Java 如何在mateclipse中使用OQL进行嵌入式查询
我可以使用下面的查询获得所有线程对象Java 如何在mateclipse中使用OQL进行嵌入式查询,java,eclipse,oql,Java,Eclipse,Oql,我可以使用下面的查询获得所有线程对象 SELECT OBJECTS dominators(s) FROM java.lang.Thread s 然后,如果我想进一步分析返回的结果对象,我认为OQL应该如下所示: SELECT * from (SELECT OBJECTS dominators(s) FROM java.lang.Thread s) 但它变成了ClassCastException Problem reported: ClassCastException occured. Re
SELECT OBJECTS dominators(s) FROM java.lang.Thread s
然后,如果我想进一步分析返回的结果对象,我认为OQL应该如下所示:
SELECT * from (SELECT OBJECTS dominators(s) FROM java.lang.Thread s)
但它变成了ClassCastException
Problem reported:
ClassCastException occured. Remember: sub queries with the modifier INSTANCESOF or INCLUDING SUBCLASSES must return only class objects
java.lang.ClassCastException: org.eclipse.mat.parser.model.InstanceImpl cannot be cast to org.eclipse.mat.snapshot.model.IClass
at org.eclipse.mat.parser.internal.oql.OQLQueryImpl.doSubQuery(OQLQueryImpl.java:752)
at org.eclipse.mat.parser.internal.oql.OQLQueryImpl.internalExecute(OQLQueryImpl.java:642)
at org.eclipse.mat.parser.internal.oql.OQLQueryImpl.execute(OQLQueryImpl.java:627)
at org.eclipse.mat.inspections.OQLQuery.execute(OQLQuery.java:50)
at org.eclipse.mat.inspections.OQLQuery.execute(OQLQuery.java:1)
at org.eclipse.mat.query.registry.ArgumentSet.execute(ArgumentSet.java:129)
at org.eclipse.mat.ui.snapshot.panes.OQLPane$OQLJob.doRun(OQLPane.java:339)
at org.eclipse.mat.ui.editor.AbstractPaneJob.run(AbstractPaneJob.java:34)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
MAT Eclipse中的OQL是否支持嵌入式查询?如何获得所需的结果?使子查询工作起来有点棘手。请尝试以下操作:
SELECT * from OBJECTS (SELECT OBJECTS dominators(s) FROM java.lang.Thread s)
我从以下链接获得了解决方案:
正如消息中所说并有文档记录的那样,子查询必须返回类对象,请参见此处:也许您可以说明您试图通过这样的查询实现什么?是否要查看处于支配地位的线程?