public class MyChooseTag extends BodyTagSupport{
    private boolean executed;
    public void setExecuted(boolean ed){
        this.executed=ed;
    }
    public boolean getExecuted(){
        return executed;
    }
    public int doStartTag() throws JspException{
        executed=false;
        return EVAL_BODY_INCLUDE;
    }
    public int doEndTag() throws JspException{
        return EVAL_PAGE;
    }
}

public class MyIfTag extends BodyTagSupport{
    private boolean condition;
    public void setCondition(boolean condition){
        this.condition=condition;
    }
    public int doStartTag() throws JspException{
        MyChooseTag parent=(MyChooseTag)this.getParent();
        if(condition){
            parent.setExecuted(true);
            return EVAL_BODY_INCLUDE;
        }
        else{
            parent.setExecuted(false);
            return SKIP_BODY;
        }
    }
    public int doEndTag() throws JspException{
        return EVAL_PAGE;
    }
}

public class MyElseTag extends BodyTagSupport{
    public int doStartTag() throws JspException{
        MyChooseTag parent=(MyChooseTag)getParent();
            if(parent.getExecuted()){
                return SKIP_BODY;
            }
            else{
                return EVAL_BODY_INCLUDE;
            }
        }
}