RE: Constructing Datatable with Columns Having Foreign Key references

[Romanowski, Tim]

Couple questions:

 

1) What is locale$select doing in  ="#{locale$select.selectStudent}"?  Is that assuming there is a properties file you're using for locale?  I'm familiar with useing "#{foo.bar}" and "${bar}", but the notation isn't familiar to me.

 

2) You call select.selectStudent and set a parameter "name" to the value of the current student, "#{s}" ... I understand that forcing an action will cause that portion of the table to be updated, but how do I place multiple 'sub-rows' in a row initially, without requiring a user to click on a particular row?  Does the immediate="true" attribute force the action to take place as the table is rendering?  If so, that is excellent, I didn't realize the immediate attribute would do that for an action (like a commandLink or commandButton). My goal is to populate this entire table on first loading, and not requiring a user to click on a particular row to see the many sub-rows in a column. 

 

TR

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From: Gary VanMatre [mailto:[EMAIL PROTECTED]
Sent: Wednesday, April 19, 2006 5:51 PM
To: MyFaces Discussion
Subject: RE: Constructing Datatable with Columns Having Foreign Key references

How about something like this:

 

JSP:

   <h:form id="test">
   <h:dataTable value="#{locale$select.classes}" var="class">
      <h:column>
          <f:facet name="header">
              <f:verbatim>Students</f:verbatim>  
          </f:facet>
          <h:dataTable value="#{class.students}" var="s">
              <h:column>
                  <h:commandLink action="" value="#{s}" immediate="true">
                &n bsp;&n bsp;   <f:param name="name" value="#{s}"/>
                  </h:commandLink>
              </h:column>
          </h:dataTable>     
      </h:column>
      <h:column>
          <f:facet name="header">
              <f:verbatim>Class Id</f:verbatim>  
          </f:facet>
          <h:outputText value="#{class.id}"/>
      </h:column>
      <h :column>
          <f:facet name="header">
              <f:verbatim>Description</f:verbatim>  
          </f:facet>
          <h:outputText value="#{class.description}"/>
      </h:column>

   </h:dataTable>
   </h:form>

Managed Bean:

    public ClassInfo[] getClasses() {
       ClassInfo[] classes = new ClassInfo[3];
       classes[0] = new ClassInfo(new Integer(100), "Basket Weaving");
       classes[1] = new ClassInfo(new Integer(200), "Industrial arts");
       classes[2] = new ClassInfo(new Integer(300), "Computer Science");
      
       return classes;
      
    }
   
   
    public String selectStudent() {
        FacesContext facesContext = FacesContext.getCurrentInstance();
        String name = (String) facesContext.getExternalContext().getRequestParameterMap().get("name");
   &nbs p;&nbs p;   System.out.println(name);
       
        return null;
    }

ClassInfo Class:

public class ClassInfo {
    private Integer id = null;
    private String description = null;
   
   
    public ClassInfo(Integer id, String description) {
       this.id = id;
       this.description = description;
    }
   
    public String getDescription() {
        return description;
    }
   
    public void setDescription(String description) {
        this.description = description;
    }
   
    public Integer getId() {
        return id;
    }
   
    public void setId(Integer id) {
        this.id = id;
    }
   
    
    public String[] getStudents() {
         //FacesContext facesContext = FacesContext.getCurrentInstance();
         // simulate a db call
         if (id.equals(100)) {
            return new String[] {
                "Bob", "Sally", "Fred"       
            };
         } else if (id.equals(200)) {
            return new String[] {"Joe", "Ben"};   
          } else
            return new String[] {"Gary", "Zane", "Seth"};
       
    }
   
   
}

Gary

 

-------------- Original message --------------
From: "Romanowski, Tim" <[EMAIL PROTECTED]>

Gary, thanks for the suggestion, but I'm not sure I understand how this will help me:

 

Are you suggesting to use the datalist within my datatable?  In such a case, the value returned by "#{countryList.countries}" is dependent upon the row id of my datatable.  So I would have several columns in my datatable, of which one of those columns can have multiple 'sub-rows' per datatable row.  When I render my datatable, how would I access the current row id in a bean so that I can do a calculation for displaying more data in _another_ column for the _same_ row?   Emphasis added since the wording can get tricky.

 

I could solve this by having two Lists, one which is used for the datatable, and another used by the particular column.  I could then synchronize those lists myself, and write some spaghetti to increment a counter every time I grab the data for the particular multi-row column.  However, that is a pretty ugly way of handling this, and I'm hoping there is an elegant (or at least less ugly) solution.  Thoughts? 

---

From: Gary VanMatre [mailto:[EMAIL PROTECTED]
Sent: Wednesday, April 19, 2006 4:16 PM
To: MyFaces Discussion
Subject: RE: Constructing Datatable with Columns Having Foreign Key references

 

You might give the dataList component a look.  The rowIndexVar will give you the current row (http://myfaces.apache.org/tomahawk/dataList.html).

 

    <t:dataList id="data1"
        styleClass="standardList"
        var="country"
        value="#{countryList.countries}"
        layout="simple"
        rowCountVar="rowCount"
        rowIndexVar="rowIndex">
        <h:outputText value="#{country.name}" />
        <h:outputText value=", " rendered="#{rowIndex + 1 < rowCount}" />
    </t:dataList>

 

Gary

-------------- Original message --------------
From: "Romanowski, Tim" <[EMAIL PROTECTED]>

Perhaps to point this in a useful direction: is it possible to get a value of the current row (such as "row.id") from the FacesContext in a bean?  For example:

 

<t:column>

  <f:facet name="header">

    <f:verbatim>MyValues</f:verbatim>

  </f:facet>

  <h:outputText value="${currentRow.currentRowValues}" />

</t:column>

 

Is it possible to access another value for the currentRow object, such as currentRow.ID, by calling the FacesContext in a backing bean? If so, what is the proper way to do this? 

 

 

 

---

From: Romanowski, Tim
Sent: Wednesday, April 19, 2006 9:57 AM
To: users@myfaces.apache.org
Subject: Constructing Datatable with Columns Having Foreign Key references

 

When constructing a myfaces (tomahawk) datatable, I have a couple columns that each contain foreign key references.  How do you guys handle the situation where a given row in a datable might have a column that itself has multiple rows?  In other words, row 1 of my datable has a column which itself contains several rows.  It doesn't seem like placing a child datatable within a parent datatable will necessarily solve anything, since I don't know what data goes in the current row until I know the value of a column in the current row. 

From reading looking through the archives and some other sites, it looks (is this true?) that there is no clean way to pass a parameter of the current row id back to a backing bean to do some processing for dynamically constructing the current row.    I've seen some suggestions on setting f:param and using that value, but setting an f:param to equal the current rowid in a datatable doesn't seem to work.  I've also seen another kludge that used a 'disabled' property to set a map value, but that was, well, a kludge (but perhaps the best way?). 

Again, how are you guys constructing complex tables?  Any help would be greatly appreciated!

_____________________________________

TR