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POHow to call an Oracle PL/SQL object super method
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copied!<p>I'd like to call an overridden PL/SQL method. Here's an example:</p> <pre><code>-- super class create or replace type test as object ( n number, member procedure proc(SELF in out nocopy test, s varchar2) ) alter type test not final / create or replace type body test is member procedure proc(SELF in out nocopy test, s varchar2) is begin dbms_output.put_line('test1: n='||nvl(self.n, 'null')||' s='||s); self.n := to_number(s); end; end; / -- derived class create or replace type test2 under test ( overriding member procedure proc(SELF in out nocopy test2, s varchar2) ) / </code></pre> <p>Now I want to invoke the inherited version of the <code>proc</code> method. When I try to do an explicit cast like <code>treat(self as test).proc(s);</code> it won't compile because of <strong>PLS-00363: expression 'SYS_TREAT' cannot be used as an assignment target</strong></p> <p>The type body compiles when I use a local variable:</p> <pre><code>create or replace type body test2 is overriding member procedure proc(SELF in out nocopy test2, s varchar2) is O test; begin O := treat(self as test); O.proc(s); end; end; / </code></pre> <p>But when I run my example like this</p> <pre><code>declare obj test2; begin obj := test2(0); obj.proc('1'); end; </code></pre> <p>...it throws <strong>ORA-21780: Maximum number of object durations exceeded.</strong></p> <p>Is there any way to call test::proc (without serializing/deserializing)?</p> <p>And... after proc has been called, how can any changed attributes (namely <code>n</code>) be reflected in <code>obj</code> ?</p> <hr> <p><strong>Update</strong> (Thanks, tbone):</p> <p>I changed the organization of my methods using template methods ('before' and 'after'). I add them whenever I need to extend a method.</p> <pre><code>create or replace type test as object ( n number, member procedure proc (SELF in out nocopy test, s varchar2), member procedure afterProc (SELF in out nocopy test, s varchar2) member procedure beforeProc(SELF in out nocopy test, s varchar2), ) not final / create or replace type body test is member procedure proc(SELF in out nocopy test, s varchar2) is begin beforeProc(s); dbms_output.put_line('test1: n='||nvl(n, 'null')||' s='||s); n := to_number(s); afterProc(s); end; member procedure afterProc (SELF in out nocopy test, s varchar2) is begin null; end; member procedure beforeProc(SELF in out nocopy test, s varchar2) is begin null; end; end; / </code></pre>

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