/*
 * 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 org.apache.catalina;


import java.beans.PropertyChangeListener;
import java.io.IOException;


A Store is the abstraction of a Catalina component that provides
persistent storage and loading of Sessions and their associated user data.
Implementations are free to save and load the Sessions to any media they
wish, but it is assumed that saved Sessions are persistent across
server or context restarts.
Author:
Craig R. McClanahan/**
 * A <b>Store</b> is the abstraction of a Catalina component that provides
 * persistent storage and loading of Sessions and their associated user data.
 * Implementations are free to save and load the Sessions to any media they
 * wish, but it is assumed that saved Sessions are persistent across
 * server or context restarts.
 *
 * @author Craig R. McClanahan
 */
public interface Store {

    // ------------------------------------------------------------- Properties

    
Returns:
the Manager instance associated with this Store./**
     * @return the Manager instance associated with this Store.
     */
    public Manager getManager();


    
Set the Manager associated with this Store.
Params:
manager – The Manager which will use this Store./**
     * Set the Manager associated with this Store.
     *
     * @param manager The Manager which will use this Store.
     */
    public void setManager(Manager manager);


    
Throws:
IOException – if an input/output error occurs
Returns:
the number of Sessions present in this Store./**
     * @return the number of Sessions present in this Store.
     *
     * @exception IOException if an input/output error occurs
     */
    public int getSize() throws IOException;


    // --------------------------------------------------------- Public Methods


    
Add a property change listener to this component.
Params:
listener – The listener to add/**
     * Add a property change listener to this component.
     *
     * @param listener The listener to add
     */
    public void addPropertyChangeListener(PropertyChangeListener listener);


    
Throws:
IOException – if an input/output error occurred
Returns:
an array containing the session identifiers of all Sessions
currently saved in this Store.  If there are no such Sessions, a
zero-length array is returned./**
     * @return an array containing the session identifiers of all Sessions
     * currently saved in this Store.  If there are no such Sessions, a
     * zero-length array is returned.
     *
     * @exception IOException if an input/output error occurred
     */
    public String[] keys() throws IOException;


    
Load and return the Session associated with the specified session
identifier from this Store, without removing it.  If there is no
such stored Session, return null.
Params:
id – Session identifier of the session to load
Throws:
ClassNotFoundException – if a deserialization error occurs
IOException – if an input/output error occurs
Returns:
the loaded Session instance/**
     * Load and return the Session associated with the specified session
     * identifier from this Store, without removing it.  If there is no
     * such stored Session, return <code>null</code>.
     *
     * @param id Session identifier of the session to load
     *
     * @exception ClassNotFoundException if a deserialization error occurs
     * @exception IOException if an input/output error occurs
     * @return the loaded Session instance
     */
    public Session load(String id)
        throws ClassNotFoundException, IOException;


    
Remove the Session with the specified session identifier from
this Store, if present.  If no such Session is present, this method
takes no action.
Params:
id – Session identifier of the Session to be removed
Throws:
IOException – if an input/output error occurs/**
     * Remove the Session with the specified session identifier from
     * this Store, if present.  If no such Session is present, this method
     * takes no action.
     *
     * @param id Session identifier of the Session to be removed
     *
     * @exception IOException if an input/output error occurs
     */
    public void remove(String id) throws IOException;


    
Remove all Sessions from this Store.
Throws:
IOException – if an input/output error occurs/**
     * Remove all Sessions from this Store.
     *
     * @exception IOException if an input/output error occurs
     */
    public void clear() throws IOException;


    
Remove a property change listener from this component.
Params:
listener – The listener to remove/**
     * Remove a property change listener from this component.
     *
     * @param listener The listener to remove
     */
    public void removePropertyChangeListener(PropertyChangeListener listener);


    
Save the specified Session into this Store.  Any previously saved
information for the associated session identifier is replaced.
Params:
session – Session to be saved
Throws:
IOException – if an input/output error occurs/**
     * Save the specified Session into this Store.  Any previously saved
     * information for the associated session identifier is replaced.
     *
     * @param session Session to be saved
     *
     * @exception IOException if an input/output error occurs
     */
    public void save(Session session) throws IOException;


}