Need help with iteration problem (adding an Object to a List for every instance of that Object)

[Matt Kohanek]

My end goal is to load a List with every instance of the ProjectHolder Object the following code creates, but I keep ending up with a List that has the last object the following code creates multiple times.

So I have a ProjectHolder class that has two variables -
String projectName;
List<String> devicesList;

Then I have a Nodes class to load this Object with Values. I know this code does load the Object with values, because I have System.out.println() in every for loop

		@PostConstruct
	public void loadValues(){
		
		//start set the projectName
		MeasurementProjectCollectionXMLAO access = new MeasurementProjectCollectionXMLAO();  
		ProjectHttpClient method = new ProjectHttpClient();
        MeasurementProjectCollection measurementProjectCollection = null;
        ProjectHolder projectHolder = new ProjectHolder();
        
        //sets measurementProjectCollection to the xml received from web service
		try {
			measurementProjectCollection = access.readXML(method.Response(null));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	        
			for (MeasurementProject measurementProject : measurementProjectCollection.getMeasurementProjects()){ 
			       projectHolder.setProjectName(measurementProject.getName());
			       url = measurementProject.getProjectId();		
			       System.out.println("Value of ProjectName "+projectHolder.getProjectName());
			       
						       //setting the deviceList values
						       if(measurementProject.getDevices() != null){
						    	   
						       //clear the previous values first
						       projectHolder.clearDevicesList();
						       
								MeasurementProjectXMLAO allow = new MeasurementProjectXMLAO();
								MeasurementProject project  = null;
								
								//sets project to the xml received from web service
								try {
									project = allow.readXML(method.GetMethod(url));
								} catch (Exception e) {
									// TODO Auto-generated catch block
									e.printStackTrace();
								}
								
								for (ProjectDevice projectDevice : project.getDevices()){ 
								       projectHolder.devicesList.add(projectDevice.getDeviceId());
								       System.out.println("Value of deviceList "+projectHolder.getDevicesList().toString());
								}
								
						       }
						     //end setting the deviceList
			projects.add(projectHolder);
			}
		//end set projectName	
	}

Basically this sets the projectName to the projectName that is stored on a web service, and if there are any devices for this project, it add those device(s) to the deviceList. I am sure that is all working fine, because when I call this loadValues() method, it one by one prints out the projectNames, and if there are any devices, it will print those out as well. Here is a short sample of the print out:

Value of ProjectName PropProp2
Value of ProjectName WSN Pond Measurements
Value of deviceList [WSN-Module-8F3A-D247-4B99]
Value of ProjectName Propertiestest

At the end of the code there you can see I have projects.add(projectHolder); at the end of the for loop. This is the for loop that it is inside of: for (MeasurementProject measurementProject : measurementProjectCollection.getMeasurementProjects())

Its saying for every project in the projectCollection, perform all the operations to set the variables, and then at the end add the newly formed object to the List<ProjectHolder> List;
However what is happening it seems is that it is adding the same Object 33 times, instead of 33 unique Objects. so my projects List<ProjectHolder> contains 33 of the same Object. Can anyone tell me how I can fix this? I need it to add the new object to the List<ProjectHolder> projects; list for every version this method creates.

That is unless I am wrong about my interpretation of this output. I have a print method to print out the value of the projects List. It prints this:

Printing value of projects List [nodesContainer.ProjectHolder@186c6b2, nodesContainer.ProjectHolder@186c6b2, ......etc 31 more time]

Those are all the same Objects in that list right?

[Rob Spoor]

You only create one ProjectHolder instance, outside the for-loop. Move that line to just inside the for-loop instead.

[Matt Kohanek]

Thanks Rob, that was exactly it. I don't know how long it would have taken me to figure that one little detail out.