I'm trying to build a module for managing my database's catalogues like: country, enterprises, users etc. The user is supposed to select the catalog from a combobox and the system is supposed to display a table with the principal columns (not null in the database and some predefined by me). From the 3 objectives I have only achieved 2:
1.- get the @NotNull
fields from the Entity Classes after selecting the catalogue using reflection
2.-display the table with dynamic columns retrieving them from the above also.
But number 3 is giving me trouble. The thing is, I used this folling code in the view for displaying columns dynamically (based on the @NotNull
fields I stored in an object) ,(https://www.primefaces.org/showcase/ui/data/datatable/columns.xhtml):
<p:dataTable id="conceptos" var="pojo" value="#{catalogoMB.comocombo}>
<p:columns value="#{catalogoMB.columns}" var="column"
columnIndexVar="colIndex" sortBy="#{pojo[column.property]}" filterBy="#
{pojo[column.property]}">
<f:facet name="header">
<h:outputText value="#{column.header}" />
</f:facet>
<h:outputText value="#{pojo[column.property]}" />
</p:columns>
</p:dataTable>
So for example, in a normal way, without reflection the code above will work like this:
comocombo will have this properties: name, value, id; and my array of columns will be the same: name, value, id...
The thing is, comocombo
is a List<Object>
object where I store field's reflection class values, which returns java.lang.class instead of the instance of the EntityClass although I managed to invoke setter and getter from an Object instance of that class (combito) -supposedly-
so when I try to display pojo[column.property]
-> comocombo["id"], comocombo["name"] or comocombo["value"] it sends me an exception saying that java.lang.class
doesn't have this any properties....How can I reach them? I've read about Map<String, String>
and of .cast()
But I'm not sure this could be the way.
public void populateT(){
comocombo=new ArrayList<>();
Object tt ;
y = tabla.get(tabla.size()-1).getConcpetos(); //result of query type:
FindAll from the entity Class
try{
Class combito= Class.forName("sipe.services."+ catName); //the "path" of the
Entity Classes
for (Integer j=0; j<y.size()-1; j++){
tt=y.get(j);
for (Integer i=0; i< tabla.size()-1; i++){
tucampo=minustomayus(y.get(j).getClass().getDeclaredField(tabla.get(i).getNombre_c()).getName()); //tabla.get(i).getNombre_c()-> here I've stored the @NotNull properties' names (countryid, countryname...) whic are the same in columns = new ArrayList<ColumnModel>(); (catalogoMB.columns in the view)
Class cls= Class.forName("sipe.services."+ catName);
Method method = cls.getDeclaredMethod("get"+tucampo); // for example "countryid" -> getCountryid
Class<?> type = null;
for (Method methods : combito.getDeclaredMethods())
{ //Here I'm trying to invoke setter of the Entity Class in order to store its values..
//equivalent to: if o is an instance of Entity Class Country: Country o = new Country(); o.setCountryid(2);
if (methods.getName().contains("set"+tucampo)){
type=method.getReturnType();
methods.invoke(combito.newInstance(),method.invoke(tt));
}
}
I got mine to work this way, hope it helps
private void createDynamicColumns(){
//split column templates
String[] columnKeys = columnTemplate.split(" ");
//set first list to null
//this should be a List with no type specified
//eg List objects = new ArrayList<>();
//since you will dynamically populate it based on what the user selects from combobox
objects = null;
//clear columns
columns.clear();
//create a class from combobox selection
Class<?> forName = Class.forName("pathToClass." + comboboxSelection);
//get declared fields in that class
List<Field> asList = Arrays.asList(forName.getDeclaredFields());
//for each columkeys
//if method.getName() can be found in columnKeys
//add that columnKey to the new columnList;
for(int i =0;i< asList.size();i++)
for (String columnKey : columnKeys) {
String fieldName = asList.get(i).getName();
if (columnKey.equalsIgnoreCase(fieldName)) {
columns.add(fieldName);
}
}
//fetch from the database the objects list
objects = DAO.findAll();
}
and facelets page
<p:dataTable var="object" value="#{backingBean.objects}">
<p:columns value="#{BackingBean.columns}" var="column">
<f:facet name="header">
<h:outputText value="#{column}" />
</f:facet>
<h:outputText value="#{object[column]}" />
</p:columns>
</p:dataTable>
Remember to deal with exceptions