How to write a custom converter for

Question

How can I write a custom converter when working with PrimeFaces components that use a list of POJO? My particular problem is with

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Answer 1

This problem is not primefaces related, just general JSF related.

Why should you hit the database again? Your bean already contains the list of Objects you want to display in a component, or is it request scoped?

• Create a Superclass for your Hibernate Pojo's containing an id field. If you don't want to create a super class just use the pojo class, but you need more converter classes.
• With that Superclass you can create a generic converter for all Pojo Classes containing a list of Pojo's passed in the constructor.
• Add the converter as a property in your session bean and use that converter in your JSF component.

If you access the final list via a get property in your bean or the nested one in the converter is of your choice.

public class SuperPojo
{
    protected Integer id;
    //constructor & getter
}

public class PojoTest extends SuperPojo 
{
    private String label = null;    
    //constructor & getter
}

public class SuperPojoConverter implements Converter
{
    private Collection superPojos;

    public IdEntityConverter(Collection superPojos)
    {
        this.superPojos = superPojos;
    }

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String value)
    {
        //catch exceptions and empty or  null value!
        final int intValue = Integer.parseInt(value);
        for(SuperPojo superPojo : this.superPojos)
            if(superPojo.getId().intValue() == intValue)
                return superPojo;

        return null;
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object value)
    {
        //catch null and instanceof
        return String.valueOf(((SuperPojo)value).getId().intValue());
    }

    public Collection getSuperPojos()
    {
        return this.superPojos;
    }
}

public class Bean 
{
    private SuperPojoConverter pojoTestConverter = null;

    public Bean()
    {
        final List pojoTests = //get list from hibernate
        this.pojoTestConverter = new SuperPojoConverter(pojoTests);
    }

    public SuperPojoConverter getPojoTestConverter()
    {
        return this.pojoTestConverter;
    }
}