import java.io.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

public class CustomTag extends SimpleTagSupport {
    
    private String customAttribute;
    public void setCustomAttribute(String customAttribute) {
        this. customAttribute = customAttribute;
    }
    public String getCustomAttribute() {
        return customAttribute;
    }
    
    StringWriter stringWriter = new StringWriter();
    public void doTag() throws JspException, IOException {
        if (customAttribute != null) {
            // process tag attribute
            getJspContext().getOut().println(customAttribute);
        } else {
            // get the content from the tag body
            getJspBody().invoke(stringWriter);
            // process tag body’s content
            getJspContext().getOut().println(stringWriter.toString());
        }
    }

}