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Spring Framework example source code file (AbstractHtmlElementBodyTag.java)
The Spring Framework AbstractHtmlElementBodyTag.java source code/* * Copyright 2002-2007 the original author or authors. * * Licensed 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.springframework.web.servlet.tags.form; import java.io.IOException; import javax.servlet.jsp.JspException; import javax.servlet.jsp.tagext.BodyContent; import javax.servlet.jsp.tagext.BodyTag; import org.springframework.util.StringUtils; /** * Convenient super class for many html tags that render content using the databinding * features of the {@link AbstractHtmlElementTag AbstractHtmlElementTag}. The only thing sub tags * need to do is override {@link #renderDefaultContent(TagWriter)}. * * @author Rob Harrop * @author Juergen Hoeller * @since 2.0 */ public abstract class AbstractHtmlElementBodyTag extends AbstractHtmlElementTag implements BodyTag { private BodyContent bodyContent; private TagWriter tagWriter; protected int writeTagContent(TagWriter tagWriter) throws JspException { onWriteTagContent(); this.tagWriter = tagWriter; if (shouldRender()) { exposeAttributes(); return EVAL_BODY_BUFFERED; } else { return EVAL_PAGE; } } /** * If {@link #shouldRender rendering}, flush any buffered * {@link BodyContent} or, if no {@link BodyContent} is supplied, * {@link #renderDefaultContent render the default content}. * @return Tag#EVAL_PAGE */ public int doEndTag() throws JspException { if (shouldRender()) { if (this.bodyContent != null && StringUtils.hasText(this.bodyContent.getString())) { renderFromBodyContent(this.bodyContent, this.tagWriter); } else { renderDefaultContent(this.tagWriter); } } return EVAL_PAGE; } /** * Render the tag contents based on the supplied {@link BodyContent}. * <p>The default implementation simply {@link #flushBufferedBodyContent flushes} * the {@link BodyContent} directly to the output. Subclasses may choose to * override this to add additional content to the output. */ protected void renderFromBodyContent(BodyContent bodyContent, TagWriter tagWriter) throws JspException { flushBufferedBodyContent(this.bodyContent); } /** * Clean up any attributes and stored resources. */ public void doFinally() { super.doFinally(); removeAttributes(); this.tagWriter = null; this.bodyContent = null; } //--------------------------------------------------------------------- // Template methods //--------------------------------------------------------------------- /** * Called at the start of {@link #writeTagContent} allowing subclasses to perform * any precondition checks or setup tasks that might be necessary. */ protected void onWriteTagContent() { } /** * Should rendering of this tag proceed at all. Returns '<code>true' by default * causing rendering to occur always, Subclasses can override this if they * provide conditional rendering. */ protected boolean shouldRender() throws JspException { return true; } /** * Called during {@link #writeTagContent} allowing subclasses to add any attributes to the * {@link javax.servlet.jsp.PageContext} as needed. */ protected void exposeAttributes() throws JspException { } /** * Called by {@link #doFinally} allowing subclasses to remove any attributes from the * {@link javax.servlet.jsp.PageContext} as needed. */ protected void removeAttributes() { } /** * The user customised the output of the error messages - flush the * buffered content into the main {@link javax.servlet.jsp.JspWriter}. */ protected void flushBufferedBodyContent(BodyContent bodyContent) throws JspException { try { bodyContent.writeOut(bodyContent.getEnclosingWriter()); } catch (IOException e) { throw new JspException("Unable to write buffered body content.", e); } } protected abstract void renderDefaultContent(TagWriter tagWriter) throws JspException; //--------------------------------------------------------------------- // BodyTag implementation //--------------------------------------------------------------------- public void doInitBody() throws JspException { // no op } public void setBodyContent(BodyContent bodyContent) { this.bodyContent = bodyContent; } } Other Spring Framework examples (source code examples)Here is a short list of links related to this Spring Framework AbstractHtmlElementBodyTag.java source code file: |
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