groovy - 如何制作 "StringWriterMarkupBuilder"

Question

如何创建一个 MarkupBuilder 类型，但具有使用 StringWriter 初始化的默认构造函数，并重写 toString() 来调用 StringWriter 上的 toString()？

想法如下，但当然不允许在 super 构造函数调用之前初始化实例变量:

class StringWriterMarkupBuilder extends MarkupBuilder {
    final def sw = new StringWriter()
    StringWriterMarkupBuilder() {
        super(sw)
    }

    @Override String toString() {
        sw.toString()
    }
}

Answer 1

抱歉，我终于通过深入研究 MarkupBuilder 的 Groovy 源代码找到了解决方案!:

class StringWriterMarkupBuilder extends MarkupBuilder {
    StringWriterMarkupBuilder() {
        //MarkupBuilder.this(new IndentPrinter(new PrintWriter(writer)))
        super(new StringWriter()) 
    }

    @Override String toString() {
        //IndentPrinter.PrintWriter.StringWriter
        return super.getPrinter().out.out.toString()
    }
}