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
015 package org.apache.tapestry5.corelib.components;
016
017 import org.apache.tapestry5.BindingConstants;
018 import org.apache.tapestry5.ClientElement;
019 import org.apache.tapestry5.ComponentResources;
020 import org.apache.tapestry5.MarkupWriter;
021 import org.apache.tapestry5.alerts.Alert;
022 import org.apache.tapestry5.alerts.AlertStorage;
023 import org.apache.tapestry5.annotations.*;
024 import org.apache.tapestry5.ioc.annotations.Inject;
025 import org.apache.tapestry5.json.JSONObject;
026 import org.apache.tapestry5.services.javascript.InitializationPriority;
027 import 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
038 public 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 }