringBuffer includeText = new StringBuffer();
  for(String headerName : headers) {
    if(!isHeaderAlreadyIncluded(headerName, ast)) {
      includeText.append("\n#include <" + headerName + ">");	
    }
  }

  if(includeText.length() > 0) {
    try {
      includeText.append("\n");
      int position = getPositionForIncludeStatements(ast);
      document.replace(position, 0, includeText.toString());
    } 
    catch (BadLocationException e) {
      Activator activator = Activator.getDefault();
      activator.getLog().log(new Status(Status.ERROR, Activator.PLUGIN_ID, Status.OK, "Unable to add include statement", e));
      throw new RuntimeException(e);
    }
  }
}
	
private static boolean isHeaderAlreadyIncluded(String headerName, IASTTranslationUnit ast) {
  IASTPreprocessorIncludeStatement[] includeStatements = ast.getTranslationUnit().getIncludeDirectives();
  for(IASTPreprocessorIncludeStatement includeStatement : includeStatements) {
    if(includeStatement.getName().getRawSignature().equals(headerName) && includeStatement.isSystemInclude()) {
      return true;
    }
  }	
  return false;
}

private static int getPositionForIncludeStatements(IASTTranslationUnit ast) {
  int position = 0;
		
  IASTPreprocessorIncludeStatement[] includeStatements = ast.getTranslationUnit().getIncludeDirectives();
  for(IASTPreprocessorIncludeStatement includeStatement : includeStatements) {
    if(includeStatement.isSystemInclude() && includeStatement.isPartOfTranslationUnitFile()) {
      IASTNodeLocation nodeLocation = includeStatement.getNodeLocations()[0];
      position = nodeLocation.getNodeOffset() + nodeLocation.getNodeLength();
    }
  }

  if(position == 0) {
    for(IASTPreprocessorStatement preprocessorStatement : ast.getAllPreprocessorStatements()) {
      if(preprocessorStatement instanceof IASTPreprocessorObjectStyleMacroDefinition) {
        IASTNodeLocation nodeLocation = preprocessorStatement.getNodeLocations()[0];
        position = nodeLocation.getNodeOffset() + nodeLocation.getNodeLength();
      }
    }
  }
  return position;
}