recyclebin5385 created OGNL-238:
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Summary: OGNLRuntime doesn't handle parameterized method arguments
correctly for a grandchild class of a generic class
Key: OGNL-238
URL: https://issues.apache.org/jira/browse/OGNL-238
Project: Commons OGNL
Issue Type: Bug
Components: Core Runtime
Affects Versions: 3.0
Environment: Windows 7 64bit, Java Runtime Environment 7
Reporter: recyclebin5385
Suppose there are classes as described below.
Class Foo<T> is a generic class with a type parameter T.
It has a property named "x" whose type is T; Foo has methods "T getX()" and
"void setX(T x)".
Class Bar is a direct derived class of Foo<Integer>.
Class Baz is a direct derived class of Bar and class Qux is a direct derived
class of Baz.
In short, there is an inheritance tree like this: Foo<T> -> Bar -> Baz -> Qux.
Static method ognl.Ognl.setValue(String expression, Object root, Object value)
has an ability to resolve a type parameter of an argument of a method.
But it does not work well for a derived class of a generic class.
If you execute Ognl.setValue("tmp.x", root, "123") where "tmp" is an instance
of class Bar, "123" is converted to an Integer and tmp's property X is set to
an Integer.
It is a natural behavior because Bar extends Foo<Integer> and tmp's property x
should be an Integer.
But, if tmp is an instance of class Baz or Qux, which are both derived classes
of Bar, the conversion is never performed and tmp's property X is set to String
"123".
It seems that type parameter handling works only when the class is DIRECTLY
derived from a generic class.
Here is a test code.
You will need to add ognl-3.0.6.jar and javassist-3.11.0.GA.jar to the
classpath in order to execute the code. They are bundled in Struts2.3.15.1.
------
import java.text.MessageFormat;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import ognl.Ognl;
class Foo<T> {
private T m_x;
public T getX() {
return m_x;
}
public void setX(T x) {
m_x = x;
}
}
class Bar extends Foo<Integer> {
}
class Baz extends Bar {
}
class Qux extends Baz {
}
public class OgnlBugTest {
public static void main(String[] args) {
try {
Map<String, Foo<?>> root = new LinkedHashMap<String, Foo<?>>();
root.put("foo", new Foo<Short>());
root.put("bar", new Bar());
root.put("baz", new Baz());
root.put("qux", new Qux());
Ognl.setValue("foo.x", root, "1");
Ognl.setValue("bar.x", root, "2");
Ognl.setValue("baz.x", root, "3");
Ognl.setValue("qux.x", root, "4");
for (Entry<String, Foo<?>> entry : root.entrySet()) {
System.out.println(MessageFormat.format("{0} = {1} ({2})",
entry.getKey(), entry.getValue().getX(), entry.getValue().getX().getClass()));
}
} catch (Exception exception) {
exception.printStackTrace();
}
}
}
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