I'm struggling with a very basic Wicket issue. I'm trying to query a backend database, but can't get the results to display. Below is the code I'm using. currentQuery and currentResult is correctly updated after submission, but my SearchResults class is never rerendered with the new data in currentResults. I suppose that the results class just doesn't notice that the model has in fact been updated. I've been experimenting with modelChanged, but can't get it to work. I'm a bit new to Wicket, so I'm probably doing something fundamental completely wrong. Any help is much appreciated!
public class SearchPage extends WebPage {
Query currentQuery = new Query();
Result currentResult = new Result();
public SearchPage() {
add(new SearchForm("searchForm", new CompoundPropertyModel<Query>(currentQuery)));
add(new SearchResults("searchResults", new PropertyModel<List<Hit>>(currentResult, "hits")));
}
public void doSearch(Query Query) {
currentResult = getResults(query);
}
public class SearchForm extends Form<Query> {
public SearchForm(String id, CompoundPropertyModel<Query> model) {
super(id, model);
add(new TextField<String>("query"));
}
protected void onSubmit() {
super.onSubmit();
doSearch(currentQuery);
}
}
public class SearchResults extends WebMarkupContainer {
public SearchResults(String id, PropertyModel<List<Hit>> model) {
super(id, model);
add(new ListView<Hit>("hit", model) {
protected void populateItem(ListItem<Hit> item) {
item.add(new Label("column", item.getModelObject().getColumnValue("column")));
}
});
}
}
}
PropertyModel uses reflection to look up the named property on a given target object instance. When you constructed the PropertyModel, you passed it a specific instance of Result, i.e. the new Result() from SearchPage's constructor. The PropertyModel will continue to hold a reference to that same Result instance from render to render of this page, serializing the Result at the end and then deserializing the Result at the start of each new request cycle (page view). The fact that you later change the page's currentResult variable to reference a different Result instance does not affect which Result instance the PropertyModel uses to look up its model value. Your PropertyModel does not care what currentResult later refers to.
There are two possible solutions that I can think of off the top of my head.
Have the PropertyModel read hits from the actual current value of the Page's currentResult variable:
new PropertyModel<List<Hit>>(SearchPage.this, "currentResult.hits")
Use a LoadableDetachableModel to load hits once per request cycle/page view:
new LoadableDetachableModel<List<Hit>>()
{
protected Object load()
{
return getResults(currentQuery);
}
}
Note that a LoadableDetachableModel has to be detached at the end of the request cycle or it will never again call getObject() to recalculate the List<Hit>. That said, since your code shows you'd be using it as the default model of the SearchResults component, the SearchResults component would detach the model for you at the end of the request cycle automatically.
I got it working. This seems to be the offending row:
add(new SearchResults("searchResults", new PropertyModel<List<Hit>>(currentResult, "hits")));
The type of the PropertyModel, i.e. List<Hit>, must have been making the model static. So the only data SearchResults ever saw was the initial object, which was empty.
I changed the line to the below, and updated SearchResult accordingly.
add(new SearchResults("searchResults", new Model<Result>(currentResult, "hits")));
If anyone can explain this further, or feel that I'm incorrect, please comment! In any case, I'm marking my own answer as correct as this solved the problem.
Related
I am creating my web page with vaadin where I need to create same kind of blocks for different type for example need to show blocks having car details, so only car name would be different but the block design would be same with same label but different labels. I want to write generic code so that i can expand it for any car name, without adding it manually.
Attaching the code snippet which i am using where i am repeating my code for different type. Want to implement it dynamically.
private Grid<PresentableGenerateInputHeaders> winTSHeaderColumnsGrid;
private Grid<PresentableGenerateInputHeaders> fRHeaderColumnsGrid;
private ListDataProvider<PresentableGenerateInputHeaders> listDataProvider;
private List<PresentableGenerateInputHeaders> presentableGenerateInputHeaders = new ArrayList<>();
private void initWinTsGrid() {
listDataProvider = new ListDataProvider<>(presentableGenerateInputHeaders);
winTSHeaderColumnsGrid = new Grid<PresentableGenerateInputHeaders>(PresentableGenerateInputHeaders.class);
winTSHeaderColumnsGrid.setDataProvider(listDataProvider);
winTSHeaderColumnsGrid.setCaption(i18n.get("view.ruleDetails.general.csvHeaderColumns"));
winTSHeaderColumnsGrid.setStyleName("a-units");
winTSHeaderColumnsGrid.setWidth("450px");
winTSHeaderColumnsGrid.setItems(addGridValues(DataSource.WIN_TS, winTSHeaderColumnsGrid));
winTSHeaderColumnsGrid.getEditor().setEnabled(true);
winTSHeaderColumnsGrid.setColumnOrder("header", "count");
winTSHeaderColumnsGrid.sort("header");
winTSHeaderColumnsGrid.getEditor().addSaveListener((EditorSaveEvent<PresentableGenerateInputHeaders> event) -> {
event.getGrid().select(event.getBean());
selectedGapFillingCountWINTS.add(event.getBean());
});
}
private void initFRGrid() {
listDataProvider = new ListDataProvider<>(presentableGenerateInputHeaders);
fRHeaderColumnsGrid = new Grid<PresentableGenerateInputHeaders>(PresentableGenerateInputHeaders.class);
fRHeaderColumnsGrid.setDataProvider(listDataProvider);
fRHeaderColumnsGrid.setCaption(i18n.get("view.ruleDetails.general.csvHeaderColumns"));
fRHeaderColumnsGrid.setStyleName("a-units");
fRHeaderColumnsGrid.setWidth("450px");
fRHeaderColumnsGrid.setItems(addGridValues(DataSource.FR, fRHeaderColumnsGrid));
fRHeaderColumnsGrid.getEditor().setEnabled(true);
fRHeaderColumnsGrid.setColumnOrder("header", "count");
fRHeaderColumnsGrid.sort("header");
fRHeaderColumnsGrid.getEditor().addSaveListener((EditorSaveEvent<PresentableGenerateInputHeaders> event) -> {
event.getGrid().select(event.getBean());
selectedGapFillingCountFR.add(event.getBean());
});
}
You can change methods to be more generic by identifying all the parts you don't want to keep static, and moving those to be populated by method parameters instead. I.e. instead of
private void myMethod() {
grid.setCaption("myCaption");
}
you would write
private void myMethod(String caption) {
grid.setCaption(caption);
}
and then call it
myMethod("myCaption");
If you need to be outside of the whole class to be able to determine what the real values are, you can for example make the method public or pass on the necessary values in the class constructor.
public MyClass(String gridCaption) {
myMethod(gridCaption);
}
If there are a lot of values you need to set dynamically, you might consider using an object that contains all the necessary values instead.
public void myMethod(MyPojo pojo) {
grid.setCaption(pojo.getGridCaption());
}
In your example it looks like the generic values you want to pass are DataSource dataSource and whatever type of collection selectedGapFillingCountWINTS and selectedGapFillingCountFR happen to be, and the method should probably return the grid rather than set it directly to a class variable.
In my code I have a something like the following:
The wicket form:
public class MyForm extends Form<MyFormModel> {
public MyForm(String id){
super(id, new CompoundPropertyModel<MyFormModel>(new MyFormModel())
//add some labels from the CompoundPropertyModel
}
#Override
protected void onSubmit() {
setResponsePage(new NewPage(getModelObject()));
}
}
The form model:
public class MyFormModel extends LoadableDetachableModel<List<NotSerializableObject>> {
transient List<NotSerializableObject> list;
//Some labels with getters and setters for CompoundPropertyModel use
protected List<NotSerializableObject> load() {
//list = dbstuff.getstuff()
}
}
When the page is loaded with MyForm on it, the MyFormModel uses the load() function and tries to access the db before the form is submitted. I don't understand why because getModelObject() isn't called until the form is submitted and onSubmit() is called.
I understand that the CompoundPropertyModel and LoadableDetachableModel should be split to solve this but why does this not work? Why and from where is the load() function called?
Thanks for any help,
Martin
When the Form is displayed, each of the FormComponent s ask its Model for the value. The first call to getModelObject() (out of my head, have not done much wicket recently) is chained to the load() in the LoadableDetacheableModel.
It looks there is a component added to MyForm (your code snippet omits that part of code). If any of MyForm component access the model then the getModel().getObject() -> load() is called. Remeber that CompoundPropertyModel use also the getObject() on the inner model.
Since it is still not 100% clear when a LDM should be used I tried a simple memory test.
I created a DataView with a DataProvider that simply creates a list of few 100 entities with some big data inside (long String):
private class HeavyDataProvider implements IDataProvider<HeavyBean> {
#Override
public void detach() {
}
#Override
public Iterator<? extends HeavyBean> iterator(int first, int count) {
List<HeavyBean> l = newArrayList();
for (int i = 0; i < this.size(); i++) {
l.add(new HeavyBean());
}
return l.iterator();
}
#Override
public IModel<HeavyBean> model(HeavyBean heavyBean) {
return new CompoundPropertyModel<HeavyBean>(heavyBean);
}
#Override
public int size() {
return 500;
}
}
Using wicket's DebugBar is see this creates a Page with a size of 5MB. In the javadoc of DataProvider it is stated that the model return in above model method is usually a detachable one so I changed this method to:
#Override
public IModel<HeavyBean> model(final HeavyBean heavyBean) {
return new LoadableDetachableModel<HeavyBean>() {
#Override
protected HeavyBean load() {
return heavyBean;
}
};
}
Naively I was expecting the pagesize to be reduced in a big way now since the heavybeans will no longer be part of the model. Actual result: 5MB. Since the model will detach the heavyBean this must mean that something else still has a hold of it (DataView? Item?).
I saw other examples where DataView and DataProvider are combined in a similar fashion but for me it is unclear what the point is since it does not seem to make any difference regarding the pageSize/memory usage.
So, am I understanding/doing something wrong (likely) or are LDM's useless in DataProviders?
Side question (sorry), in which scenario would you use an LDM?
Your implementation of LDM is just plain wrong. It is holding a direct reference to the bean itself, and just returning it. This way, the bean will be serialized along the model, making it completely pointless.
You should do something like this:
#Override
public IModel<HeavyBean> model(final HeavyBean heavyBean) {
final Integer id = heavyBean.getId();
return new LoadableDetachableModel<HeavyBean>() {
#Override
protected HeavyBean load() {
return ServiceLocator.get(HeavyDao.class).get(id);
}
};
}
If you use the wicket-ioc module, the HeavyDao reference could be injected into the enclosing page/component.
I think Wicket is really easy to use, but you must understand the basics of Java serialization, or else you may end up with a very bloated http session.
For the LDM to work, you will have to actually detach the data in the detach() method. LDMs are meant to be used with databases, where you can restore / load the data on the next request with only the knowledge of an ID. So, in detach() you would trow away all data but the ID (or watever you need to relaod the data when needed) and in the load() (is this right? can't lock up the api right now) you will restore the data.
Hope that helps.
I have a method where I want to factor out some code into its own method
This is what I have:
public class TD0301AssignmentForm extends Form {
public TD0301AssignmentForm(TD0301AssignmentDAO dao, STKUser authenticatedUser) {
this.dao = dao;
this.authenticatedUser = authenticatedUser;
}
public Object insert(HttpServletRequest request) {
TD0301Assignment tdas = new TD0301Assignment();
TD0301Assignment tdas_orig = null;
Date dateNow = new Date();
try {
// Get the inuput from HTML form
tdas.setCalc_num(FormUtil.getFieldValue(request, FIELD_CALC_NUM));
processDate(request, tdas);
tdas.setCalc_dept(FormUtil.getFieldValue(request, FIELD_CALC_DEPT));
tdas.setYear_oi(Integer.toString(DateUtil.getIntYear(dateNow)));
processCalcSafetyRequirements(request, tdas);
...etc...
if (isSucces()) {
// Instantiate a base work flow instance!
WorkflowInstance wfi = new WorkflowInstance();
WorkflowInstanceDAO wfiDAO = new WorkflowInstanceDAO();
wfi.setWorkflow_class_id(tdas.getCalc_level());
wfi.setStarted_by(authenticatedUser.getBadge());
wfi.setStatus("0");
wfi.setLast_date(dateNow);
// Insert the WorkFlowInstance into the database, db sets returned sequence number into the wfi object.
wfiDAO.insert(wfi, authenticatedUser);
// Insert the TD0301Assignment into the db
tdas.setWorkflow_instance_id(wfi.getWorkflow_instance_id());
}
I'd like to remove the WorkflowInstance code out into its own method (still in this Class) like this:
if (isSucces()) {
insertWorkFlowInstance(request, tdas);
tdas.setWorkflow_instance_id(wfi.getWorkflow_instance_id());
but wfi is now marked by Eclipse as not available. Should I do something like this to fix the error so that I can still get the wfi.getWorkflow_instance_id() in the isSuccess block above? I know it removes the error, but I am trying to apply best practices.
public class TD0301AssignmentForm extends Form {
private WorkflowInstance wfi = new WorkflowInstance();
private WorkflowInstanceDAO wfiDAO = new WorkflowInstanceDAO();
Instance variables ("properties" or "fields") are not necessarily the way to go if they're not used throughout the entire class.
Variables should have the smallest scope possible--this makes code easier to reason about.
With some noise elided, and also guessing, it seems like the WorkflowInstance and WorkflowInstanceDao could be localized (names changed to match Java conventions):
public class TD0301AssignmentForm extends Form {
public Object insert(HttpServletRequest request) {
TD0301Assignment tdas = new TD0301Assignment();
try {
tdas.setCalcNum(FormUtil.getFieldValue(request, FIELD_CALC_NUM));
processDate(request, tdas);
tdas.setCalcDept(FormUtil.getFieldValue(request, FIELD_CALC_DEPT));
tdas.setYearOi(Integer.toString(DateUtil.getIntYear(dateNow)));
processCalcSafetyRequirements(request, tdas);
if (isSuccess()) {
WorkflowInstance wf = buildWorkflow(tdas);
tdas.setWorkflowInstanceId(wf.getId());
}
}
}
private buildWorkflow(TD0301Assignment tdas) {
WorkflowInstance wfi = new WorkflowInstance();
wfi.setWorkflowClassId(tdas.getCalcLevel());
wfi.setStartedBy(authenticatedUser.getBadge());
wfi.setStatus("0");
wfi.setLastDate(new Date());
WorkflowInstanceDao wfiDao = new WorkflowInstanceDao();
wfiDao.insert(wfi, authenticatedUser);
}
}
Whether or not this is appropriate depends on how/if the WorkflowInstance is used in the rest of the method snippet you show. The DAO is almost certainly able to be localized.
As methods become smaller and easier to think about, they become more testable.
For example, buildWorkflow is almost easy to test, except that the DAO is instantiated "manually". This means that testing the method will either (a) depend on having a working DAO layer, or (b) it must be mocked by a framework that can mock static utility methods (several can).
Without seeing all your code it's not easy to see exactlywhat you are trying to achieve. The reason eclipse is complaining is because it no longer has a wfi instance to play with because you've moved its local instance into your method, but creating another wfi instance is not likely to be your answer.
To get this working change the wfi to be class local and either use it's id directly or return wfi.getWorkflow_instance_id() from insertWorkFlowInstance() and then pass that value into tdas.setWorkflow_instance_id()
I used PropertyModel as the part of my DropDownChoice as following:
List<String> choices = Arrays.asList(new String[] { "Library", "School Office", "Science Dept" });
String selected = "Library";
DropDownChoice<String> serviceDDC =
new DropDownChoice<String>("service", new PropertyModel(this, "choices.0"), choices);
Somehow I've got this exception thown:
caused by: org.apache.wicket.WicketRuntimeException: No get method defined for class: class com.samoo.tool.pages.CreatePrintingJob expression: choices
at org.apache.wicket.util.lang.PropertyResolver.getGetAndSetter(PropertyResolver.java:481)
at org.apache.wicket.util.lang.PropertyResolver.getObjectAndGetSetter(PropertyResolver.java:332)
at org.apache.wicket.util.lang.PropertyResolver.getObjectAndGetSetter(PropertyResolver.java:242)
at org.apache.wicket.util.lang.PropertyResolver.getValue(PropertyResolver.java:95)
at org.apache.wicket.model.AbstractPropertyModel.getObject(AbstractPropertyModel.java:130)
at org.apache.wicket.Component.getDefaultModelObject(Component.java:1724)
....
I know that there's something wrong with the expression. I've been trying different parameter inputs but it still doesn't work. Could anyone help?
Since you're using PropertyModel(this, "choices.0"), Wicket is trying to find a property named choices via reflection through a method getChoices() of the class declaring the PropertyModel. This method doesn't seem to exist in com.samoo.tool.pages.CreatePrintingJob, as the exception is stating.
Also, if that 0 is an index, you should be accessing it with the [index] expression, as this JIRA issue suggests: PropertyModel does not support index only property ("[0]")
However, it seems you want to initialize the DropDownChoice to the first element of choices. But What Wicket will do if you set the DropDownChoice's Model to PropertyModel(this, "choices.[0"]) will be mapping the selection of this DropDownChoice in the following way:
At form rendering time to present the (pre)selected choice, it will use the first element in the choices list.
At form submission time to store the user selected value, it will store the selection in the first position of the choices list.
Summarising, the backing object representing the DropDownChoice's selection would be the first element in the choices list.
So, you'll probably want to use a whole different Model, independent from the choices list, for the backing object representing the DDC's selection.
List<String> choices = Arrays.asList(new String[] { "Library", "School Office",
"Science Dept" });
String selected = "Library";
IModel dropdownModel = new Model<String>(choices[0]);
DropDownChoice<String> serviceDDC =
new DropDownChoice<String>("service", dropdownModel, choices);
You might find the following links useful:
Using the DropDownChoice component
Working with Wicket Models
you are declaring choices inside the method, in order to get the PropertyModel to work you need to declare it on a class level not on a method level. As #Xavi López pointed out the espression is not corret you nedd to use choices.[0]
It is good idea to use IModel instead of PropertyMOdel.PropertyModel has big problems in refactoring. In my cases I did it and the problems solved properly.Also I have override the toString() of my Topic object.
topicDropDown = new DropDownChoice<Topic>("topicOptions", new IModel<Topic>() {
#Override
public Topic getObject() {
return top;
}
#Override
public void setObject(Topic t) {
top = t;
}
#Override
public void detach() {
}
}, new LoadableDetachableModel<List<Topic>>() {
#Override
protected List<Topic> load() {
List<Topic> topics = top.getAllTopics();
return topics;
}
});