Ant:如何编写可选的嵌套元素 [英] Ant: how to write optional nested elements

问题描述

说我需要做这样的事情:

Say that I need to do something like:

<copy todir="${DEPLOYMENT_DIR}" overwrite="true">
    <fileset dir="dir1" />
    <fileset dir="dir2" />
    <fileset dir="dir3" />
    ...
    <if>
        <equals arg1="${SPECIAL_BUILD}" arg2="true"/>
        <then>
            <fileset dir="dir7" />
            <fileset dir="dir8" />
            ...
        </then>
    </if>
</copy>

(真正的任务不是复制，我只是用它来说明这一点.)

(The real task is not copy, I'm just using it to illustrate the point.)

Ant 会抱怨我的任务不支持嵌套的 ，这很公平.我一直在思考这些问题:

Ant will complain that my task doesn't support nested <if> which is fair enough. I've been thinking along these lines:

我可以像这样添加一个带有元素"属性的宏定义:

I could add a macrodef with an "element" attribute like this:

<macrodef name="myCopy">
    <element name="additional-path" />
    <sequential>
        <copy todir="${DEPLOYMENT_DIR}" overwrite="true">
            <fileset dir="dir1" />
            <fileset dir="dir2" />
            <fileset dir="dir3" />
            ...

            <additional-path/>
        </copy>
    </sequential>
</macrodef>

但这意味着调用者(目标)必须指定我想要避免的附加路径(如果许多目标调用此任务，他们将不得不重复 additional-path 元素).

But that would mean that the caller (target) must specify the additional path which I want to avoid (if many targets call this task, they would have to repeat the fileset definitions in the additional-path element).

如何在macrodef内对附加文件集进行编码，以便Ant 不会抱怨?

How to code the additional filesets inside the macrodef so that Ant doesn't complain?

推荐答案

实现这一目标的一种方法(不确定是否好)是创建两个宏定义 - 一个用于一般用途的公共"和一个用于通用的内部"真正的工作，旨在仅从公共"宏调用.像这样:

One way (not sure if a good one) to achieve that is to create two macrodefs - one "public" for general use and one "internal" that does the real work and is intended to be called only from the "public" macro. Like this:

<macrodef name="task-for-public-use">
    <sequential>
        <if>
            <equal arg1="${SPECIAL_BUILD}" arg2="true" />
            <then>
                <internal-task>
                    <additional-path>
                        ...
                    </additional-path>
                </internal-task>
            </then>
            <else>
                <internal-task ... />
            </else>
        </if>
    </sequential>
</macrodef>


<macrodef name="internal-task">
    <element name="additional-path" />
    <sequential>
        <copy ...>
            ...
            <additional-path/>
        </copy>
    </sequential>
</macrodef>

不过我不太喜欢它，希望有更好的方法.

I don't like it much though and hope there's a better way.

这篇关于Ant:如何编写可选的嵌套元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！