javax.faces.component.StateHelper Maven / Gradle / Ivy

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package javax.faces.component;

import java.io.Serializable;

/**
 * Define a Map-like contract
 * that makes it easier for components to implement {@link
 * PartialStateHolder}.  Each {@link UIComponent} in the view will
 * return an implementation of this interface from its {@link
 * UIComponent#getStateHelper} method.
 *
 * @since 2.0
 */
public interface StateHelper extends StateHolder {


    /**
     * Return the previously stored value
     * and store the specified key/value pair.  This is intended to
     * store data that would otherwise reside in an instance variable on
     * the component.

     * @since 2.0

     * @param key the key for the value
     * @param value the value
     */
    Object put(Serializable key, Object value);


    /**
     * Remove the key/value pair from the
     * helper, returning the value previously stored under this key.
     * @param key the key to remove
     * @since 2.0
     */
    Object remove(Serializable key);


    /**
     * Store the specified
     * mapKey/value in a Map that
     * is internal to the helper, and return the previously stored
     * value.  The Map will then be associated with
     * key.
     *
     * 

     * It's important to note for delta tracking that any
     * modifications to the internal Map be made through
     * this method or {@link StateHelper#remove(java.io.Serializable,
     * Object)}.
     *
     * 
     *
     * @since 2.0
     * @param key the key of the map itself
     * @param mapKey the key within the internal map
     * @param value the value for the key in the internal map
     */
    Object put(Serializable key, String mapKey, Object value);


    /**
     * Return the value currently
     * associated with the specified key if any.
     * @param key the key for which the value should be returned.
     * @since 2.0
     */
    Object get(Serializable key);


    /**
     * Attempts to find a value associated
     * with the specified key, using the value expression collection
     * from the component if no such value is found.
     * @param key the name of the value in the internal map, or the name
     * of a value expression in the components value expression
     * collection.
     *
     * @since 2.0
     */
    Object eval(Serializable key);


    /**
     * Performs the same logic as {@link
     * #eval(java.io.Serializable)} } but if no value is found, this
     * will return the specified defaultValue

     * @param key the key for which the value should be returned.
     * @param defaultValue the value to return if no value is found in
     * the call to eval().
     * @since 2.0
     */
    Object eval(Serializable key, Object defaultValue);


    /**
     * Store the specified
     * value in a List that is internal to the
     * StateHelper.
     *
     * It's important to note for delta
     * tracking that any modifications to the internal List
     * be made through this method or {@link
     * StateHelper#remove(java.io.Serializable, Object)}.
     *
     * @param key the key for which the value should be returned.
     * @param value the value to add
     * @since 2.0
     */
    void add(Serializable key, Object value);


    /**
     * Remove a value from the inner data
     * structure.  Look in the inner data structure for the value at the
     * given key.  If the value is a Map,
     * remove and return the value under the key given by the
     * valueOrKey argument.  If the value is a
     * Collection, simply remove the value given by
     * the argument valueOrKey and return null.
     *
     * @param key the key of in the inner data structure whose value is
     * a Collection or Map
     * @param valueOrKey the value or key to be removed.
     */
    Object remove(Serializable key, Object valueOrKey);


}