// This Source Code is in the Public Domain per: http://litesoft.org/License.txt
package org.litesoft.core;

import java.io.*;
import java.util.*;

import org.litesoft.core.typeutils.*;

@SuppressWarnings({"UnusedDeclaration"})
public abstract class ServerSession
{
    /**
     * Returns the object bound with the specified pClass Name in this ServerSession, or
     * <code>null</code> if no object is bound under the pClass Name.
     *
     * @param pClass specifying the Class Name of the object
     *
     * @return the object bound with the specified Class Name
     *
     * @throws IllegalArgumentException if pClass is null
     * @throws IllegalStateException    if this method is called on an
     *                                  expired ServerSession
     */
    @SuppressWarnings({"unchecked"})
    public <T extends Serializable> T getAttribute( Class<T> pClass )
    {
        return (T) LLgetAttribute( toName( pClass ) );
    }

    /**
     * Returns the object bound with the specified Class Name in this ServerSession, or
     * <code>null</code> if no object is bound under the Class Name.
     *
     * @param pClass specifying the Class Name of the object
     *
     * @return the object bound with the specified Class Name
     *
     * @throws IllegalArgumentException if pClass is null
     * @throws NoSuchElementException   if there is no object bound to the specified Class Name
     * @throws IllegalStateException    if this method is called on an
     *                                  expired ServerSession
     */
    public <T extends Serializable> T getRequired( Class<T> pClass )
            throws NoSuchElementException
    {
        T zInstance = getAttribute( pClass );
        if ( zInstance == null )
        {
            throw new NoSuchElementException();
        }
        return zInstance;
    }

    /**
     * Binds an object to this ServerSession, using the pClass Name specified.
     * If an object of the same pClass Name is already bound to this ServerSession,
     * the object is replaced.
     * <p/>
     * <p>If the value passed in is null, this has the same effect as calling
     * <code>removeAttribute()<code>.
     *
     * @param pClass    the Class Name to which the object will be bound;
     *                  cannot be null
     * @param pInstance the object to be bound
     *
     * @throws IllegalArgumentException if pClass is null
     * @throws IllegalStateException    if this method is called on an
     *                                  expired ServerSession
     */
    public <T extends Serializable, V extends T> void setAttribute( Class<T> pClass, V pInstance )
    {
        if ( pInstance == null )
        {
            LLremoveAttribute( toName( pClass ) );
        }
        else
        {
            LLsetAttribute( toName( pClass ), pInstance );
        }
    }

    /**
     * Removes the object bound with the specified pClass Name from
     * this ServerSession. If the ServerSession does not have an object
     * bound with the specified pClass Name, this method does nothing.
     *
     * @param pClass specifying the Class Name of the object
     *               to remove from this ServerSession
     *
     * @throws IllegalArgumentException if pClass is null
     * @throws IllegalStateException    if this method is called on an
     *                                  expired ServerSession
     */
    public <T extends Serializable> void removeAttribute( Class<T> pClass )
    {
        LLremoveAttribute( toName( pClass ) );
    }

    private String toName( Class<?> pClass )
    {
        Objects.assertNotNull( "Class", pClass );
        return pClass.getName();
    }

    abstract protected Serializable LLgetAttribute( String pName );

    abstract protected void LLsetAttribute( String pName, Serializable pInstance );

    abstract protected void LLremoveAttribute( String pName );
}