001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.corelib.components;
014
015import org.apache.tapestry5.*;
016import org.apache.tapestry5.annotations.*;
017import org.apache.tapestry5.corelib.internal.ComponentActionSink;
018import org.apache.tapestry5.corelib.internal.FormSupportAdapter;
019import org.apache.tapestry5.corelib.internal.HiddenFieldPositioner;
020import org.apache.tapestry5.dom.Element;
021import org.apache.tapestry5.internal.services.RequestConstants;
022import org.apache.tapestry5.ioc.annotations.Inject;
023import org.apache.tapestry5.ioc.annotations.Symbol;
024import org.apache.tapestry5.json.JSONObject;
025import org.apache.tapestry5.services.*;
026import org.apache.tapestry5.services.compatibility.DeprecationWarning;
027import org.apache.tapestry5.services.javascript.JavaScriptSupport;
028import org.slf4j.Logger;
029
030/**
031 * A Zone is portion of the output page designed for easy dynamic updating via Ajax or other client-side effects. A
032 * Zone renders out as a <div> element (or whatever is specified in the template) and may have content initially,
033 * or may only get its content as a result of client side activity.
034 * <p/>
035 * When a user clicks an {@link org.apache.tapestry5.corelib.components.ActionLink} whose zone parameter is set triggers a
036 * series of client-side behaviors, and an Ajax request to the server.
037 * <p/>
038 * The server side event handler can return a {@link org.apache.tapestry5.Block} or a component to render as the new
039 * content on the client side. Often, re-rendering the Zone's {@linkplain #getBody() body} is useful. Multiple
040 * client-side zones may be updated via the {@link org.apache.tapestry5.services.ajax.AjaxResponseRenderer} service.
041 * <p/>
042 * You will often want to specify the id parameter of the Zone, in addition to its Tapestry component id; this "locks
043 * down" the client-side id, so the same value is used even in later partial renders of the page (essential if the Zone
044 * is nested inside another Zone). When you specify the client-side id, it is used exactly as provided (meaning that you
045 * are responsible for ensuring that there will not be an id conflict even in the face of multiple partial renders of
046 * the page). Failure to provide an explicit id results in a new, and non-predictable, id being generated for each
047 * partial render, which will often result in client-side failures to locate the element to update when the Zone is
048 * triggered.
049 * <p/>
050 * In some cases, you may want to know (on the server side) the client id of the zone that was updated; this is passed
051 * as part of the Ajax request, as the {@link QueryParameterConstants#ZONE_ID} parameter. An example use of this would
052 * be to provide new content into a Zone that updates the same Zone, when the Zone's client-side id is dynamically
053 * allocated (rather than statically defined). In most cases, however, the programmer is responsible for assigning a
054 * specific client-side id, via the id parameter.
055 * <p/>
056 * A Zone starts and stops a {@link Heartbeat} when it renders (both normally, and when re-rendering).
057 * <p/>
058 * After the client-side content is updated, a client-side event is fired on the zone's element. The constant
059 * <code>core/events:zone.didUpdate</code> can be used to listen to the event.
060 *
061 * @tapestrydoc
062 * @see AjaxFormLoop
063 * @see FormFragment
064 */
065@SupportsInformalParameters
066@Import(module = "t5/core/zone")
067public class Zone implements ClientBodyElement
068{
069    /**
070     * Name of a function on the client-side Tapestry.ElementEffect object that is invoked to make the Zone's
071     * &lt;div&gt; visible before being updated. If not specified, then the basic "show" method is used.
072     *
073     * @deprecated In 5.4, with no specific replacement, now does nothing (see notes on client-side JavaScript events, elsewhere)
074     */
075    @Parameter(defaultPrefix = BindingConstants.LITERAL)
076    private String show;
077
078    /**
079     * Name of a function on the client-side Tapestry.ElementEffect object that is invoked after the Zone's content has
080     * been updated. If not specified, then the basic "highlight" method is used, which performs a classic "yellow fade"
081     * to indicate to the user that and update has taken place.
082     *
083     * @deprecated In 5.4, with no specific replacement, now does nothing (see notes on client-side JavaScript events, elsewhere)
084     */
085    @Parameter(defaultPrefix = BindingConstants.LITERAL)
086    private String update;
087
088    /**
089     * The element name to render for the zone; this defaults to the element actually used in the template, or "div" if
090     * no specific element was specified.
091     */
092    @Parameter(required = true, allowNull = false, defaultPrefix = BindingConstants.LITERAL)
093    private String elementName;
094
095    /**
096     * If bound, then the id attribute of the rendered element will be this exact value. If not bound, then a unique id
097     * is generated for the element.
098     */
099    @Parameter(name = "id", defaultPrefix = BindingConstants.LITERAL)
100    private String idParameter;
101
102    @Environmental
103    private JavaScriptSupport javascriptSupport;
104
105    @Inject
106    private Environment environment;
107
108    /**
109     * In prior releases, this parameter could be overridden to false to force the outer element of the rendered
110     * Zone to be non-visible. This behavior is no longer supported.
111     *
112     * @deprecated Deprecated in 5.4 with no replacement.
113     */
114    @Parameter
115    private boolean visible;
116
117    /**
118     * if set to true, then Ajax updates related to this Zone will, when rending, use simple IDs (not namespaced ids).
119     * This is useful when the Zone contains a simple Form, as it (hopefully) ensures that the same ids used when
120     * initially rendering, and when processing the submission, are also used when re-rendering the Form (to present
121     * errors to the user).  The default is false, maintaining the same behavior as in Tapestry 5.3 and earlier.
122     *
123     * @since 5.4
124     */
125    @Parameter
126    private boolean simpleIds;
127
128    @Inject
129    private ComponentResources resources;
130
131    @Inject
132    private Heartbeat heartbeat;
133
134    @Inject
135    private Logger logger;
136
137    @Inject
138    private ClientDataEncoder clientDataEncoder;
139
140    @Inject
141    private HiddenFieldLocationRules rules;
142
143    private String clientId;
144
145    private boolean insideForm;
146
147    private HiddenFieldPositioner hiddenFieldPositioner;
148
149    private ComponentActionSink actionSink;
150
151    @Environmental(false)
152    private FormSupport formSupport;
153
154    @Inject
155    private DeprecationWarning deprecationWarning;
156
157    @Inject
158    @Symbol(SymbolConstants.COMPACT_JSON)
159    private boolean compactJSON;
160
161    String defaultElementName()
162    {
163        return resources.getElementName("div");
164    }
165
166    void pageLoaded()
167    {
168        deprecationWarning.ignoredComponentParameters(resources, "show", "update", "visible");
169    }
170
171    void beginRender(MarkupWriter writer)
172    {
173        clientId = resources.isBound("id") ? idParameter : javascriptSupport.allocateClientId(resources);
174
175        Element e = writer.element(elementName,
176                "id", clientId,
177                "data-container-type", "zone");
178
179        if (simpleIds)
180        {
181            e.attribute("data-simple-ids", "true");
182        }
183
184        resources.renderInformalParameters(writer);
185
186        insideForm = formSupport != null;
187
188        if (insideForm)
189        {
190            JSONObject parameters = new JSONObject(RequestConstants.FORM_CLIENTID_PARAMETER, formSupport.getClientId(),
191                    RequestConstants.FORM_COMPONENTID_PARAMETER, formSupport.getFormComponentId());
192
193            e.attribute("data-zone-parameters",
194                    parameters.toString(compactJSON));
195
196            hiddenFieldPositioner = new HiddenFieldPositioner(writer, rules);
197
198            actionSink = new ComponentActionSink(logger, clientDataEncoder);
199
200            environment.push(FormSupport.class, new FormSupportAdapter(formSupport)
201            {
202                @Override
203                public <T> void store(T component, ComponentAction<T> action)
204                {
205                    actionSink.store(component, action);
206                }
207
208                @Override
209                public <T> void storeCancel(T component, ComponentAction<T> action)
210                {
211                    actionSink.storeCancel(component, action);
212                }
213
214                @Override
215                public <T> void storeAndExecute(T component, ComponentAction<T> action)
216                {
217                    store(component, action);
218
219                    action.execute(component);
220                }
221
222            });
223        }
224
225        heartbeat.begin();
226    }
227
228    void afterRender(MarkupWriter writer)
229    {
230        heartbeat.end();
231
232        if (insideForm)
233        {
234            environment.pop(FormSupport.class);
235
236            if (actionSink.isEmpty())
237            {
238                hiddenFieldPositioner.discard();
239            } else
240            {
241                hiddenFieldPositioner.getElement().attributes("type", "hidden",
242
243                        "name", Form.FORM_DATA,
244
245                        "value", actionSink.getClientData());
246            }
247        }
248
249        writer.end(); // div
250    }
251
252    /**
253     * The client id of the Zone; this is set when the Zone renders and will either be the value bound to the id
254     * parameter, or an allocated unique id. When the id parameter is bound, this value is always accurate.
255     * When the id parameter is not bound, the clientId is set during the {@linkplain BeginRender begin render phase}
256     * and will be null or inaccurate before then.
257     *
258     * @return client-side element id
259     */
260    public String getClientId()
261    {
262        if (resources.isBound("id"))
263            return idParameter;
264
265        // TAP4-2342. I know this won't work with a Zone with no given clientId and that was already 
266        // via AJAX inside an outer Zone, but it's still better than nothing.
267        if (clientId == null)
268        {
269            clientId = resources.getId();
270        }
271
272        return clientId;
273    }
274
275    /**
276     * Returns the zone's body (the content enclosed by its start and end tags). This is often used as part of an Ajax
277     * partial page render to update the client with a fresh render of the content inside the zone.
278     *
279     * @return the zone's body as a Block
280     */
281    public Block getBody()
282    {
283        return resources.getBody();
284    }
285}