What we generate is effectively something along the lines of
public class JavassistMethod1 implements JavassistMethod
{
public Object invoke(Object target, Object[] args) throws Throwable
{
if (target == null)
throw new IllegalArgumentException("Null target");
if (target instanceof SomeClass == false)
throw new IllegalArgumentException("Wrong target");
if (args == null || args.length != 10)
throw new IllegalArgumentException("Wrong number of parameters");
if (args[0] == null)
throw new IllegalArgumentException("Parameter 1 cannot be null for SomeClass.someMethod(long, String)");
if (args[0] != null && args[0] instanceof Long == false)
throw new IllegalArgumentException("Parameter 1 is not an instance of Long for SomeClass.someMethod(long, String)");
if (args[1] != null && args[1] instanceof String == false)
throw new IllegalArgumentException("Parameter 2 is not an instance of String for SomeClass.someMethod(long, String)");
return ((SomeClass)target).someMethod(((Long)args[0]).longValue(), (String)args[1]);
}
}
Disabling the parameter checking so we end up with this instead reduces the time spent in C from about 4.8s to 3.8s
public class JavassistMethod1 implements JavassistMethod
{
public Object invoke(Object target, Object[] args) throws Throwable
{
return ((SomeClass)target).someMethod(((Long)args[0]).longValue(), (String)args[1]);
}
}
Profiling this, for each JavassistMethod implementation the time taken is roughly
50% generating the bytecode for the method
30% Converting the bytecode to a byte array and creating the class
13% creating the constructor
6% setting the interfaces
Maybe a better approach would be
1) to do the parameter checking in Javassist[Constructor/Method/Field]Info itself
2) to generate less classes? Something like:
public class SomeBeanAccessor implements JavassistBeanAccessor
{
public Object newInstance(int index, Object[] args) throws Throwable
{
if (index == 0)
return new SomeClass((String)args[0]);
else if (index == 1)
return new SomeClass((String)args[1]);
return null;
}
public Object invoke(long hash, Object target, Object[] args) throws Throwable
{
if (hash == 121267912)
return ((SomeClass)target).someMethod(((Long)args[0]).longValue(), (String)args[1]);
if (hash == 128172981)
return ((SomeClass)target).otherMethod(((Long)args[0]).longValue(), (String)args[1], (String)args[2]);
}
public Object get(String name, Object target) throws Throwable
{
if (name.equals("intField")
return Integer.valueOf(((SomeClass)target).intField);
if (name.equals("stringField")
return ((SomeClass)target).stringField;
}
public void set(String name, Object target, Object value) throws Throwable
{
if (name.equals("intField")
((SomeClass)target).intField = ((Integer)value).intValue();
return;
if (name.equals("stringField")
((SomeClass)target).stringField = (String)value;
}
}
First call by Javassist[Constructor/Method/Field]Info to access the member would result in this being created for ALL members, and cached in JavassistTypeInfo.