独自のテンプレートエンジンを作成する(4)

public class ActionTag extends TagSupport implements com.skin.ayada.tagext.ParameterTag{
    private String className;
    private String method;
    private String page;
    private Parameters parameters = new Parameters();

    @Override
    public int doStartTag(){
        super.doStartTag();
        this.parameters.clear();
        return TagSupport.EVAL_PAGE;
    }

    @Override
    public int doEndTag(){
        Map<String, Object> context = null;

        if(this.className != null)
        {
            //            ,                  
            context = ActionDispatcher.dispatch(pageContext, this.parameters, this.className, this.method);
        }

        if(this.getPage() != null)
        {
            //           
            //         pageContext,                        PageContext
            //            
            TemplateManager.execute(this.getPage(), context, pageContext.getOut());
        }

        return TagSupport.EVAL_PAGE;
    }

    @Override
    public void setParameter(String name, Object value){
        parameters.setParameter(name, value);
    }

    // getter & setter
    ...
}

public class ParameterTag extends BodyTagSupport{
    private String name;
    private String value;

    @Override
    public int doEndTag()
    {
        Tag parent = this.getParent();

        if(parent instanceof com.skin.ayada.tagext.ParameterTag)
        {
            String value = this.getValue();

            if(value == null)
            {
                BodyContent body = this.getBodyContent();
                value = (body != null ? body.getString() : null);
            }

            com.skin.ayada.tagext.ParameterTag tag = (com.skin.ayada.tagext.ParameterTag)(parent);
            tag.setParameter(this.getName(), value);
            return TagSupport.EVAL_PAGE;
        }
        else
        {
            throw new RuntimeException("Illegal use of parameter-style tag without servlet as its direct parent");
        }
    }

    // getter & setter
    ...
}