复制不支持Ant-contrib嵌套循环中的嵌套“ if”元素

Question

I need to copy all dml.sql files to inside DB2_List.txt file if DML.sql file is present. But after executing this file i'm getting error like this: copy doesn't support the nested "if" element.

Please let me know if you have any better idea about the nested loop in Ant.

<available file="DB/DML.sql" property="db.check.present"/>
<copy file="DB/DDL.sql" tofile="DB2/DB2_List.txt" >
<if> 
 <equals arg1="${db.check.present}" arg2="true"/>
 <then> 
 <filterchain> 
    <concatfilter append="DB/DML.sql" /> 
    <tokenfilter delimoutput="${line.separator}" /> 
</filterchain> 
</then> 
</if> 
</copy>

Answer 1

It is possible to accomplish what you are after, you just have to approach it quite differently in Ant. Just note that you will need to utilize separate targets.

<target name="db.check">
  <available file="DB/DML.sql" property="db.check.present"/>
</target>
<target name="db.copy" depends="db.check" if="db.check.present">
  <copy file="DB/DDL.sql" tofile="DB2/DB2_List.txt" >
    <filterchain> 
      <concatfilter append="DB/DML.sql" /> 
      <tokenfilter delimoutput="${line.separator}" /> 
    </filterchain> 
  </copy>
</target>

Answer 2

Take a look at Ant 1.9.1 which supports special if/unless attributes on tags. This might be possible:

 <project name="mysterious.moe" basedir="."  default="package"
    xmlns:if="ant:if"
    xmlns:unless="ant:unless"/>

    <target name="db.copy">
        <available file="DB/DML.sql" property="db.check.present"/>
        <copy file="DB/DDL.sql" 
            tofile="DB2/DB2_List.txt">
            <filterchain if:true="db.ceck.present"> 
                <concatfilter append="DB/DML.sql" /> 
                <tokenfilter delimoutput="${line.separator}" /> 
            </filterchain> 
       </copy>
    <target>
...
</project>

Otherwise, you'll have to use two separate copies. You can't put <if> antcontrib inside tasks. Only around tasks:

<available file="DB/DML.sql" property="db.check.present"/>
<if> 
    <equals arg1="${db.check.present}" arg2="true"/>
    <then> 
        <copy file="DB/DDL.sql" tofile="DB2/DB2_List.txt" >
            <filterchain> 
                <concatfilter append="DB/DML.sql" /> 
                <tokenfilter delimoutput="${line.separator}" /> 
            </filterchain>
        </copy>
        </then>
        <else>
            <copy file="DB/DDL.sql" tofile="DB2/DB2_List.txt" >
        </else>
    </if> 
</copy>