📄 containerwithassociatedmarkuphelper.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.html;import org.apache.wicket.Response;import org.apache.wicket.WicketRuntimeException;import org.apache.wicket.behavior.AbstractBehavior;import org.apache.wicket.markup.ComponentTag;import org.apache.wicket.markup.MarkupElement;import org.apache.wicket.markup.MarkupException;import org.apache.wicket.markup.MarkupStream;import org.apache.wicket.markup.TagUtils;import org.apache.wicket.markup.WicketTag;import org.apache.wicket.markup.html.internal.HtmlHeaderContainer;import org.apache.wicket.response.NullResponse;import org.apache.wicket.util.lang.Classes;/** * A Wicket internal helper class to handle wicket:head tags. * * @author Juergen Donnerstag */public class ContainerWithAssociatedMarkupHelper extends AbstractBehavior{ private static final long serialVersionUID = 1L; /** <wicket:head> is only allowed before <body>, </head>, <wicket:panel> etc. */ private boolean noMoreWicketHeadTagsAllowed = false; /** The markup container the helper is associated with */ private final WebMarkupContainer container; /** * @param container */ public ContainerWithAssociatedMarkupHelper(final IHeaderPartContainerProvider container) { this.container = (WebMarkupContainer)container; } /** * Called by components like Panel and Border which have associated Markup and which may have a * <wicket:head> tag. * <p> * Whereas 'this' might be a Panel or Border, the HtmlHeaderContainer parameter has been added * to the Page as a container for all headers any of its components might wish to contribute. * <p> * The headers contributed are rendered in the standard way. * * @param htmlContainer * The HtmlHeaderContainer added to the Page */ public final void renderHeadFromAssociatedMarkupFile(final HtmlHeaderContainer htmlContainer) { // Gracefully getAssociateMarkupStream. Throws no exception in case // markup is not found final MarkupStream markupStream = container.getAssociatedMarkupStream(false); // No associated markup => no header section if (markupStream == null) { return; } // Position pointer at current (first) header noMoreWicketHeadTagsAllowed = false; while (nextHeaderMarkup(markupStream) != -1) { Class markupClass = ((WicketTag)markupStream.getTag()).getMarkupClass(); if (markupClass == null) { markupClass = markupStream.getContainerClass(); } // Create a HeaderPartContainer and associate the markup final HeaderPartContainer headerPart = getHeaderPart(markupClass, markupStream .getCurrentIndex()); if (headerPart != null) { // A component's header section must only be added once, // no matter how often the same Component has been added // to the page or any other container in the hierarchy. if (htmlContainer.okToRenderComponent(headerPart.getScope(), headerPart.getId())) { htmlContainer.autoAdd(headerPart, null); } else { // TODO Performance: I haven't found a more efficient // solution yet. // Already added but all the components in this header part // must be touched (that they are rendered) Response response = container.getRequestCycle().getResponse(); try { container.getRequestCycle().setResponse(NullResponse.getInstance()); htmlContainer.autoAdd(headerPart, null); } finally { container.getRequestCycle().setResponse(response); } } } // Position the stream after <wicket:head> markupStream.skipComponent(); } } /** * Gets the header part of the Panel/Border. Returns null if it doesn't have a header tag. * * @param index * A unique index * @param markupClass * The java class the wicket:head tag is directly associated with * @return the header part for this panel/border or null if it doesn't have a wicket:head tag. */ private final HeaderPartContainer getHeaderPart(final Class markupClass, final int index) { // Gracefully getAssociateMarkupStream. Throws no exception in case // markup is not found final MarkupStream markupStream = container.getAssociatedMarkupStream(false); // Position markup stream at beginning of header tag markupStream.setCurrentIndex(index); // Create a HtmlHeaderContainer for the header tag found final MarkupElement element = markupStream.get(); if (element instanceof WicketTag) { final WicketTag wTag = (WicketTag)element; if ((wTag.isHeadTag() == true) && (wTag.getNamespace() != null)) { // found <wicket:head> // create a unique id for the HtmlHeaderContainer to be // created final String headerId = "_" + Classes.simpleName(markupClass) + container.getVariation() + "Header" + index; // Create the header container and associate the markup with // it String scope = wTag.getAttributes().getString( markupStream.getWicketNamespace() + ":scope"); final HeaderPartContainer headerContainer = ((IHeaderPartContainerProvider)container) .newHeaderPartContainer(headerId, scope); headerContainer.setMyMarkupStream(markupStream); headerContainer.setRenderBodyOnly(true); // The container does have a header component return headerContainer; } } throw new WicketRuntimeException("Programming error: expected a WicketTag: " + markupStream.toString()); } /** * Process next header markup fragment. * * @param associatedMarkupStream * @return index or -1 when done */ private final int nextHeaderMarkup(final MarkupStream associatedMarkupStream) { // No associated markup => no header section if (associatedMarkupStream == null) { return -1; } // Scan the markup for <wicket:head>. MarkupElement elem = associatedMarkupStream.get(); while (elem != null) { if (elem instanceof WicketTag) { WicketTag tag = (WicketTag)elem; if (tag.isOpen() && tag.isHeadTag()) { if (noMoreWicketHeadTagsAllowed == true) { throw new MarkupException( "<wicket:head> tags are only allowed before <body>, </head>, <wicket:panel> etc. tag"); } return associatedMarkupStream.getCurrentIndex(); } // wicket:head must be before border, panel or extend else if (tag.isOpen() && (tag.isPanelTag() || tag.isBorderTag() || tag.isExtendTag())) { noMoreWicketHeadTagsAllowed = true; } } else if (elem instanceof ComponentTag) { ComponentTag tag = (ComponentTag)elem; // wicket:head must be before </head> if (tag.isClose() && TagUtils.isHeadTag(tag)) { noMoreWicketHeadTagsAllowed = true; } // wicket:head must be before <body> else if (tag.isOpen() && TagUtils.isBodyTag(tag)) { noMoreWicketHeadTagsAllowed = true; } } elem = associatedMarkupStream.next(); } // No (more) wicket:head found return -1; }}⌨️ 快捷键说明
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