How to access Map key in jsf datatable

Question

I'm getting the error javax.el.PropertyNotFoundException: /member/apps/cms/edit.xhtml @228,49 value="#{props.key}": Property 'key' not found on type java.util.HashMap$Values when trying to display the datatable below.

<p:dataTable id="properties" var="props" value="#{contentEditorBacking.properties}" editable="true">

    <p:column headerText="Property">
        <p:cellEditor>
            <f:facet name="output"> 
                <h:outputText value="#{props.key}" />
            </f:facet>
            <f:facet name="input">
                <h:inputText value="#{props.key}" />
            </f:facet>
        </p:cellEditor>
    </p:column>
    <p:column headerText="Value">
        <p:cellEditor>
                        <f:facet name="output"> 
                <h:outputText value="#{props.value}" />
            </f:facet>
            <f:facet name="input">
                <h:inputText value="#{props.value}" />
            </f:facet>
        </p:cellEditor>
    </p:column>

    <p:column headerText="Edit">
        <p:rowEditor />
        <!-- Need to put an update on here yet -->
        <p:commandLink styleClass="ui-icon ui-icon-trash" id="deleteProperty" actionListener="#{contentEditorBacking.deleteProperty}">
                 <f:attribute name="key" value="#{props.key}" />
             </p:commandLink>
    </p:column>
</p:dataTable>

Here's the relevant part of my contentEditorBacking:

@ManagedBean
@ViewScoped
public class ContentEditorBacking {
    private Map<String, Properties> properties = new LinkedHashMap<String, Properties>();

    public Collection<Properties> getProperties() throws Exception{
        return properties.values();
    }

    public static class Properties{

        private String key;
        private String value;

        public Properties(String key, String value) {
            super();
            this.key = key;
            this.value = value;
        }

        public String getKey() {
            return key;
        }
        public void setKey(String key) {
            this.key = key;
        }
        public String getValue() {
            return value;
        }
        public void setValue(String value) {
            this.value = value;
        }
        @Override
        public String toString() {
            return "key=" + key + ", value=" + value + "";
        }

    }
}

How can i access the key value from my properties map?

Answer 1

Until the upcoming JSF 2.2, the <h:dataTable>/<p:dataTable> doesn't support Collection<E>. It only supports among others List<E>.

You need to replace

public Collection<Properties> getProperties() throws Exception{
    return properties.values();
}

by

private List<Properties> propertiesAsList;

public List<Properties> getProperties() throws Exception{
    return propertiesAsList;
}

and somewhere directly after map's initialization do this

propertiesAsList = new ArrayList<Properties>(properties.values());

(note: don't do it inside the getter!)

Answer 2

In the JSF code, you are trying to access the key property of the thing returned by getProperties() method, which is the entire collection. You need to iterate through the props variable.