org.springframework.web.servlet.tags.NestedPathTag Maven / Gradle / Ivy
/*
* Copyright 2002-2005 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 javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.TagSupport;
import org.springframework.validation.Errors;
import org.springframework.web.util.ExpressionEvaluationUtils;
/**
* Nested-path tag, to support and assist with nested beans or bean properties
* in the model. Exports a "nestedPath" variable of type String in request scope,
* visible to the current page and also included pages, if any.
*
*
The BindTag will auto-detect the current nested path and automatically
* prepend it to its own path to form a complete path to the bean or bean property.
*
*
This tag will also prepend any existing nested path that is currently set.
* Thus, you can nest multiple nested-path tags.
*
*
Thanks to Seth Ladd for the suggestion and the original implementation!
*
* @author Juergen Hoeller
* @since 1.1
*/
public class NestedPathTag extends TagSupport {
/**
* Name of the exposed variable within the scope of this tag: "nestedPath".
*/
public static final String NESTED_PATH_VARIABLE_NAME = "nestedPath";
private String path;
/** To cache any previous nested path, so that it may be reset */
private String previousNestedPath = "";
/**
* Set the path that this tag should apply.
*
E.g. "customer" to allow bind paths like "address.street"
* rather than "customer.address.street".
* @see BindTag#setPath
*/
public void setPath(String path) {
if (path == null) {
path = "";
}
if (path.length() > 0 && !path.endsWith(Errors.NESTED_PATH_SEPARATOR)) {
path += Errors.NESTED_PATH_SEPARATOR;
}
this.path = path;
}
/**
* Return the path that this tag applies to.
*/
public String getPath() {
return path;
}
public int doStartTag() throws JspException {
String resolvedPath = ExpressionEvaluationUtils.evaluateString("path", getPath(), pageContext);
// Save previous nestedPath value, build and expose current nestedPath value.
// Use request scope to expose nestedPath to included pages too.
String nestedPath = (String) pageContext.getAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
if (nestedPath != null) {
this.previousNestedPath = nestedPath;
nestedPath = nestedPath + resolvedPath;
}
else {
nestedPath = resolvedPath;
}
pageContext.setAttribute(NESTED_PATH_VARIABLE_NAME, nestedPath, PageContext.REQUEST_SCOPE);
return EVAL_BODY_INCLUDE;
}
/**
* Reset any previous nestedPath value.
*/
public int doEndTag() {
if (this.previousNestedPath != null) {
// Expose previous nestedPath value.
pageContext.setAttribute(NESTED_PATH_VARIABLE_NAME, this.previousNestedPath, PageContext.REQUEST_SCOPE);
}
else {
// Remove exposed nestedPath value.
pageContext.removeAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
}
return EVAL_PAGE;
}
}