I want to create my own Boolean operation on an element to pass in as a FilterRule. The ElementPasses member description states:
Derived classes override this method to implement the test that determines whether the given element passes this rule or not.
I have tried to create my own derived class but I can't figure out how to implement it. I would think an interface would be available but I can't find anything. Annoyingly, I remember seeing an example of this but I can't seem to find anything.
This fails with: Static class 'ParameterDefinitionExists' cannot derive from type 'FilterRule'. Static classes must derive from object.
static public class ParameterDefinitionExists : FilterRule
{
public static bool ElementPasses(Element element)
{
return true;
}
}
And this fails with:'FilterRule' does not contain a constructor that takes 0 arguments
static public class ParameterDefinitionExists : FilterRule
{
new public bool ElementPasses(Element element)
{
return true;
}
}
What constructor arguments does it take?
There may be another way to go about it but I can't anything for FilterRules. I'm trying to define and refine a trigger in an updater but maybe I should query the element after it is passed in to the command. I imagine catching it with a filter rule is more efficient.
You have to use one of the Revit API classes derived from FilterRule:
Inheritance Hierarchy
System Object
Autodesk.Revit.DB FilterRule
Autodesk.Revit.DB FilterCategoryRule
Autodesk.Revit.DB FilterInverseRule
Autodesk.Revit.DB FilterValueRule
Autodesk.Revit.DB SharedParameterApplicableRule
Cf. http://www.revitapidocs.com/2017/a8f202ca-3c88-ecc4-fa93-549b26a412d7.htm
The Building Coder provides several examples creating and using parameter filters:
http://thebuildingcoder.typepad.com/blog/2010/08/elementparameterfilter-with-a-shared-parameter.html
Here is the entire topic group on filtering.
Related
I'm trying to examine (at a bytecode level, ASM) classes implementing some specific interfaces (in this case, java.sql.Connection) and find that in some cases, the library has another interface extending something from my set of interfaces... and then their classes implement THAT interface. (In this case, a new extended interface com.mysql.jdbc.Connection extend java.sql.Connection and then their implementations, e.g, ConnectionImpl implement com.mysql.jdbc.Connection.) I therefore miss identifying ConnectionImpl as a target class.
So.. the result is that I need to identify com.mysql.jdbc.Connection as an 'interesting' interface when loading the class. But I can't see how to identify the class AS an interface versus just a normal class. Is there something in the ClassReader than can give me that sort of information?
As per the title, if you want to check if a class is an interface:
ClassNode node = // However you wish to load the class
if ((node.access & Opcodes.ACC_INTERFACE) != 0){
// is interface
} else {
// is not an interface
}
In your post you state you wish to find children/implementations of java.sql.Connection.
The issue you're having is this:
java.sql.Connection -> com.mysql.jdbc.Connection -> ConnectionImpl
ConnectionImpl does not directly implement java.sql.Connection so it's not detected as a child/implementation. For an issue like this what you would have to do is travel the class hierarchy. If I were in your situation I would load a map of ClassNodes <String, ClassNode> where the string is the ClassNode's name. Then I would use a recursive method to check if a given class is the intended type. So if you send a ClassNode in it would call itself with the node's parent and then the interfaces. Eventually if the initially given node is the correct type eventually the java.sql.Connection interface will be passed through and found. Also if you wanted to skip redundencies you could store the results of each ClassNode in a map so that you wouldn't have to check the entire hierarchy over and over again.
Edit: Sorta like this
public static boolean isMatch(ClassNode cn, Map<String,ClassNode> nodes, String target){
if (cn.name.equals(target)) return true;
else{
if (nodes.containsKey(cn.superName) && isMatch(nodes.get(cn.superName),nodes,target)) return true;
for (String interf : cn.interfaces){
if (nodes.containsKey(interf) && isMatch(nodes.get(interf),nodes,target)) return true;
}
}
return false;
}
As you already mentioned, you need to check every interface type for its interfaces in order to determine such a subtype-relation. This is however not difficult to do if you have access to all resources.
When you are using ASM, you simply need to take the interface names of your original class and find the class file to each such interface. You can then parse each class file for its interfaces and so on. This way, you can determine the entire graph and decide on the subtype relationship.
If you do not want to do this manually, you can use Byte Buddy which offers you methods similar to the reflection API for unloaded types:
ClassFileLocator cfl = ... // can be file system, class loader, etc.
TypePool.Default.of(cfl).describe("your.initial.type")
.resolve()
.isAssignableTo(someInterface);
You can also use the TypePool to read the target interface, if it is not available.
Using org.objectweb.asm.ClassReader ,we can identify loaded class is really a class or interface. Sample code snippet is below
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException{
ClassReader classReader = null;
try{
classReader=new ClassReader(classfileBuffer);
if(isInterface(classReader)){
return classfileBuffer;
}
}
catch(Throwable exp){
return classfileBuffer;
}
// Remaining logic here
}
public boolean isInterface(ClassReader cr) {
return ((cr.getAccess() & 0x200) != 0);
}
There is a method that check it for you Class#isInterface()
if (yourClass.isInterface()) {
//do something
}
http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Class.html#isInterface%28%29
You can use isInterface() method of java.lang.Class to check whether a class is an interface or not.
Consider the following code:
// ======== Abstract class ========
public abstract class Creatures {
public abstract void loseEnergy();
public void execute()
{
loseEnergy();
}
}
// ======== Animals ========
public class Animals : Creatures
{
public override void loseEnergy(){}
}
public class Birds : Animals
{
public override void loseEnergy(){}
}
// ======== Human ========
public class Human : Creatures
{
public override void loseEnergy(){}
}
public class Male : Human
{
public override void loseEnergy(){}
}
public class Female : Human
{
public override void loseEnergy(){}
}
[ This code was based on the code by Jayson suggested here: "Base class methods calling derived class methods ?" ]
In the given code example, I would like to have the runtime executing EACH derived class object's certain method, in this case, which is 'loseEnergy()', however, I could not find the solution.
How do I approach this problem?
What can be useful to know or to try.. in order to solve this issue?
Your help is very much appreciated!
Thank you!
Kind regards,
Segara
P.S. Some search I have done so far:
"How to call overriden methods in all derived classes"
"Collection of derived classes that have generic base class"
"How to call derived function using base class object"
"Call method of the derived class through reflection possible or no"
EDIT:
I decided to stick to the idea I had before which is to have some list that would contain the objects of the classes that have 'loseEnergy()' method. Having such list I will be able to call every object's method 'loseEnergy()', which is what I wanted.
Question can be closed.
Thank you.
I didn't really understand your problem but anyway i can try to give you some means to use abstract classes :
If you use a abstract method, you SHOULD override it in a subclasses (like a method declared in an interface)
If you want that all inherited class use a same method, you can implement it in the abstract class ; all subclasses will use the method you implements if you don't override it, you've have to not declare it in the subclasses (extends < ABS_CLASS > is good enough)
If you want use a method of the abstract class which is override in the sub class you can use the keyword super .
I hope it will help you.
if you mean that you want the calls: female.loseEnergy() -> human.loseEnergy() -> creature.loseEnergy(), call the base method in the first line of the overriden one
public class Female : Human
{
public override void loseEnergy()
{
base.loseEnergy();
// do stuff
}
}
In the Greenfoot environment that you mention in the post above, the act() method is called only on actors which have been added into the "world". Internally, this adds them into a list. The simulation process iterates through the list and calls act() on each object in turn. Objects that are not "in the world" are not known to the system and so do not have their act method called. There is no magic here going on here.
If you wanted similar behaviour but without manually adding objects into a list, you could possibly have the base class constructor add new objects into a global list. I don't know C# so I don't know precisely how to do this, but I cannot imagine it would be difficult.
I'm trying to dynamicly crate an annotation that will dynamicaly add an #XmlElement annotation to every field in a class using metaprogramming and AST. I'm having problems creating the annotations and applying them to the fields properly.
The code i have is formatted here: http://pastebin.com/60DTX5Ya
import javax.xml.bind.annotation.XmlElement
#GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
class WebserviceAnnotationModifier implements ASTTransformation {
#Override
void visit(ASTNode[] astNodes, SourceUnit sourceUnit) {
if (!astNodes) return
if (!astNodes[0] || !astNodes[1]) return
if (!(astNodes[0] instanceof AnnotationNode)) return
if (!(astNodes[1] instanceof ClassNode)) return
ClassNode node = (ClassNode)astNodes[1]
List fields = node.getFields()
fields.each {FieldNode field ->
field.addAnnotation(ClassHelper.make(new XmlElement.DEFAULT()));
}
}
}
#Retention(RetentionPolicy.SOURCE)
#Target([ElementType.TYPE])
#GroovyASTTransformationClass(classes =[WebserviceAnnotationModifier])
public #interface WebresourceAnnotation{}
#WebresourceAnnotation
class TestPerson{
String name;
String lastName;
int Age
}
Am i approaching this all wrong? The reason i do this is i have a domain that is still in the making and i'd like to just go in and apply the annotation to all fields. Couldn't find any examples of annotations added during compilation. Is this not possible?
Writing codes using Groovy AST Transformation alone does not work with the Grails reloading mechanism. Here's a proper way to implement AST transformation for a Grails app.
Your transformer class must extends AbstractGrailsArtefactTransformer.
Your transformer class must be annotated by #AstTransformer.
You class must be put under org.codehaus.groovy.grails.compiler or its sub-package. In my case I use org.codehaus.groovy.grails.compiler.zk and it's working fine.
Implement shouldInject() to match only classes you want, in this case domain classes.
Override performInjection() and write your codes there.
Pack your transformer and releated classes into a .jar file, or Grails compiler does not load it.
I have a dictionary that contains classes. However, I have a lot of classes to add to the dictionary and I would like to eliminate the long list of adds, because it's starting to look messy. I was thinking of having all the data in a file and loading it to add to the dictionary, but then I realized that every time I wanted to create and add a new class, I would have to modify the file. I would prefer to have to include something in my newly created class that would automatically add it to the dictionary. I'm not even sure this is possible, so I would appreciate any help.
Try to use reflection to dynamically locate all the required classes. Create an instance of Assembly where your classes are defined and try to filter them out. An example below shows how to locate all the classes whose name ends with Task.
var assembly = Assembly.GetExecutingAssembly();
var taskTypes = assembly.GetTypes()
.Where(t => t.Name.EndsWith("Task") && t.IsClass);
Dictionary<string, object> instances =
new Dictionary<string, object>(taskTypes.Count());
foreach (Type classType in taskTypes)
{
object instance = Activator.CreateInstance(classType);
instances.Add(classType.Name, instance);
Console.WriteLine("Registered key {0} with object of type {1})",
classType.Name,
instance);
}
I've used Activator.CreateInstance method to create instances of your classes, but this might not be possible in your case depending on whether they have parameterless contructors etc.
Another option might be to use one of the available IoC containers like autofac but I need more details on your problem before I can give a proper advice on this.
Make the dictionary a static field of some class, or make the "add class to dictionary" a static method.
Then, you can use a static constructor to add each class to the dictionary:
class ClassDict {
...
public static void AddClass(Type t) {
...
}
}
class Foo {
static Foo() {
ClassDict.AddClass(typeof(Foo));
}
}
There are a lot of workarounds for the missing support of enumerations in the Entity Framework 4.0. From all of them I like this one at most:
http://blogs.msdn.com/b/alexj/archive/2009/06/05/tip-23-how-to-fake-enums-in-ef-4.aspx?PageIndex=2#comments
This workaround allows you to use enums in your LINQ queries which is what i exactly need. However, I have a problem with this workaround. I get for every complex type I'm using a new partial autogenerated class.Therefore the code does not compile any more because I already have a wrapper class with this name in the same namespace which converts betwen the backed integer in the database and the enum in my POCO classes. If I make my wrapper a partial class, the code still does not compile as it now contains two properties with the same name "Value". The only possibility is to remove the Value property by hand everytime I generate the POCO classes because the DB model changed (which during the development phase happens very often).
Do you know how to prevent a partial class to be generated out of complex property everytime the EF model changes?
Can you recommend me some other workarounds supporting enumerations in LINQ queries?
That workaround is based on the fact that you are writing your POCO classes yourselves = no autogeneration. If you want to use it with autogeneration you must heavily modify T4 template itself.
Other workaround is wrapping enum conversion to custom extension methods.
public static IQueryable<MyEntity> FilterByMyEnum(this IQueryable<MyEntity> query, MyEnum enumValue)
{
int val = (int)enumValue;
return query.Where(e => e.MyEnumValue == val);
}
You will then call just:
var data = context.MyEntitites.FilterByMyEnum(MyEnum.SomeValue).ToList();
I am using an approach based on the one described in your link without any modifications of the T4 templates. The contents of my partial wrapper classes are as follows:
public partial class PriorityWrapper
{
public Priority EnumValue
{
get
{
return (Priority)Value;
}
set
{
Value = (int)value;
}
}
public static implicit operator PriorityWrapper(Priority value)
{
return new PriorityWrapper { EnumValue = value };
}
public static implicit operator Priority(PriorityWrapper value)
{
if (value == null)
return Priority.High;
else
return value.EnumValue;
}
}
I've only changed that instead of a back store variable with enum value I am using the autogenerated int typed Value property. Consequently Value can be an auto-implemented property and EnumValue property needs to do the conversion in getter and setter methods.