CODEWITHSUNDEEP
jsf-2composite-componentstate-saving
toxich
toxich

Reputation: 41

How to avoid sharing of values stored in StateHelper of composite components placed inside PrimeFaces datatable?

My composite components share values stored in StateHelper when placed inside PrimeFaces DataTable. The most of examples about keeping component state that I've seen suggest to use getStateHelper().put()/eval() methods of UINamingContainer. I do use these methods but without luck. How to do that properly? (currently I use workaround described in the end of this post)

To illustrate the issue I've created click counter based on PrimeFaces commandLink component. In the example below two counters that are outside of dataTable work as expected. But all counters that appear inside dataTable share the same counter value (clicking on any one of them continues common value).

Update: I've figured out that to allow sorting (for example) to work correctly inside datatable I need to bind my component to certain raw somehow. And "shared" state helper allows to do exactly that. So now I specify row key as an attribute and have updated methods to store state. There is no question if this way is correct.

Update for counterLink.xhtml:

<composite:interface componentType="CounterLink2Component">
    <composite:attribute name="key" type="java.io.Serializable"/>
</composite:interface>

And CounterLinkComponent.java now is:

@FacesComponent("CounterLinkComponent")
public class CounterLinkComponent extends UINamingContainer {

    private enum PropertyKeys {
        COUNTER_VALUE
    }

    public void count() {
        storeInstanceValue(PropertyKeys.COUNTER_VALUE.toString(), getCounterValue() + 1);
    }

    public Integer getCounterValue(){
        return (Integer) evalInstanceValue(PropertyKeys.COUNTER_VALUE.toString(), 0);
    }

    private Serializable getKeyAttr() {
        return (Serializable) getAttributes().get("key");
    }

    private void storeInstanceValue(String key, Object value) {
        Serializable subkey = getKeyAttr();
        if (subkey == null) {
            getStateHelper().put(key, value);
        }  else {
            getStateHelper().put(subkey, key, value);
        }
    }

    private Object getInstanceValue(String key) {
        Serializable subkey = getKeyAttr();
        if (subkey == null) {
            return getStateHelper().eval(key);
        } else {
            return ((Map) getStateHelper().eval(subkey, Collections.emptyMap())).get(key);
        }
    }

    private Object evalInstanceValue(String key, Object _default) {
        Object result = getInstanceValue(key);
        return result != null ? result : _default;
    }
}

Original example:

Primefaces 5.0, Glassfish 4.

counterLink.xhtml:

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:composite="http://java.sun.com/jsf/composite"
      xmlns:p="http://primefaces.org/ui">

<composite:interface componentType="CounterLinkComponent">
</composite:interface>
<composite:implementation>
    <p:commandLink action="#{cc.count()}" partialSubmit="true" update="@this">
        <h:outputText value="#{cc.counterValue}"/>
    </p:commandLink>
</composite:implementation>
</html>

CounterLinkComponent.java:

import javax.faces.component.FacesComponent;
import javax.faces.component.UINamingContainer;
import java.io.Serializable;

@FacesComponent("CounterLinkComponent")
public class CounterLinkComponent extends UINamingContainer {

    private enum PropertyKeys {
        COUNTER_VALUE
    }

    public void count() {
        getStateHelper().put(PropertyKeys.COUNTER_VALUE, getCounterValue() + 1);
    }

    public Integer getCounterValue(){
        return (Integer) getStateHelper().eval(PropertyKeys.COUNTER_VALUE, 0);
    }
}

Usage example:

<h:form>
    <p:panelGrid columns="1">
        <cmp:counterLink/>
        <cmp:counterLink/>

        <p:dataTable var="item" value="#{counterLinkStoreBean.itemList}">
            <p:column headerText="Name">
                #{item.name}
            </p:column>

            <p:column headerText="Counter">
                <cmp:counterLink/>
            </p:column>
        </p:dataTable>
    </p:panelGrid>
</h:form>

Backing bean for this example (just creates several items):

@Named
@ViewScoped
public class CounterLinkStoreBean implements Serializable {

    private List<Item> itemList;

    @PostConstruct
    private void init() {
        itemList = new ArrayList<Item>();
        itemList.add(new Item("Test 1"));
        itemList.add(new Item("Test 2"));
        itemList.add(new Item("Test 3"));
    }

    public List<Item> getItemList() {
        return itemList;
    }

    public static class Item {
        private final String name;

        public Item(String name) {
            this.name = name;
        }

        public String getName() {
            return name;
        }
    }
}

In my case I can use workaround storing values in a map with component clientId as a secondary key:

private void storeInstanceValue(Serializable key, Object value) {
    getStateHelper().put(key, getClientId(), value);
}

private Object getInstanceValue(Serializable key) {
    return ((Map)getStateHelper().eval(key, Collections.emptyMap())).get(getClientId());
}

Is there more natural solution?

Upvotes: 4

Views: 1548

Answers (0)

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