org.apache.wicket.ajax.AjaxNewWindowNotifyingBehavior.java Source code

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Here is the source code for org.apache.wicket.ajax.AjaxNewWindowNotifyingBehavior.java

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/*
 * 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.wicket.ajax;

import java.util.UUID;

import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.ajax.attributes.AjaxCallListener;
import org.apache.wicket.ajax.attributes.AjaxRequestAttributes;
import org.apache.wicket.markup.head.IHeaderResponse;
import org.apache.wicket.markup.head.OnLoadHeaderItem;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.string.Strings;
import org.danekja.java.util.function.serializable.SerializableConsumer;

/**
 * An Ajax behavior that notifies when a new browser window/tab is opened with url to a page
 * instance which is already opened in another window/tab in the same user session.
 *
 * @since 6.0
 * @see #onNewWindow(AjaxRequestTarget)
 */
public class AjaxNewWindowNotifyingBehavior extends AbstractDefaultAjaxBehavior {
    private static final long serialVersionUID = 1L;

    /**
     * The name of the HTTP request parameter that transports the current page window's name.
     */
    private static final String PARAM_WINDOW_NAME = "windowName";

    /**
     * The name of the window the page is bound to.
     */
    private String boundName;

    /**
     * Returns the window's name.
     * 
     * @return name of {@value null} if not yet bound to a window
     */
    public String getWindowName() {
        return boundName;
    }

    /**
     * Overridden to add the current window name to the request.
     */
    @Override
    protected void updateAjaxAttributes(AjaxRequestAttributes attributes) {
        super.updateAjaxAttributes(attributes);

        String parameter = "return {'" + PARAM_WINDOW_NAME + "': window.name}";
        attributes.getDynamicExtraParameters().add(parameter);

        if (boundName != null) {
            // already bound, send request only when changed
            attributes.getAjaxCallListeners().add(new AjaxCallListener() {
                @Override
                public CharSequence getPrecondition(Component component) {
                    return String.format("return (window.name !== '%s');", boundName);
                }
            });
        }
    }

    /**
     * Overridden to initiate a request once the page was rendered.
     */
    @Override
    public void renderHead(Component component, IHeaderResponse response) {
        super.renderHead(component, response);

        response.render(
                OnLoadHeaderItem.forScript("setTimeout(function() {" + getCallbackScript().toString() + "}, 30);"));
    }

    @Override
    protected void respond(AjaxRequestTarget target) {
        String windowName = getComponent().getRequest().getRequestParameters().getParameterValue(PARAM_WINDOW_NAME)
                .toString();

        if (boundName == null) {
            // not bound to any window yet

            if (Strings.isEmpty(windowName)) {
                // create new name
                windowName = newWindowName();
                target.appendJavaScript(String.format("window.name = '%s';", windowName));
            }

            // now bound to window
            boundName = windowName;
        } else if (boundName.equals(windowName) == false) {
            onNewWindow(target);
        }
    }

    /**
     * Create a name for a nameless window, default uses a random {@link UUID}.
     * 
     * @return window name
     */
    protected String newWindowName() {
        return UUID.randomUUID().toString();
    }

    /**
     * A callback method when a new window/tab is opened for a page instance which is already opened
     * in another window/tab.
     * <p>
     * Default implementation redirects to a new page instance with identical page parameters.
     *
     * @param target
     *            the current request handler
     */
    protected void onNewWindow(AjaxRequestTarget target) {
        Page page = getComponent().getPage();

        getComponent().setResponsePage(page.getClass(), page.getPageParameters());
    }

    /**
     * Creates an {@link AjaxNewWindowNotifyingBehavior} based on lambda expressions
     * 
     * @param onNewWindow
     *            the {@code SerializableConsumer} which accepts the {@link AjaxRequestTarget}
     * @return the {@link AjaxNewWindowNotifyingBehavior}
     */
    public static AjaxNewWindowNotifyingBehavior onNewWindow(SerializableConsumer<AjaxRequestTarget> onNewWindow) {
        Args.notNull(onNewWindow, "onNewWindow");

        return new AjaxNewWindowNotifyingBehavior() {
            private static final long serialVersionUID = 1L;

            @Override
            protected void onNewWindow(AjaxRequestTarget target) {
                onNewWindow.accept(target);
            }
        };
    }
}