001// Copyright 2011, 2012 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.corelib.components;
016
017import org.apache.tapestry5.BindingConstants;
018import org.apache.tapestry5.ClientElement;
019import org.apache.tapestry5.ComponentResources;
020import org.apache.tapestry5.MarkupWriter;
021import org.apache.tapestry5.alerts.Alert;
022import org.apache.tapestry5.alerts.AlertStorage;
023import org.apache.tapestry5.annotations.*;
024import org.apache.tapestry5.ioc.annotations.Inject;
025import org.apache.tapestry5.json.JSONObject;
026import org.apache.tapestry5.services.javascript.InitializationPriority;
027import org.apache.tapestry5.services.javascript.JavaScriptSupport;
028
029/**
030 * Renders out an empty {@code <div>} element and provides JavaScript initialization to make the element
031 * the container for alerts. After rendering markup (and initialization JavaScript), it
032 * {@linkplain org.apache.tapestry5.alerts.AlertStorage#dismissNonPersistent() removes all non-persistent alerts}.
033 *
034 * @tapestrydoc
035 * @since 5.3
036 */
037@SupportsInformalParameters
038public class Alerts implements ClientElement
039{
040
041    @Parameter(value="message:dismiss-label", defaultPrefix=BindingConstants.LITERAL)
042    private String dismissText;
043
044    @Inject
045    private ComponentResources resources;
046
047    @Environmental
048    private JavaScriptSupport javaScriptSupport;
049
050    @SessionState(create = false)
051    private AlertStorage storage;
052
053    private String clientId;
054
055    public String getClientId()
056    {
057        return clientId;
058    }
059
060    boolean beginRender(MarkupWriter writer)
061    {
062        clientId = javaScriptSupport.allocateClientId(resources);
063
064        writer.element("div", "id", clientId);
065        resources.renderInformalParameters(writer);
066        writer.end();
067
068        JSONObject spec = new JSONObject("id", clientId,
069                "dismissURL", resources.createEventLink("dismiss").toURI(),
070                "dismissText", dismissText);
071
072        javaScriptSupport.addInitializerCall(InitializationPriority.EARLY, "alertManager", spec);
073
074        if (storage != null)
075        {
076            addAlertsFromStorage();
077        }
078
079
080        return false;
081    }
082
083    Object onDismiss(@RequestParameter(value = "id", allowBlank = true) Long alertId)
084    {
085        // If the alert was created inside an Ajax request and AlertStorage did not previously
086        // exist, it can be null when the dismiss event comes up from the client.
087        if (storage != null)
088        {
089            if (alertId != null)
090            {
091                storage.dismiss(alertId);
092            } else
093            {
094                storage.dismissAll();
095            }
096        }
097
098        return new JSONObject();
099    }
100
101    @HeartbeatDeferred
102    void addAlertsFromStorage()
103    {
104        for (Alert alert : storage.getAlerts())
105        {
106            javaScriptSupport.addInitializerCall("addAlert", alert.toJSON());
107        }
108
109        storage.dismissNonPersistent();
110    }
111}