I have four java classes, each containing a test. They must remain like this; I can't put the four tests in one file.
Each file has a small setup portion at the top:
private SQSRequestCreator sqsRequestCreator;
private AssociateErgoTriggerStateDAO associateErgoTriggerStateDao;
#Inject
ClassName(SQSRequestCreator sqsRequestCreator, AssociateErgoTriggerStateDAO associateErgoTriggerStateDAO) {
this.sqsRequestCreator = sqsRequestCreator;
this.associateErgoTriggerStateDao = associateErgoTriggerStateDAO;
}
Each test uses the variables created above. This works! But, I would like to refactor this as to not have this code duplicated across 4 classes. I would like to have just one occurrence, and have the classes refer to it. I am not 100% sure this is possible, since the method in question is a constructor.
I tried making an abstract class like so:
public abstract class TestSetup {
public SQSRequestCreator sqsRequestCreator;
public AssociateErgoTriggerStateDAO associateErgoTriggerStateDao;
#Inject
TestSetup(SQSRequestCreator sqsRequestCreator, AssociateErgoTriggerStateDAO associateErgoTriggerStateDAO) {
this.sqsRequestCreator = sqsRequestCreator;
this.associateErgoTriggerStateDao = associateErgoTriggerStateDAO;
}
But this only works because the instance variables are public. They should be private. If anyone could suggest a way to refactor this code, I would be very grateful.
Thanks!
Related
I have an application which produces a GraphViz dot file for a subgraph of my Neo4j database. It works like a charm, but there is somewhat of an issue.
Right now, the title of each node is the node id. Then the properties are listed, with their respective types. This is more information than I need and I would like to change the way the GraphViz writer is configured.
I noticed several classes/interfaces such as GraphStyle, StyleParameter, StyleConfiguration but I've tried several things and keep running into the issue that I cannot access certain classes/interfaces outside of their respective package. Maybe I'm doing it wrong, maybe it's designed so users cannot reconfigure the GraphViz writer, I don't know but I'd like to know.
How do I reconfigure the GraphViz writer so the dot file contains only that information which I want it to contain, namely a property of my choosing as the title, and nothing else as far as the nodes are concerned. Also, this is not always the same property, so for some nodes I'd like property A to be the title, and for nodes that don't have property A, I'd like property B to be the title.
Any help would be greatly appreciated.
You could try using the styles provided by this class: https://github.com/neo4j/neo4j/blob/master/community/graphviz/src/main/java/org/neo4j/visualization/graphviz/AsciiDocSimpleStyle.java
It might be useful to look into this class as well: https://github.com/neo4j/neo4j/blob/master/community/graphviz/src/main/java/org/neo4j/visualization/asciidoc/AsciidocHelper.java
I managed to get it to work. First of all, you need to create two new classes:
class NodeStyleImpl implements NodeStyle
class RelationshipStyleImpl implements RelationshipStyle
Here you can define how nodes and relations should be written in the dot notation. An example implementation looks like this :
public class NodeStyleImpl implements NodeStyle {
public void emitNodeStart(Appendable apndbl, Node node) throws IOException {
apndbl.append(" N" + node.getId() + " [\n label = \"");
}
public void emitEnd(Appendable apndbl) throws IOException {
apndbl.append("\"\n]\n");
}
public void emitProperty(Appendable apndbl, String propkey, Object propvalue) throws IOException {
if(propkey.equals("propkeyone") || propkey.equals("propkeytwo"){
apndbl.append(propvalue.toString());
}
}
}
In an analog fashion, you can write the RelationshipStyleImpl. If you're looking for more advanced configuration, you can also write a StyleConfiguration implementation. You can look at the default implementations in the Neo4j code for an example.
Then there's the issue with the GraphStyle class. The GraphStyle class has a constructor which is protected, thus only accessible from within the package. I made a pull request to change it to public but for the moment, here's a little "hack" which provides a workaround.
package org.neo4j.visualization.graphviz
public class GraphStyleImpl extends GraphStyle {
private GraphStyleImpl (NodeStyleImpl nstyle, RelationshipStyleImpl rstyle) {
super(nstyle, rstyle);
}
}
Note the package declaration. Because the GraphStyle constructor is protected, the super(nstyle, rstyle) method is only accessible from within the same package. By extending the class with a new public constructor, you can now do the following:
GraphStyle graphstyle = new GraphStyleImpl(new NodeStyleImpl(), new RelationshipStyleImpl());
GraphvizWriter writer = new GraphvizWriter(graphstyle);
If my pull request gets accepted, the use of the GraphStyleImpl class will no longer be necessary.
I need a little help understanding how classes work in Actionscript 3. I understand you start with "package" and why and then go to import any necessary libraries, as well as then naming the class and stating if it's public/private and extends anything.
After that is what I don't understand. It seems you write "(public) function class name()
I don't understand why you do this and what goes in the curly brackets.
I've probably missed a bit of earlier reading because I've done a little reading but I can't seem to get it.
Could someone try explain it to me? Thanks.
ActionScript 3 Classes
The package statement.
Okay, so firstly like you mentioned, a class must be wrapped by a package1. This gives us the first block, where you need to define the class.
package
{
// Your class here.
}
The package statement reflects the location of the class relative to the .fla2. For example, if you have a folder "classes" within the same directory as the project .fla, then classes within that folder will need a package statement that reflects that:
package classes
{
// Your class here.
}
Defining the class.
Within a package statement, you may insert one class. Do not confuse this with the package itself, which can contain many classes - each class just needs to have its own file with the same package statement.
A class definition is made up of up to 5 parts:
The namespace. A class can be internal or public. An internal class can only be seen by classes within the same package, whereas public classes can be seen from anywhere in the project.
The class name.
A base class (optional). If a base class is defined, then your new class will act as an extension to that class, inheriting all of the qualities of the base class.
An interface to implement (optional). Interfaces are an advanced topic thus I suggest you forget about these for now until your AS3 and OOP have evolved.
If you wanted to create a class called "Person" within the package classes, then we would end up with:
package classes
{
public class Person
{
// Class qualities here.
}
}
Properties.
Classes can contain properties. Properties are defined using the var keyword. They may belong to one of a number of namespaces (including your own) and are used to hold values that belong to your class. Properties are most commonly found clustered together at the top of your class.
Our Person class may enjoy the properties height and weight:
package classes
{
public class Person
{
// Properties.
public var height:Number = 1.70;
public var weight:Number = 67.5;
}
}
These properties can be accessed via any instance of Person that you create. Each instance will have its own set of these properties.
Class constructors (I believe this is what you're asking about).
Constructors are used to hold logic that should be run as soon as an instance of your class is created. The class constructor has the same name as the class itself. It must be public and it does not return anything. Constructors can accept arguments, which are typically used to pass in references to dependencies for that class or required values.
package classes
{
public class Person
{
// Properties.
public var height:Number = 1.70;
public var weight:Number = 67.5;
// Constructor.
public function Person(height:Number, weight:Number)
{
this.height = height;
this.weight = weight;
}
}
}
Methods.
Methods are used to hold logic that can be run when calling that method. Methods often return values and can accept arguments. Methods can belong to any namespace that you would expect properties to be able to belong to.
We may want to be able to easily determine the BMI of each instance of Person that we create, so we should create a method for that:
package classes
{
public class Person
{
// Properties.
public var height:Number = 170;
public var weight:Number = 65.5;
// Constructor.
public function Person(height:Number, weight:Number)
{
this.height = height;
this.weight = weight;
}
// Determine my BMI and return the result.
public function getBMI():Number
{
return weight / (height * height);
}
}
}
Instances.
Now that we've defined our new class, we can create instances of this class using the new keyword. This can be done from anywhere that can access the Person class, which in this case is anywhere in the project because we've made the class public.
Though the class is public, accessing it from anywhere outside of the package it belongs in will require the use of an import statement. This statement will need to be used within any class that belongs to a different package. The import statement follows the same name used for the package and includes the name of the class you want to include on the end:
import classes.Person;
Once you've imported Person, you can create instances of it and assign them to a variable with different height and weight values:
var marty:Person = new Person(71, 1.76);
var bruce:Person = new Person(96.4, 1.72);
We can then obtain the BMI for each person using their getBMI() method:
trace(marty.getBMI()); // 22.9
trace(bruce.getBMI()); // 32.6
1 You can place classes outside of a package which can be referred to in the same .as file.
2 You can add more source paths, and packages can be relative to that.
The function that have the same name as class is a constructor. In curly brackets is basically part of code that will execute instantly when object will be created. Try to search info about constructors, they exist I think in every object oriented programming language (I may be wrong), so you have a lot of resources.
You can also read about this concept on Wikipedia.
The function that is named the same as the class is the constructor. It's optional, so you can leave it out if you don't need it. A default constructor will be added, which essentially does nothing.
The constructor lets you write code that executes immediately after an instance of the class is created (ie when another bit of code runs new ClassName(). You would typically use it to initialise some variables that are used by the class. Defining a constructor also lets you handle constructor arguments, which other code can pass when they use the new operator.
I would like to modify an Accordion class to suit my needs.
Instead of simply extending Accordion, I would like to copy and paste the whole class as a start, with the new class name "MyAccordion", into the src folder; to gain the maximum freedom(I assume).
However, several problems encountered. For the "include "../core/Version.as";" error, I had solved by replacing it with a explicit Version static const string. But for the problems lead by the inheritance, e.g. AccordionHeader, etc, I found that there would be too many files to be edited when going down the stream. I suspect I mis-understand the whole logic of editing the class.
Would anyone give me some help? May be some reference for me to read, or even just some keywords for me to search. Thanks in advance.
Well - for all the reasons your discovering, you actually don't have flexibility when leveraging "boilerplate" code like this. Use Extend and Override to properly modify existing classes:
package com.yourSite.src
{
public class Foo
{
public function Foo
{
}
public function foo():void
{
trace("foo");
}
}
}
package com.yourSite.src
{
public class Bar extends Foo
{
public function Bar
{
}
override public function foo():void
{
trace("bar");
}
}
}
So, write a class that Extends Accordion, and override anything that you want to work differently. Any other functionality you may need can be added as required. OOP 101 :D
Check out the link above for a more cohesive discussion.
Cheers!
Hi I'm wondering if I can have a packageless () AS3 class call a private method on the main class in the file. For example:
package demo
{
public class MyDemoClass
{
var helper:FriendlyHelperClass = new FriendlyHelperClass(this)
}
private function methodToCall():void
{
...
}
}
public class FriendlyHelperClass
{
public function FriendlyHelperClass(demo:MyDemoClass)
{
demo.methodToCall()
}
}
The call to methodToCall() from FriendlyHelperClass will fail as it is a private member of the MyDemoClass. Is there any way to call the methodToCall() method from the FriendlyHelperClass without extending MyDemoClass.
Basically I'm looking for inner class functionality that Java has or some sort of C++ style friend class.
Short answer : no.
You can never access a private member from outside a class in ActionScript. What you could do is use a namespace instead of a private scope. This would allow to give access to some members to selected classes. This is the closest of a friend class that you will get in AS3.
I'm afraid that is not possible, but if you make the class dynamic, then you can edit it while the program is running, and possibly add some useful functions to it, to access the private functions. I haven't tried it though.
Dynamic classes
Without testing the code, and knowing what your full problem. you can try passing the functions you need into the embedded class as a callback. e.g.,
helper.methodToCallCallback = this.methodToCall;
then inside FriendlyHelperClass:
this.methodToCallCallback();
A database application that I'm currently working on, stores all sorts of settings in the database. Most of those settings are there to customize certain business rules, but there's also some other stuff in there.
The app contains objects that specifically do a certain task, e.g., a certain complicated calculation. Those non-UI objects are unit-tested, but also need access to lots of those global settings. The way we've implemented this right now, is by giving the objects properties that are filled by the Application Controller at runtime. When testing, we create the objects in the test and fill in values for testing (not from the database).
This works better, in any case much better than having all those objects need some global Settings object --- that of course effectively makes unit testing impossible :) Disadvantage can be that you sometimes need to set a dozen of properties, or that you need to let those properties 'percolate' into sub-objects.
So the general question is: how do you provide access to global application settings in your projects, without the need for global variables, while still being able to unit test your code? This must be a problem that's been solved 100's of times...
(Note: I'm not too much of an experienced programmer, as you'll have noticed; but I love to learn! And of course, I've already done research into this topic, but I'm really looking for some first-hand experiences)
You could use Martin Fowlers ServiceLocator pattern. In php it could look like this:
class ServiceLocator {
private static $soleInstance;
private $globalSettings;
public static function load($locator) {
self::$soleInstance = $locator;
}
public static function globalSettings() {
if (!isset(self::$soleInstance->globalSettings)) {
self::$soleInstance->setGlobalSettings(new GlobalSettings());
}
return self::$soleInstance->globalSettings;
}
}
Your production code then initializes the service locator like this:
ServiceLocator::load(new ServiceLocator());
In your test-code, you insert your mock-settings like this:
ServiceLocator s = new ServiceLocator();
s->setGlobalSettings(new MockGlobalSettings());
ServiceLocator::load(s);
It's a repository for singletons that can be exchanged for testing purposes.
I like to model my configuration access off of the Service Locator pattern. This gives me a single point to get any configuration value that I need and by putting it outside the application in a separate library, it allows reuse and testability. Here is some sample code, I am not sure what language you are using, but I wrote it in C#.
First I create a generic class that will models my ConfigurationItem.
public class ConfigurationItem<T>
{
private T item;
public ConfigurationItem(T item)
{
this.item = item;
}
public T GetValue()
{
return item;
}
}
Then I create a class that exposes public static readonly variables for the configuration item. Here I am just reading the ConnectionStringSettings from a config file, which is just xml. Of course for more items, you can read the values from any source.
public class ConfigurationItems
{
public static ConfigurationItem<ConnectionStringSettings> ConnectionSettings = new ConfigurationItem<ConnectionStringSettings>(RetrieveConnectionString());
private static ConnectionStringSettings RetrieveConnectionString()
{
// In .Net, we store our connection string in the application/web config file.
// We can access those values through the ConfigurationManager class.
return ConfigurationManager.ConnectionStrings[ConfigurationManager.AppSettings["ConnectionKey"]];
}
}
Then when I need a ConfigurationItem for use, I call it like this:
ConfigurationItems.ConnectionSettings.GetValue();
And it will return me a type safe value, which I can then cache or do whatever I want with.
Here's a sample test:
[TestFixture]
public class ConfigurationItemsTest
{
[Test]
public void ShouldBeAbleToAccessConnectionStringSettings()
{
ConnectionStringSettings item = ConfigurationItems.ConnectionSettings.GetValue();
Assert.IsNotNull(item);
}
}
Hope this helps.
Usually this is handled by an ini file or XML configuration file. Then you just have a class that reads the setting when neeed.
.NET has this built in with the ConfigurationManager classes, but it's quite easy to implement, just read text files, or load XML into DOM or parse them by hand in code.
Having config files in the database is ok, but it does tie you to the database, and creates an extra dependancy for your app that ini/xml files solve.
I did this:
public class MySettings
{
public static double Setting1
{ get { return SettingsCache.Instance.GetDouble("Setting1"); } }
public static string Setting2
{ get { return SettingsCache.Instance.GetString("Setting2"); } }
}
I put this in a separate infrastructure module to remove any issues with circular dependencies.
Doing this I am not tied to any specific configuration method, and have no strings running havoc in my applications code.