play.mvc

Interface QueryStringBindable<T extends QueryStringBindable<T>>

public interface QueryStringBindable<T extends QueryStringBindable<T>>

Binder for query string parameters.

Any type T that implements this class can be bound to/from query one or more query string parameters. The only requirement is that the class provides a noarg constructor.

For example, the following type could be used to encode pagination:

 class Pager implements QueryStringBindable<Pager> {
     public int index;
     public int size;

     public Optional<Pager> bind(String key, Map<String, String[]> data) {
         if (data.contains(key + ".index" && data.contains(key + ".size") {
             try {
                 index = Integer.parseInt(data.get(key + ".index")[0]);
                 size = Integer.parseInt(data.get(key + ".size")[0]);
                 return Optional.<Pager>ofNullable(this);
             } catch (NumberFormatException e) {
                 return Optional.<Pager>empty();
             }
         } else {
             return Optional.<Pager>empty();
         }
     }

     public String unbind(String key) {
         return key + ".index=" + index + "&" + key + ".size=" + size;
     }

     public String javascriptUnbind() {
         return "function(k,v) {\n" +
             "    return encodeURIComponent(k+'.index')+'='+v.index+'&'+encodeURIComponent(k+'.size')+'='+v.size;\n" +
             "}";
     }
 }
 

Then, to match the URL /foo?p.index=5&p.size=42, you could define the following route:

 GET  /foo     controllers.Application.foo(p: Pager)
 

Of course, you could ignore the p key specified in the routes file and just use hard coded index and size parameters if you pleased.

Method Summary

Modifier and Type	Method and Description
Optional<T>	bind(String key, Map<String,String[]> data) Bind a query string parameter.
String	javascriptUnbind() Javascript function to unbind in the Javascript router.
String	unbind(String key) Unbind a query string parameter.

Method Detail

bind

Optional<T> bind(String key,
                 Map<String,String[]> data)

Bind a query string parameter.

Parameters:

key - Parameter key

data - The query string data

Returns:

An instance of this class (it could be this class) if the query string data can be bound to this type, or None if it couldn't.

unbind

String unbind(String key)

Unbind a query string parameter. This should return a query string fragment, in the form key=value[&key2=value2...].

Parameters:

key - Parameter key

Returns:

this key's query-string fragment.

javascriptUnbind

String javascriptUnbind()

Javascript function to unbind in the Javascript router.

If this bindable just represents a single value, you may return null to let the default implementation handle it.

Returns:

null for default behavior, otherwise a valid javascript function that accepts the key and value as arguments and returns a valid query string fragment (in the format key=value)