{"id":517,"date":"2012-01-01T20:40:19","date_gmt":"2012-01-01T19:40:19","guid":{"rendered":"http:\/\/doanduyhai.wordpress.com\/?p=517"},"modified":"2012-01-01T20:40:19","modified_gmt":"2012-01-01T19:40:19","slug":"advanced-aspectj-part-iv-declaring-aspects-precedence","status":"publish","type":"post","link":"https:\/\/www.doanduyhai.com\/blog\/?p=517","title":{"rendered":"Advanced AspectJ part IV : declaring aspects precedence"},"content":{"rendered":"

Today we discuss about aspects precedence e.g. the order in which several aspects are processed at the same join point.<\/p>\n

If you’re a heavy user of AspectJ you can sometimes end up with having more than one aspects for the same join point. In such case it could be interesting to know which aspect kicks in first and which one kicks in last. This order is called aspect precedence<\/em>.<\/p>\n

<\/p>\n

Without any specfic indication, the aspect ordering is totally unpredictable. It is not necessarily a problem if the aspects are totally unrelated.<\/p>\n

I Aspects ordering<\/h1>\n

To declare aspect precedence, you can use the special keyword<\/p>\n

declare precedence : <Type1Pattern>,<Type2Pattern>…<TypeNPattern>;<\/strong><\/p><\/blockquote>\n

In the above example, aspect1<\/strong>has precedence over aspect2<\/strong>, which in turn has precedence over aspect3<\/strong> etc. until aspectN<\/strong>.<\/p>\n

By “has precedence over<\/em>“, we mean “is executed before<\/em>“. Generally the aspect with highest precedence executes first. The execution order also depends on the type of advice<\/em>.<\/p>\n