ScriptSessions.java

/*
 * Copyright 2005 Joe Walker
 *
 * 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 org.directwebremoting;

import java.util.Collection;

import org.directwebremoting.event.ScriptSessionBindingListener;

/**
 * A class to act on the current {@link ScriptSession}(s).
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class ScriptSessions
{
    /**
     * Binds an object to this session, using the name specified.
     * If an object of the same name is already bound to the session, the
     * object is replaced.
     * <p>After this method executes, and if the new object implements
     * {@link ScriptSessionBindingListener}, the container calls
     * {@link ScriptSessionBindingListener#valueBound}.
     * <p>If an object was already bound to this session of this name that
     * implements {@link ScriptSessionBindingListener}, its
     * {@link ScriptSessionBindingListener#valueUnbound} method is called.
     * <p>If the value passed in is null, this has the same effect as calling
     * {@link #removeAttribute}.
     * @param name the name to which the object is bound; cannot be null
     * @param value the object to be bound
     * @throws IllegalStateException if the page has been invalidated
     */
    public static void setAttribute(final String name, final Object value)
    {
        Browser.withAllSessions(new Runnable()
        {
            public void run()
            {
                Collection<ScriptSession> sessions = Browser.getTargetSessions();
                for (ScriptSession scriptSession : sessions)
                {
                    scriptSession.setAttribute(name, value);
                }
            }
        });
    }

    /**
     * Removes the object bound with the specified name from this session.
     * If the session does not have an object bound with the specified name,
     * this method does nothing.
     * <p>After this method executes, and if the object implements
     * {@link ScriptSessionBindingListener}, the container calls
     * {@link ScriptSessionBindingListener#valueUnbound}.
     * @param name the name of the object to remove from this session
     * @throws IllegalStateException if the page has been invalidated
     */
    public static void removeAttribute(final String name)
    {
        Browser.withAllSessions(new Runnable()
        {
            public void run()
            {
                Collection<ScriptSession> sessions = Browser.getTargetSessions();
                for (ScriptSession scriptSession : sessions)
                {
                    scriptSession.removeAttribute(name);
                }
            }
        });
    }

    /**
     * Add a script to the list waiting for remote execution.
     * @param script The script to execute
     */
    public static void addScript(final ScriptBuffer script)
    {
        Browser.withAllSessions(new Runnable()
        {
            public void run()
            {
                Collection<ScriptSession> sessions = Browser.getTargetSessions();
                for (ScriptSession scriptSession : sessions)
                {
                    scriptSession.addScript(script);
                }
            }
        });
    }

    /**
     * Utility to add the given script to all known browsers.
     * This version automatically wraps the string in a ClientScript object.
     * @param scriptString The Javascript to send to the browsers
     */
    public static void addScript(String scriptString)
    {
        final ScriptBuffer script = new ScriptBuffer(scriptString);

        Browser.withAllSessions(new Runnable()
        {
            public void run()
            {
                Collection<ScriptSession> sessions = Browser.getTargetSessions();
                for (ScriptSession scriptSession : sessions)
                {
                    scriptSession.addScript(script);
                }
            }
        });
    }

    /**
     * Call a named function with one parameter.
     * @param funcName The name of the function to call
     * @param params The parameters to the above function
     */
    public static void addFunctionCall(String funcName, Object... params)
    {
        ScriptBuffer script = new ScriptBuffer();
        script.appendScript(funcName).appendScript("(");

        for (int i = 0; i < params.length; i++)
        {
            if (i != 0)
            {
                script.appendScript(",");
            }
            script.appendData(params[i]);
        }

        script.appendScript(");");
        addScript(script);
    }
}