问Ant构建中不完整参数的异常处理

EN

<project name="option-test" default="default">

  <!--
    This is the main target. It depends on target check-parameter which fails,
    if parameter restoreValue is not set.
  -->
  <target name="default" depends="check-parameter">
    <echo message="Start build ..." />
    <echo message="restoreValue = ${restoreValue}" />
  </target>

  <!--
    This helper target sets property parameterok to true, if restoreValue is set.
    And to false, otherwise.
  -->
  <target name="check-is-set">
    <condition property="parameterok">
      <isset property="restoreValue"/>
    </condition>
  </target>

  <!--
    This target depends on target check-is-set, which calculates the parameterok property.
    The unless attribute evaluates the parameterok property, so that the target body
    is only excuted, if paramterok=false.
    So the build fails only if parameter restoreValue is not set.
  -->
  <target name="check-parameter" unless="${parameterok}" depends="check-is-set">
    <fail message="Parameter restoreValue not set!" />
  </target>

<fail>
    <condition>
        <or>
            <not>
                <matches
                    string="${sun.java.command}"
                    pattern=" -DrestoreValue[ =]"
                />
            </not>
            <matches
                string="${sun.java.command}"
                pattern=" -D.+ -D"
            />
        </or>
    </condition>
</fail>