CODEWITHSUNDEEP
jsfprimefacesjsf-2.2
Tiny
Tiny

Reputation: 27899

How to notify changes to a row of p:dataTable which is currently being edited to a corresponding backing bean?

How to know if contents of any column/s of the row being edited in a <p:dataTable> is changed? Given a simple example as follows.

The data table : 

<p:dataTable var="brand" value="#{testManagedBean}"
             lazy="true" editable="true" rows="10">

    <p:column headerText="Id">
        <h:outputText value="#{brand.brandId}"/>
    </p:column>

    <p:column headerText="Brand">
        <p:cellEditor>
            <f:facet name="output">
                <h:outputText value="#{brand.brandName}"/>
            </f:facet>
            <f:facet name="input">
                <p:inputText value="#{brand.brandName}"/>
            </f:facet>
        </p:cellEditor>
    </p:column>

    <p:column headerText="Edit" width="50">
        <p:rowEditor/>
    </p:column>
    <p:ajax event="rowEdit" listener="#{testManagedBean.onRowEdit}"/>
</p:dataTable>

The managed bean :

@ManagedBean
@ViewScoped
public final class TestManagedBean extends LazyDataModel<Brand> implements Serializable
{
    @EJB
    private final TestBeanLocal service=null;
    private static final long serialVersionUID = 1L;

    @Override
    public List<Brand> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String, Object> filters) {
        setRowCount(3);  //Just an example. Actually fetched from the database.
        return service.getList(first, pageSize, sortField, sortOrder, filters);
    }

    public void onRowEdit(RowEditEvent event) {
        //Do something to check if the row currently being edited has been changed.
        //If something is changed then, invoke an EJB method to propagate changes to the database.
        //If nothing is changed then, get rid of invoking an expensive business service method to unnecessarily execute an update query.

        System.out.println("onRowEdit() called.");
    }
}

Is there a way to invoke business service (to update database contents) if and only if the row currently being edited in the given <p:dataTable> is actually changed?

There could be more columns in <p:dataTable> as and when required as obvious.

Upvotes: 2

Views: 1885

Answers (1)

perissf
perissf

Reputation: 16273

Add this property to the bean:

private Brand original;

In the dataTable, add a listener for a rowEditInit event:

<p:ajax event="rowEditInit" listener="#{testManagedBean.onRowEditInit()}" />

Set the property value when the rowEditInit event is triggered:

public void onRowEditInit(RowEditEvent event) {
    original = (Brand) event.getObject();
}

Finally, do the checks in onRowEdit():

public void onRowEdit(RowEditEvent event) {
    Brand modified = (Brand) event.getObject();
    // compare modified against original
}

Upvotes: 1

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