api/src/main/java/javax/faces/render/ResponseStateManager.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 javax.faces.render;

import javax.faces.application.StateManager;
import javax.faces.application.StateManager.SerializedView;
import javax.faces.context.FacesContext;
import java.io.IOException;

/**
 * see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>
 *
 * @author Manfred Geiler (latest modification by $Author$)
 * @author Stan Silvert
 * @version $Revision$ $Date$
 */
public abstract class ResponseStateManager
{
    public static final String RENDER_KIT_ID_PARAM = "javax.faces.RenderKitId";
    public static final String VIEW_STATE_PARAM = "javax.faces.ViewState";
    
    public void writeState(FacesContext context, Object state) throws IOException{
        SerializedView view;
        if (state instanceof SerializedView)
        {
            view = (SerializedView) state;
        }
        else
            if (state instanceof Object[])
            {
                Object[] structureAndState = (Object[]) state;

                if (structureAndState.length == 2)
                {
                    Object structureObj = structureAndState[0];
                    Object stateObj = structureAndState[1];

                    StateManager stateManager = context.getApplication().getStateManager();
                    view = stateManager.new SerializedView(structureObj, stateObj);
                }
                else
                {
                    throw new IOException("The state should be an array of Object[] of lenght 2");
                }
            }
        else
            {
                throw new IOException("The state should be an array of Object[] of lenght 2, or a SerializedView instance");
            }

        writeState(context, view);
    }
    
    /**
     * @deprecated
     */
    public void writeState(FacesContext context,
                           StateManager.SerializedView state)
            throws IOException {
        // does nothing as per JSF 1.2 javadoc
    }

    /**
     * @since 1.2
     */
    public Object getState(FacesContext context, String viewId) {
        Object[] structureAndState = new Object[2];
        structureAndState[0] = getTreeStructureToRestore(context, viewId);
        structureAndState[1] = getComponentStateToRestore(context);
        return structureAndState;
    }
    
    
    /**
     * @deprecated
     */
    public Object getTreeStructureToRestore(FacesContext context,
                                             String viewId) {
        return null;
    }
    

    /**
     * @deprecated
     */
    public Object getComponentStateToRestore(FacesContext context) {
        return null;
    }
    
    /**
     * Checks if the current request is a postback
     * @since 1.2
     */
    public boolean isPostback(FacesContext context) {
      return context.getExternalContext().
        getRequestParameterMap().containsKey(
              ResponseStateManager.VIEW_STATE_PARAM);
    }

}