Apache Struts 2 Documentation > Home > Guides > Tag Developers Guide > Struts Tags > UI Tags > Themes and Templates > xhtml theme
Added by Patrick Lightbody, last edited by Ted Husted on Sep 03, 2006  (view change)

The xhtml provides all the basics that the simple theme provides and adds several features.

Wrapping the Simple Theme

The xhtml theme uses the "wrapping" technique described by Extending Themes. Let's look at how the HTML tags are wrapped by a standard header and footer. For example, in the text.ftl template, the controlheader.ftl and controlfooter.ftl templates are wrapped around the simple template.

<#--
/*
 * $Id$
 *
 * 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.
 */
-->
<#include "/${parameters.templateDir}/${parameters.theme}/controlheader.ftl" />
<#include "/${parameters.templateDir}/simple/text.ftl" />
<#include "/${parameters.templateDir}/xhtml/controlfooter.ftl" />

The controlheader.ftl is referenced using ${parameters.theme} so that the code can be reused by the ajax theme.

XHTML Theme Header

Now let's look at the controlheader.ftl and controlheader-core.ftl. Again, these are split up for easy re-use with the ajax theme) contents:

<#--
/*
 * $Id$
 *
 * 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.
 */
-->
<#include "/${parameters.templateDir}/xhtml/controlheader-core.ftl" />
    <td
<#if parameters.align?exists>
    align="${parameters.align?html}"<#t/>
</#if>
><#t/>
<#--
/*
 * $Id$
 *
 * 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.
 */
-->
<#--
	Only show message if errors are available.
	This will be done if ActionSupport is used.
-->
<#assign hasFieldErrors = parameters.name?exists && fieldErrors?exists && fieldErrors[parameters.name]?exists/>
<#if hasFieldErrors>
<#list fieldErrors[parameters.name] as error>
<tr errorFor="${parameters.id}">
<#if parameters.labelposition?default("") == 'top'>
    <td align="left" valign="top" colspan="2"><#rt/>
<#else>
    <td align="center" valign="top" colspan="2"><#rt/>
</#if>
        <span class="errorMessage">${error?html}</span><#t/>
    </td><#lt/>
</tr>
</#list>
</#if>
<#--
	if the label position is top,
	then give the label it's own row in the table
-->
<tr>
<#if parameters.labelposition?default("") == 'top'>
    <td align="left" valign="top" colspan="2"><#rt/>
<#else>
    <td class="tdLabel"><#rt/>
</#if>
<#if parameters.label?exists>
    <label <#t/>
<#if parameters.id?exists>
        for="${parameters.id?html}" <#t/>
</#if>
<#if hasFieldErrors>
        class="errorLabel"<#t/>
<#else>
        class="label"<#t/>
</#if>
    ><#t/>
<#if parameters.required?default(false) && parameters.requiredposition?default("right") != 'right'>
        <span class="required">*</span><#t/>
</#if>
${parameters.label?html}<#t/>
<#if parameters.required?default(false) && parameters.requiredposition?default("right") == 'right'>
 <span class="required">*</span><#t/>
</#if>
${parameters.labelseparator?default(":")?html}<#t/>
<#include "/${parameters.templateDir}/xhtml/tooltip.ftl" /> 
</label><#t/>
</#if>
    </td><#lt/>
<#-- add the extra row -->
<#if parameters.labelposition?default("") == 'top'>
</tr>
<tr>
</#if>

The header used by the HTML tags in the xhtml theme is complicated. However, a close look reveals that the logic produces two behaviors: either a two-column format or a two-row format. Generally the two-column approach is what we want, so that is the default option. To use the two-row approach, change the labelposition parameter to top.

Moving fieldErrors

The fieldErrors, usually caused by Validation, are printed out as a row above the HTML form element. Some people prefer that the errors display elsewhere, such as in a third column. If you wish to place these elsehwere, overriding the headers is easy, allowing you to continue to use the other features provided by this theme. See Template Loading for more information on how to do this.

XHTML Theme Footer

The primary objective of controlfooter.ftl is to close the table. But, before the table closes, the template checks for an after parameter.

<#--
/*
 * $Id$
 *
 * 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.
 */
-->
${parameters.after?if_exists}<#t/>
    </td><#lt/>
</tr>

While "after" isn't an attribute supported by any of the Struts Tags, if you are using FreeMarker Tags, Velocity Tags, or the param tag in any template language, you can add an after parameter to place any content you like after the simple theme template renders. The after attribute makes it easier to fine-tune HTML forms for your specific environment.

Special Interest

Two xhtml templates of special interest are head and form.

head template

The xhtml head template extends the simple head template and provides an additional CSS that helps render the WW:xhtml theme form elements.

<#--
/*
 * $Id$
 *
 * 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.
 */
-->
<link rel="stylesheet" href="<@s.url value='/struts/xhtml/styles.css' includeParams='none' encode='false' />" type="text/css"/>
<#include "/${parameters.templateDir}/simple/head.ftl" />

The head template imports a style sheet.

/*
 * $Id$
 *
 * 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.
 */

.wwFormTable {}
.label {font-style:italic; }
.errorLabel {font-style:italic; color:red; }
.errorMessage {font-weight:bold; text-align: center; color:red; }
.checkboxLabel {}
.checkboxErrorLabel {color:red; }
.required {color:red;}
.tdLabel {text-align:right; vertical-align:top; }

form template

The xhtml form template sets up the wrapping table around all the other WW:xhtml theme form elements. In addition to creating this wrapping table, the opening and closing templates also, if the validate parameter is set to true, enable Pure JavaScript Client Side Validation.

<#--
/*
 * $Id$
 *
 * 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.
 */
-->
<#include "/${parameters.templateDir}/xhtml/form-validate.ftl" />
<#include "/${parameters.templateDir}/simple/form.ftl" />
<#include "/${parameters.templateDir}/xhtml/control.ftl" />

The closing template, form-close.ftl*:

<#--
/*
 * $Id$
 *
 * 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.
 */
-->
<#include "/${parameters.templateDir}/xhtml/control-close.ftl" />
<#include "/${parameters.templateDir}/simple/form-close.ftl" />
<#include "/${parameters.templateDir}/xhtml/form-close-validate.ftl" />
<#if parameters.focusElement?if_exists != "">
<script type="text/javascript">
    StrutsUtils.addOnLoad(function() {
        var element = document.getElementById("${parameters.focusElement?html}");
        if(element) {
            element.focus();
        }
    });
</script>
</#if>