/* * Copyright 2002-2018 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; import java.beans.PropertyEditor; import java.io.IOException; import javax.servlet.jsp.JspException; import javax.servlet.jsp.tagext.TagSupport; import org.springframework.lang.Nullable; import org.springframework.web.util.TagUtils; /** * The {@code <transform>} tag provides transformation for reference data values * from controllers and other objects inside a {@code spring:bind} tag (or a * data-bound form element tag from Spring's form tag library). * * <p>The BindTag has a PropertyEditor that it uses to transform properties of * a bean to a String, usable in HTML forms. This tag uses that PropertyEditor * to transform objects passed into this tag. * * <table> * <caption>Attribute Summary</caption> * <thead> * <tr> * <th>Attribute</th> * <th>Required?</th> * <th>Runtime Expression?</th> * <th>Description</th> * </tr> * </thead> * <tbody> * <tr> * <td>htmlEscape</td> * <td>false</td> * <td>true</td> * <td>Set HTML escaping for this tag, as boolean value. Overrides the default HTML * escaping setting for the current page.</td> * </tr> * <tr> * <td>scope</td> * <td>false</td> * <td>true</td> * <td>The scope to use when exported the result to a variable. This attribute * is only used when var is also set. Possible values are page, request, session * and application.</td> * </tr> * <tr> * <td>value</td> * <td>true</td> * <td>true</td> * <td>The value to transform. This is the actual object you want to have * transformed (for instance a Date). Using the PropertyEditor that is currently * in use by the 'spring:bind' tag.</td> * </tr> * <tr> * <td>var</td> * <td>false</td> * <td>true</td> * <td>The string to use when binding the result to the page, request, session * or application scope. If not specified, the result gets outputted to the * writer (i.e. typically directly to the JSP).</td> * </tr> * </tbody> * </table> * * @author Alef Arendsen * @author Juergen Hoeller * @since 20.09.2003 * @see BindTag */ @SuppressWarnings("serial") public class TransformTag extends HtmlEscapingAwareTag { /** the value to transform using the appropriate property editor. */ @Nullable private Object value; /** the variable to put the result in. */ @Nullable private String var; /** the scope of the variable the result will be put in. */ private String scope = TagUtils.SCOPE_PAGE; /** * Set the value to transform, using the appropriate PropertyEditor * from the enclosing BindTag. * <p>The value can either be a plain value to transform (a hard-coded String * value in a JSP or a JSP expression), or a JSP EL expression to be evaluated * (transforming the result of the expression). */ public void setValue(Object value) { this.value = value; } /** * Set PageContext attribute name under which to expose * a variable that contains the result of the transformation. * @see #setScope * @see javax.servlet.jsp.PageContext#setAttribute */ public void setVar(String var) { this.var = var; } /** * Set the scope to export the variable to. * Default is SCOPE_PAGE ("page"). * @see #setVar * @see org.springframework.web.util.TagUtils#SCOPE_PAGE * @see javax.servlet.jsp.PageContext#setAttribute */ public void setScope(String scope) { this.scope = scope; } @Override protected final int doStartTagInternal() throws JspException { if (this.value != null) { // Find the containing EditorAwareTag (e.g. BindTag), if applicable. EditorAwareTag tag = (EditorAwareTag) TagSupport.findAncestorWithClass(this, EditorAwareTag.class); if (tag == null) { throw new JspException("TransformTag can only be used within EditorAwareTag (e.g. BindTag)"); } // OK, let's obtain the editor... String result = null; PropertyEditor editor = tag.getEditor(); if (editor != null) { // If an editor was found, edit the value. editor.setValue(this.value); result = editor.getAsText(); } else { // Else, just do a toString. result = this.value.toString(); } result = htmlEscape(result); if (this.var != null) { this.pageContext.setAttribute(this.var, result, TagUtils.getScope(this.scope)); } else { try { // Else, just print it out. this.pageContext.getOut().print(result); } catch (IOException ex) { throw new JspException(ex); } } } return SKIP_BODY; } }