I'm working with the multiple row selection to give a user ability to delete the selecting records. According to the PDF documentation, and the ShowCase Labs, I must use the code translated to the Java like that:
final DataTable = new DataTable();
...
// (1)
dataTable.setSelectionMode("multiple");
// (2)
dataTable.setValueExpression("selection", createValueExpression(DbeBean.class, "selection", Object[].class));
// (3)
dataTable.setValueExpression("rowKey", createValueExpression("#{" + VARIABLE + ".indexKey}", Object.class));
...
final ClientBehaviorHolder dataTableAsHolder = dataTable;
...
// (4)
dataTableAsHolder.addClientBehavior("rowSelect", createAjaxBehavior(createMethodExpression(metaData.controllerBeanType, "onRowSelect", void.class, new Class<?>[] {SelectEvent.class})));
multiple - This line features the multiple selection, works fine visually at the front-end.
selection - Being invoked, the #{dbeBean.selection} is really bound and the public void setSelection(T[] selection) is only invoked.
rowKey - Being invoked, works fine, the getIndexKey() is invoked and returns the necessary result.
rowSelect - This event handler is invoked too, DbeBean.onRowSelect(SelectEvent e).
I also use lazy data model (I don't really believe it may be the reason but who knows?; by the way, it returns List<T> though setSelection() requires T[] -- why it's like that?):
public abstract class AbstractLazyDataSource<T extends IIndexable<K>, K> extends LazyDataModel<T> {
...
#Override
public final List<T> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String, String> filters) {
...
final IResultContainer<T> resultContainer = getData(querySpecifier);
final List<T> data = resultContainer.getData();
setRowCount(resultContainer.getTotalEntitiesCount());
return getPage(data, first, pageSize);
}
...
#Override
public final K getRowKey(T object) {
return object.getIndexKey(); // T instanceof IIndexable<K>, have to return a unique ID
}
...
However, the handlers do not work as they are expected to work. Please help me to understand why (2) DbeBean.setSelection(T[] selection) & (4) DbeBean.onRowSelect(SelectEvent e) get only the null value: T[] selection = null, and SelectEvent: e.getObject = null, respectively. What am I doing wrong?
Thanks in advance.
PrimeFaces 3.2
Mojarra 2.1.7
I've got it to work: I simply removed the rowKey property during to the dynamic p:dataTable creation (DataTable), and simply overloaded getRowData in lazy data model. Now it works.
Related
Later Edit: I noticed that by returning one of the options in ValueProvider's apply method leads to having the check mark present, but appears to show the previous select too. I.e. if the current and previous values are distinct, two check marks are shown.
I am having troubles with ComboBox binding. I cannot get the com.vaadin.flow.data.binder.Binder properly select an option inside the combobox - i.e. tick the check mark in the dropdown.
My binder is a "generic", i.e. I am using it along with a Map, and I provide dynamic getters/setters for various map keys. So, consider Binder<Map>, while one of the properites inside the Map should be holding a Person's id.
ComboBox<Person> combobox = new ComboBox<>("Person");
List<Person> options = fetchPersons();
combobox.setItems(options);
combobox.setItemLabelGenerator(new ItemLabelGenerator<Person>() {
#Override
public String apply(final Person p) {
return p.getName();
}
});
binder.bind(combobox, new ValueProvider<Map, Person>() {
#Override
public Person apply(final Map p) {
return new Person((Long)p.get("id"), (String)p.get("name"));
}
}, new Setter<Map, Person>() {
#Override
public void accept(final Map bean, final Person p) {
bean.put("name", p.getName());
}
});
Wondering what could I possibly do wrong...
Later edit: Adding a screenshot for the Status ComboBox which has a String for caption and Integer for value.
Your problem is that you are creating a new instance in your binding, which is not working. You probably have some other bean, (I say here Bean) where Person is a property. So you want to use Binder of type Bean, to bind ComboBox to the property, which is a Person. And then populate your form with the Bean by using e.g. binder.readBean(bean). Btw. using Java 8 syntax makes your code much less verbose.
Bean bean = fetchBean();
Binder<Bean> binder = new Binder();
ComboBox<Person> combobox = new ComboBox<>("Person");
List<Person> options = fetchPersons();
combobox.setItems(options);
combobox.setItemLabelGenerator(Person::getName);
binder.forField(combobox).bind(Bean::getPerson, Bean::setPerson);
binder.readBean(bean);
I'm using a Grid in Vaadin 14. The grid is in multi-selection mode.
The selection handler takes a couple of seconds to complete and I'm calling setItems(...) at the end to update the items in the grid.
When the user selects another row while the previous selection handler is still running, I get an "Unknown key" error similar to the one described in https://github.com/vaadin/vaadin-grid-flow/issues/322, even though the new set of items still contains the selected item (another object instance but same according to equals()). This seems to be because the keys in the KeyMapper have already been changed due to setItems(), so the key coming from the client is not present anymore.
Is there a way to work around this, for example by disabling selection while the previous request is in progress?
UPDATE
To work around this Vaadin bug, I'm also calling setPageSize() with the exact number of items as argument. But it seems the same problem occurs even if I don't call setPageSize(), so it's probably due to setItems().
Do not change the grids items inside a SelectionListener.
You can still do all the things you wanted, but setting the items anew is not actually needed. In fact it will only create problems as you are experiencing now.
While working at this answer, I realized you will need to do your own Checkbox Column in order to be able to do actions for the one item that was just "selected", instead of removing all then add all selected ones (because much better performance). Here is how that could look.
// in my code samples, a `Foo` item can have many `Bar` items. The grid is of type Bar.
Grid.Column customSelectionColumn = grid.addComponentColumn(item -> {
Checkbox isSelected = new Checkbox();
isSelected.setValue(someParentFoo.getBars().contains(item));
isSelected.addValueChangeListener(event -> {
boolean newSelectedValue = event.getValue();
if(newSelectedValue){
someParentFoo.getBars().add(item)
} else {
someParentFoo.getBars().remove(item);
}
fooRepository.save(someParentFoo);
});
});
// make a Checkbox that selects all in the header
Checkbox toggleSelectAll = new Checkbox();
toggleSelectAll.addValueChangeListener(event -> {
if(event.getValue()){
someParentFoo.getBars().addAll(allGridItems);
} else {
someParentFoo.getBars().removeAll(allGridItems);
}
fooRepository.save(someParentFoo);
grid.getDataProvider().refreshAll(); // updates custom checkbox value of each item
});
gridHeaderRow.getCell(customSelectionColumn).setComponent(toggleSelectAll);
I solved this problem. Vaadin use data as key in HashMap. You need calc hashCode use immutable data fields. For example
public class TestData {
private int id;
private String name;
public TestData(int id) {
this.id = id;
}
#Override
public int hashCode() {
return Objects.hash(id);
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
I am trying to write a custom converter for a nested object so that this object gets saved as string in Neo4j database.
I am using #Convert annotation on my field and passing ImageConverter.class which is my AttributeConverter class.
Everything works fine as expected and I am able to save string representation of Image class in Neo4j db.
However, now instead of single image I want to have List<Image> as my nested field. In this case, putting #Convert(ImageConverter.class) doesn't work.
I see that there is a class called ConverterBasedCollectionConverter which gets used when I have a field of type List<LocalDateTime.
However, I couldn't find any exammples on how to use this class in case of custom converters.
Please can anyone help me with this or if there is any other approach to use custom converter on field of type List.
I am using Neo4j (version 3.4.1) and Spring-data-neo4j (5.0.10.RELEASE) in my application. I am also using OGM.
PS: I am aware that it is advised to store nested objects as separate node establishing a relationship with parent object. However, my use case demands that the object be stored as string property and not as separate node.
Regards,
V
It is not so difficult as I assumed it would be.
Given a class (snippet)
#NodeEntity
public class Actor {
#Id #GeneratedValue
private Long id;
#Convert(MyImageListConverter.class)
public List<MyImage> images = new ArrayList<>();
// ....
}
with MyImage as simple as can be
public class MyImage {
public String blob;
public MyImage(String blob) {
this.blob = blob;
}
public static MyImage of(String value) {
return new MyImage(value);
}
}
and a converter
public class MyImageListConverter implements AttributeConverter<List<MyImage>, String[]> {
#Override
public String[] toGraphProperty(List<MyImage> value) {
if (value == null) {
return null;
}
String[] values = new String[(value.size())];
int i = 0;
for (MyImage image : value) {
values[i++] = image.blob;
}
return values;
}
#Override
public List<MyImage> toEntityAttribute(String[] values) {
List<MyImage> images = new ArrayList<>(values.length);
for (String value : values) {
images.add(MyImage.of(value));
}
return images;
}
}
will print following debug output on save that I think is what you want:
UNWIND {rows} as row CREATE (n:Actor) SET n=row.props RETURN row.nodeRef as ref, ID(n) as id, {type} as type with params {type=node, rows=[{nodeRef=-1, props={images=[blobb], name=Jeff}}]}
especially the images part.
Test method for this looks like
#Test
public void test() {
Actor jeff = new Actor("Jeff");
String blobValue = "blobb";
jeff.images.add(new MyImage(blobValue));
session.save(jeff);
session.clear();
Actor loadedActor = session.load(Actor.class, jeff.getId());
assertThat(loadedActor.images.get(0).blob).isEqualTo(blobValue);
}
I am came up with a solution to my problem. So, in case you want another solution along with the solution provided by #meistermeier, you can use the below code.
public class ListImageConverter extends ConverterBasedCollectionConverter<Image, String>{
public ListImageConverter() {
super(List.class, new ImageConverter());
}
#Override
public String[] toGraphProperty(Collection<Image> values) {
Object[] graphProperties = super.toGraphProperty(values);
String[] stringArray = Arrays.stream(graphProperties).toArray(String[]::new);
return stringArray;
}
#Override
public Collection<Image> toEntityAttribute(String[] values) {
return super.toEntityAttribute(values);
}
}
ImageConverter class just implements AttributeConverter<Image, String> where I serialize and deserialize my Image object to/from json.
I chose to go with this approach because I had Image field in one object and List<Image> in another object. So just by changing #Convert(ListImageConverter.class) to #Convert(ImageConverter.class) I was able to save list as well as single object in Neo4j database.
Note: You can skip overriding toEntityAttribute method if you want. It doesn't add much value.
However you have to override toGraphProperty as within Neo4j code it checks for presence of declared method with name toGraphProperty.
Hope this helps someone!
Regards,
V
We have a problem making asList() method sortable.
We thought we could do this by just extending the View class and override the asList method but realized that View class has a private constructor so we could not do this.
Our other attempt was to fork the Google Dataflow code on github and modify the PCollectionViews class to return a sorted list be using the Collections.sort method as shown in the code snippet below
#Override
protected List<T> fromElements(Iterable<WindowedValue<T>> contents) {
Iterable<T> itr = Iterables.transform(
contents,
new Function<WindowedValue<T>, T>() {
#SuppressWarnings("unchecked")
#Override
public T apply(WindowedValue<T> input){
return input.getValue();
}
});
LOG.info("#### About to start sorting the list !");
List<T> tempList = new ArrayList<T>();
for (T element : itr) {
tempList.add(element);
};
Collections.sort((List<? extends Comparable>) tempList);
LOG.info("##### List should now be sorted !");
return ImmutableList.copyOf(tempList);
}
Note that we are now sorting the list.
This seemed to work, when run with the DirectPipelineRunner but when we tried the BlockingDataflowPipelineRunner, it didn't seem like the code change was being executed.
Note: We actually recompiled the dataflow used it in our project but this did not work.
How can we be able to achieve this (as sorted list from the asList method call)?
The classes in PCollectionViews are not intended for extension. Only the primitive view types provided by View.asSingleton, View.asSingleton View.asIterable, View.asMap, and View.asMultimap are supported.
To obtain a sorted list from a PCollectionView, you'll need to sort it after you have read it. The following code demonstrates the pattern.
// Assume you have some PCollection
PCollection<MyComparable> myPC = ...;
// Prepare it for side input as a list
final PCollectionView<List<MyComparable> myView = myPC.apply(View.asList());
// Side input the list and sort it
someOtherValue.apply(
ParDo.withSideInputs(myView).of(
new DoFn<A, B>() {
#Override
public void processElement(ProcessContext ctx) {
List<MyComparable> tempList =
Lists.newArrayList(ctx.sideInput(myView));
Collections.sort(tempList);
// do whatever you want with sorted list
}
}));
Of course, you may not want to sort it repeatedly, depending on the cost of sorting vs the cost of materializing it as a new PCollection, so you can output this value and read it as a new side input without difficulty:
// Side input the list, sort it, and put it in a PCollection
PCollection<List<MyComparable>> sortedSingleton = Create.<Void>of(null).apply(
ParDo.withSideInputs(myView).of(
new DoFn<Void, B>() {
#Override
public void processElement(ProcessContext ctx) {
List<MyComparable> tempList =
Lists.newArrayList(ctx.sideInput(myView));
Collections.sort(tempList);
ctx.output(tempList);
}
}));
// Prepare it for side input as a list
final PCollectionView<List<MyComparable>> sortedView =
sortedSingleton.apply(View.asSingleton());
someOtherValue.apply(
ParDo.withSideInputs(sortedView).of(
new DoFn<A, B>() {
#Override
public void processElement(ProcessContext ctx) {
... ctx.sideInput(sortedView) ...
// do whatever you want with sorted list
}
}));
You may also be interested in the unsupported sorter contrib module for doing larger sorts using both memory and local disk.
We tried to do it the way Ken Knowles suggested. There's a problem for large datasets. If the tempList is large (so sort takes some measurable time as it's proportion to O(n * log n)) and if there are millions of elements in the "someOtherValue" PCollection, then we are unecessarily re-sorting the same list millions of times. We should be able to sort ONCE and FIRST, before passing the list to the someOtherValue.apply's DoFn.
I am trying to create a conditional ContractResolver so that I can control the serialization differently depending on the web request/controller action.
For example in my User Controller I want to serialize all properties of my User but some of the related objects I might only serialize the primitive types. But if I went to my company controller I want to serialize all the properties of the company but maybe only the primitive ones of the user (because of this I don't want to use dataannotations or shouldserialize functions.
So looking at the custom ContractResolver page i created my own.
http://james.newtonking.com/projects/json/help/index.html?topic=html/ContractResolver.htm
It looks like this
public class IgnoreListContractResolver : DefaultContractResolver
{
private readonly Dictionary<string, List<string>> IgnoreList;
public IgnoreListContractResolver(Dictionary<string, List<string>> i)
{
IgnoreList = i;
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
List<JsonProperty> properties = base.CreateProperties(type, memberSerialization).ToList();
if(IgnoreList.ContainsKey(type.Name))
{
properties.RemoveAll(x => IgnoreList[type.Name].Contains(x.PropertyName));
}
return properties;
}
}
And then in my web api controller action for GetUsers i do this
public dynamic GetUsers()
{
List<User> Users = db.Users.ToList();
List<string> RoleList = new List<string>();
RoleList.Add("UsersInRole");
List<string> CompanyList = new List<string>();
CompanyList.Add("CompanyAccesses");
CompanyList.Add("ArchivedMemberships");
CompanyList.Add("AddCodes");
Dictionary<string, List<string>> IgnoreList = new Dictionary<string, List<string>>();
IgnoreList.Add("Role", RoleList);
IgnoreList.Add("Company", CompanyList);
GlobalConfiguration
.Configuration
.Formatters.JsonFormatter
.SerializerSettings
.ContractResolver = new IgnoreListContractResolver(IgnoreList);
return new { List = Users, Status = "Success" };
}
So when debugging this I see my contract resolver run and it returns the correct properties but the Json returned to the browser still contains entries for the properties I removed from the list.
Any ideas what I am missing or how I can step into the Json serialization step in webapi controllers.
*UPDATE**
I should add that this is in an MVC4 project that has both MVC controllers and webapi controllers. The User, Company, and Role objects are objects (created by code first) that get loaded from EF5. The controller in question is a web api controller. Not sure why this matters but I tried this in a clean WebApi project (and without EF5) instead of an MVC project and it worked as expected. Does that help identify where the problem might be?
Thanks
*UPDATE 2**
In the same MVC4 project I created an extension method for the Object class which is called ToJson. It uses Newtonsoft.Json.JsonSerializer to serialize my entities. Its this simple.
public static string ToJson(this object o, Dictionary<string, List<string>> IgnoreList)
{
JsonSerializer js = JsonSerializer.Create(new Newtonsoft.Json.JsonSerializerSettings()
{
Formatting = Formatting.Indented,
DateTimeZoneHandling = DateTimeZoneHandling.Utc,
ContractResolver = new IgnoreListContractResolver(IgnoreList),
ReferenceLoopHandling = ReferenceLoopHandling.Ignore
});
js.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
var jw = new StringWriter();
js.Serialize(jw, o);
return jw.ToString();
}
And then in an MVC action i create a json string like this.
model.jsonUserList = db.Users.ToList().ToJson(IgnoreList);
Where the ignore list is created exactly like my previous post. Again I see the contract resolver run and correctly limit the properties list but the output json string still contains everything (including the properties I removed from the list). Does this help? I must be doing something wrong and now it seems like it isn't the MVC or web api framework. Could this have anything to do with EF interactions/ proxies /etc. Any ideas would be much appreciated.
Thanks
*UPDATE 3***
Process of elimination and a little more thorough debugging made me realize that EF 5 dynamic proxies were messing up my serialization and ContractResolver check for the type name match. So here is my updated IgnoreListContractResolver. At this point I am just looking for opinions on better ways or if I am doing something terrible. I know this is jumping through a lot of hoops just to use my EF objects directly instead of DTOs but in the end I am finding this solution is really flexible.
public class IgnoreListContractResolver : CamelCasePropertyNamesContractResolver
{
private readonly Dictionary<string, List<string>> IgnoreList;
public IgnoreListContractResolver(Dictionary<string, List<string>> i)
{
IgnoreList = i;
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
List<JsonProperty> properties = base.CreateProperties(type, memberSerialization).ToList();
string typename = type.Name;
if(type.FullName.Contains("System.Data.Entity.DynamicProxies.")) {
typename = type.FullName.Replace("System.Data.Entity.DynamicProxies.", "");
typename = typename.Remove(typename.IndexOf('_'));
}
if (IgnoreList.ContainsKey(typename))
{
//remove anything in the ignore list and ignore case because we are using camel case for json
properties.RemoveAll(x => IgnoreList[typename].Contains(x.PropertyName, StringComparer.CurrentCultureIgnoreCase));
}
return properties;
}
}
I think it might help if you used Type instead of string for the ignore list's key type. So you can avoid naming issues (multiple types with the same name in different namespaces) and you can make use of inheritance. I'm not familiar with EF5 and the proxies, but I guess that the proxy classes derive from your entity classes. So you can check Type.IsAssignableFrom() instead of just checking whether typename is a key in the ignore list.
private readonly Dictionary<Type, List<string>> IgnoreList;
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
List<JsonProperty> properties = base.CreateProperties(type, memberSerialization).ToList();
// look for the first dictionary entry whose key is a superclass of "type"
Type key = IgnoreList.Keys.FirstOrDefault(k => k.IsAssignableFrom(type));
if (key != null)
{
//remove anything in the ignore list and ignore case because we are using camel case for json
properties.RemoveAll(x => IgnoreList[key].Contains(x.PropertyName, StringComparer.CurrentCultureIgnoreCase));
}
return properties;
}
Then the ignore list must be created like this (I also used the short syntax for creating the list and dictionary):
var CompanyList = new List<string> {
"CompanyAccesses",
"ArchivedMemberships",
"AddCodes"
};
var IgnoreList = new Dictionary<Type, List<string>> {
// I just replaced "Company" with typeof(Company) here:
{ typeof(Company), CompanyList }
};
Be aware that, if you use my code above, adding typeof(object) as the first key to the ignore list will cause this entry to be matched every time, and none of your other entries will ever be used! This happens because a variable of type object is assignable from every other type.