CODEWITHSUNDEEP
jsf-2java-ee-6myfacescomposite-componentuicomponents
maxtorzito
maxtorzito

Reputation: 318

What is the difference between put and add method in statehelper in JSF 2

What is the difference between:

methods in StateHelper in JSF?

Upvotes: 1

Views: 6818

Answers (2)

Robert Kühne
Robert Kühne

Reputation: 908

I found the api documentation not that helpful myself and investigated it. Each time add is called it appends another value to a list which is saved under the given key. If you call a get on that key you get back a list. The add method saves you creating that list and watches for corner cases, ex. creating the list when the key is empty.

The put you mentioned works similar to a map-like put. It saves a value under a key.

In contrast, there is an overloaded put with 3 parameters. It creates a map under that key and does a put on that map with another pair of key/value. Again, a get on the key gives you a map.

Thats basically how add and put work. There is some more going on to make partial states working. To sum it up: when you want to add several values under a key you can use add. put with 2 parameters gives you map-like behavior. put with 3 parameters allows you to fill a map under a key.

Upvotes: 2

Matt Handy
Matt Handy

Reputation: 30025

From the Mojarra API documentation:

void add(java.io.Serializable key, java.lang.Object value)
Store the specified value in a List that is internal to the StateHelper.

java.lang.Object put(java.io.Serializable key, java.lang.Object value) Return the previously stored value and store the specified key/value pair.

I guess MyFaces implemented it in a similar way.

Upvotes: 0

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