/*
 * Copyright 2000-2016 Vaadin Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.vaadin.shared.communication;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import com.vaadin.shared.Connector;
import com.vaadin.shared.annotations.NoLayout;

/**
 * Interface to be implemented by all shared state classes used to communicate
 * basic information about a {@link Connector} from server to client.
 *
 * Shared state classes have to be declared in shared package to be accessible
 * both for server and client code.
 *
 * Shared state objects are only sent from the server to the client, and any
 * modifications from the client should be performed via an RPC call that
 * modifies the authoritative state on the server.
 *
 * A shared state class should be a bean with getters and setters for each
 * field. Supported data types are simple Java types, other beans and maps and
 * arrays of these.
 *
 * On the client side the connector should override
 * {@link com.vaadin.client.ui.AbstractConnector#getState()} to return the
 * correct state type. This automatically causes a correct state object to be
 * created.
 *
 * Subclasses of a {@link Connector} using shared state should also provide a
 * subclass of the shared state class of the parent class to extend the state. A
 * single {@link Connector} can only have one shared state object.
 *
 * @since 7.0
 */
public class SharedState implements Serializable {

    /**
     * The automatically managed resources used by the connector.
     *
     * @see com.vaadin.server.AbstractClientConnector#setResource(String,
     *      com.vaadin.server.Resource)
     * @see com.vaadin.client.ui.AbstractConnector#getResourceUrl(String)
     */
    public Map<String, URLReference> resources = new HashMap<>();

    public boolean enabled = true;
    /**
     * A set of event identifiers with registered listeners.
     */
    @NoLayout
    public Set<String> registeredEventListeners = null;

}