org.directwebremoting.ScriptSessions Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code.
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/*
 * 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.
     * After this method executes, and if the new object implements
     * {@link ScriptSessionBindingListener}, the container calls
     * {@link ScriptSessionBindingListener#valueBound}.
     * 
If an object was already bound to this session of this name that
     * implements {@link ScriptSessionBindingListener}, its
     * {@link ScriptSessionBindingListener#valueUnbound} method is called.
     * 
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(String name, Object value)
    {
        Collection 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.
     * 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(String name)
    {
        Collection 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(ScriptBuffer script)
    {
        Collection 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)
    {
        addScript(new ScriptBuffer(scriptString));
    }

    /**
     * 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);
    }
}