📄 htmlheaderresolver.java
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/* * 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.resolver;import org.apache.wicket.MarkupContainer;import org.apache.wicket.WicketRuntimeException;import org.apache.wicket.markup.ComponentTag;import org.apache.wicket.markup.MarkupException;import org.apache.wicket.markup.MarkupStream;import org.apache.wicket.markup.WicketTag;import org.apache.wicket.markup.html.WebMarkupContainer;import org.apache.wicket.markup.html.WebPage;import org.apache.wicket.markup.html.internal.HtmlHeaderContainer;import org.apache.wicket.markup.parser.filter.HtmlHeaderSectionHandler;import org.apache.wicket.markup.parser.filter.WicketTagIdentifier;/** * This is a tag resolver which handles <head> and <wicket:head>tags. It must be * registered (with the application) and assumes that a ComponentTag respectively a WicketTag has * already been created (see HtmlheaderSectionHandler and WicketTagIdentifier). * <p> * Provided the current tag is a <head>, a HtmlHeaderContainer component is created, (auto) * added to the component hierarchie and immediately rendered. Please see the javadoc for * HtmlHeaderContainer on how it treats the tag. * <p> * In case of <wicket:head> a simple WebMarkupContainer handles the tag. * * @author Juergen Donnerstag */public class HtmlHeaderResolver implements IComponentResolver{ private static final long serialVersionUID = 1L; static { // register "wicket:head" WicketTagIdentifier.registerWellKnownTagName("head"); } /** * Try to resolve the tag, then create a component, add it to the container and render it. * * @see org.apache.wicket.markup.resolver.IComponentResolver#resolve(MarkupContainer, * MarkupStream, ComponentTag) * * @param container * The container parsing its markup * @param markupStream * The current markupStream * @param tag * The current component tag while parsing the markup * @return true, if componentId was handle by the resolver. False, otherwise */ public boolean resolve(final MarkupContainer container, final MarkupStream markupStream, final ComponentTag tag) { // Only <head> component tags have the id == "_header" if (tag.getId().equals(HtmlHeaderSectionHandler.HEADER_ID)) { // Create a special header component which will gather additional // input the <head> from 'contributors'. final WebMarkupContainer header = new HtmlHeaderContainer( HtmlHeaderSectionHandler.HEADER_ID + container.getPage().getAutoIndex()); container.autoAdd(header, markupStream); // Yes, we handled the tag return true; } else if ((tag instanceof WicketTag) && ((WicketTag)tag).isHeadTag()) { // If we found <wicket:head> without surrounding <head> on a Page, // than we have to add wicket:head into a automatically generated // head first. if (container instanceof WebPage) { // Create a special header component which will gather // additional input the <head> from 'contributors'. final MarkupContainer header = new HtmlHeaderContainer( HtmlHeaderSectionHandler.HEADER_ID + container.getPage().getAutoIndex()); // It is <wicket:head>. Because they do not provide any // additional functionality they are merely a means of surrounding relevant // markup. Thus we simply create a WebMarkupContainer to handle // the tag. final WebMarkupContainer header2 = new WebMarkupContainer( HtmlHeaderSectionHandler.HEADER_ID) { private static final long serialVersionUID = 1L; public boolean isTransparentResolver() { return true; } }; header2.setRenderBodyOnly(true); header.add(header2); container.autoAdd(header, markupStream); } else if (container instanceof HtmlHeaderContainer) { // It is <wicket:head>. Because they do not provide any // additional functionality there are merely a means of surrounding // relevant markup. Thus we simply create a WebMarkupContainer to handle // the tag. final WebMarkupContainer header = new WebMarkupContainer( HtmlHeaderSectionHandler.HEADER_ID) { private static final long serialVersionUID = 1L; public boolean isTransparentResolver() { return true; } }; header.setRenderBodyOnly(true); try { container.autoAdd(header, markupStream); } catch (IllegalArgumentException ex) { throw new WicketRuntimeException("If the root exception says something like " + "\"A child with id '_header' already exists\" " + "then you most likely forgot to override autoAdd() " + "in your bordered page component.", ex); } } else { throw new MarkupException( "Mis-placed <wicket:head>. <wicket:head> must be outside of <wicket:panel> and <wicket:border>"); } // Yes, we handled the tag return true; } // We were not able to handle the tag return false; }}⌨️ 快捷键说明
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