org.apache.wicket.markup.head.CssHeaderItem Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of wicket-core Show documentation
Wicket is a Java web application framework that takes simplicity, separation of concerns and ease of development to a whole new level. Wicket pages can be mocked up, previewed and later revised using standard WYSIWYG HTML design tools. Dynamic content processing and form handling is all handled in Java code using a first-class component model backed by POJO data beans that can easily be persisted using your favorite technology.
There is a newer version: 10.0.0
Show newest version
/*
 * 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.markup.head;

import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.core.util.string.CssUtils;
import org.apache.wicket.request.Response;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.request.resource.ResourceReference;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.string.Strings;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Base class for all {@link HeaderItem}s that represent stylesheets. This class mainly contains
 * factory methods.
 * 
 * @author papegaaij
 */
public abstract class CssHeaderItem extends HeaderItem
{
	private static final Logger logger = LoggerFactory.getLogger(CssHeaderItem.class);

	/**
	 * The condition to use for Internet Explorer conditional comments. E.g. "IE 7".
	 * {@code null} or empty string for no condition.
	 *
	 * Warning: the conditional comments don't work when injected dynamically
	 * with JavaScript (i.e. in Ajax response). An alternative solution is to use user agent sniffing
	 * at the server side:
	 * 	 * public void renderHead(IHeaderResponse response) {
	 *   WebClientInfo clientInfo = (WebClientInfo) getSession().getClientInfo();
	 *   ClientProperties properties = clientInfo.getProperties();
	 *   if (properties.isBrowserInternetExplorer() && properties.getBrowserVersionMajor() >= 8) {
	 *     response.renderCSSReference(new PackageResourceReference(MyPage.class, "my-conditional.css" ));
	 *   }
	 * }
	 * 
	 */
	private final String condition;
	
	protected CssHeaderItem(String condition)
	{
		this.condition = condition;
	}

	/**
	 * @return the condition to use for Internet Explorer conditional comments. E.g. "IE 7".
	 */
	public String getCondition()
	{
		return condition;
	}
	
	/**
	 * Creates a {@link CssReferenceHeaderItem} for the given reference.
	 * 
	 * @param reference
	 *            a reference to a CSS resource
	 * @return A newly created {@link CssReferenceHeaderItem} for the given reference.
	 */
	public static CssReferenceHeaderItem forReference(ResourceReference reference)
	{
		return forReference(reference, null);
	}

	/**
	 * Creates a {@link CssReferenceHeaderItem} for the given reference.
	 * 
	 * @param reference
	 *            a reference to a CSS resource
	 * @param media
	 *            the media type for this CSS ("print", "screen", etc.)
	 * @return A newly created {@link CssReferenceHeaderItem} for the given reference.
	 */
	public static CssReferenceHeaderItem forReference(ResourceReference reference, String media)
	{
		return forReference(reference, null, media);
	}

	/**
	 * Creates a {@link CssReferenceHeaderItem} for the given reference.
	 * 
	 * @param reference
	 *            a reference to a CSS resource
	 * @param pageParameters
	 *            the parameters for this CSS resource reference
	 * @param media
	 *            the media type for this CSS ("print", "screen", etc.)
	 * @return A newly created {@link CssReferenceHeaderItem} for the given reference.
	 */
	public static CssReferenceHeaderItem forReference(ResourceReference reference,
		PageParameters pageParameters, String media)
	{
		return forReference(reference, pageParameters, media, null);
	}

	/**
	 * Creates a {@link CssReferenceHeaderItem} for the given reference.
	 *
	 * Warning: the conditional comments don't work when injected dynamically
	 * with JavaScript (i.e. in Ajax response). An alternative solution is to use user agent sniffing
	 * at the server side:
	 * 	 * public void renderHead(IHeaderResponse response) {
	 *   WebClientInfo clientInfo = (WebClientInfo) getSession().getClientInfo();
	 *   ClientProperties properties = clientInfo.getProperties();
	 *   if (properties.isBrowserInternetExplorer() && properties.getBrowserVersionMajor() >= 8) {
	 *     response.renderCSSReference(new PackageResourceReference(MyPage.class, "my-conditional.css" ));
	 *   }
	 * }
	 * 
	 *
	 * @param reference
	 *            a reference to a CSS resource
	 * @param pageParameters
	 *            the parameters for this CSS resource reference
	 * @param media
	 *            the media type for this CSS ("print", "screen", etc.)
	 * @param condition
	 *            the condition to use for Internet Explorer conditional comments. E.g. "IE 7".
	 * @return A newly created {@link CssReferenceHeaderItem} for the given reference.
	 */
	public static CssReferenceHeaderItem forReference(ResourceReference reference,
		PageParameters pageParameters, String media, String condition)
	{
		return new CssReferenceHeaderItem(reference, pageParameters, media, condition);
	}

	/**
	 * Creates a {@link CssContentHeaderItem} for the given content.
	 * 
	 * @param css
	 *            css content to be rendered.
	 * @param id
	 *            unique id for the <style> element. This can be null, however in
	 *            that case the ajax header contribution can't detect duplicate CSS fragments.
	 * @return A newly created {@link CssContentHeaderItem} for the given content.
	 */
	public static CssContentHeaderItem forCSS(CharSequence css, String id)
	{
		return forCSS(css, id, null);
	}


	/**
	 * Creates a {@link CssContentHeaderItem} for the given content.
	 *
	 * Warning: the conditional comments don't work when injected dynamically
	 * with JavaScript (i.e. in Ajax response). An alternative solution is to use user agent sniffing
	 * at the server side:
	 * 	 * public void renderHead(IHeaderResponse response) {
	 *   WebClientInfo clientInfo = (WebClientInfo) getSession().getClientInfo();
	 *   ClientProperties properties = clientInfo.getProperties();
	 *   if (properties.isBrowserInternetExplorer() && properties.getBrowserVersionMajor() >= 8) {
	 *     response.renderCSSReference(new PackageResourceReference(MyPage.class, "my-conditional.css" ));
	 *   }
	 * }
	 * 
	 *
	 * @param css
	 *            css content to be rendered.
	 * @param id
	 *            unique id for the <style> element. This can be null, however in
	 *            that case the ajax header contribution can't detect duplicate CSS fragments.
	 * @param condition
	 *            the condition to use for Internet Explorer conditional comments. E.g. "IE 7".
	 * @return A newly created {@link CssContentHeaderItem} for the given content.
	 */
	public static CssContentHeaderItem forCSS(CharSequence css, String id, String condition)
	{
		return new CssContentHeaderItem(css, id, condition);
	}
	
	/**
	 * Creates a {@link CssUrlReferenceHeaderItem} for the given url.
	 * 
	 * @param url
	 *            context-relative url of the CSS resource
	 * @return A newly created {@link CssUrlReferenceHeaderItem} for the given url.
	 */
	public static CssUrlReferenceHeaderItem forUrl(String url)
	{
		return forUrl(url, null);
	}

	/**
	 * Creates a {@link CssUrlReferenceHeaderItem} for the given url.
	 * 
	 * @param url
	 *            context-relative url of the CSS resource
	 * @param media
	 *            the media type for this CSS ("print", "screen", etc.)
	 * @return A newly created {@link CssUrlReferenceHeaderItem} for the given url.
	 */
	public static CssUrlReferenceHeaderItem forUrl(String url, String media)
	{
		return forUrl(url, media, null);
	}

	/**
	 * Creates a {@link CssUrlReferenceHeaderItem} for the given url.
	 *
	 * Warning: the conditional comments don't work when injected dynamically
	 * with JavaScript (i.e. in Ajax response). An alternative solution is to use user agent sniffing
	 * at the server side:
	 * 	 * public void renderHead(IHeaderResponse response) {
	 *   WebClientInfo clientInfo = (WebClientInfo) getSession().getClientInfo();
	 *   ClientProperties properties = clientInfo.getProperties();
	 *   if (properties.isBrowserInternetExplorer() && properties.getBrowserVersionMajor() >= 8) {
	 *     response.renderCSSReference(new PackageResourceReference(MyPage.class, "my-conditional.css" ));
	 *   }
	 * }
	 * 
	 *
	 * @param url
	 *            context-relative url of the CSS resource
	 * @param media
	 *            the media type for this CSS ("print", "screen", etc.)
	 * @param condition
	 *            the condition to use for Internet Explorer conditional comments. E.g. "IE 7".
	 * @return A newly created {@link CssUrlReferenceHeaderItem} for the given url.
	 */
	public static CssUrlReferenceHeaderItem forUrl(String url, String media, String condition)
	{
		return new CssUrlReferenceHeaderItem(url, media, condition);
	}

	protected final void internalRenderCSSReference(Response response, String url, String media,
		String condition)
	{
		Args.notEmpty(url, "url");
		
		boolean hasCondition = Strings.isEmpty(condition) == false; 
		if (hasCondition)
		{
			if (RequestCycle.get().find(AjaxRequestTarget.class) != null)
			{
				// WICKET-4894
				logger.warn("IE CSS engine doesn't support dynamically injected links in " +
						"conditional comments. See the javadoc of IHeaderResponse for alternative solution.");
			}


			response.write("");
		}
		response.write("\n");
	}
}