org.springframework.web.servlet.tags.NestedPathTag Maven / Gradle / Ivy
/*
* 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
*
* https://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 javax.servlet.jsp.tagext.TryCatchFinally;
import org.springframework.beans.PropertyAccessor;
import org.springframework.lang.Nullable;
/**
* The {@code } tag supports and assists 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.
*
*
* Attribute Summary
*
*
* Attribute
* Required?
* Runtime Expression?
* Description
*
*
*
*
* path
* true
* true
* Set the path that this tag should apply. E.g. 'customer' to allow bind
* paths like 'address.street' rather than 'customer.address.street'.
*
*
*
*
* @author Juergen Hoeller
* @since 1.1
*/
@SuppressWarnings("serial")
public class NestedPathTag extends TagSupport implements TryCatchFinally {
/**
* Name of the exposed variable within the scope of this tag: "nestedPath".
*/
public static final String NESTED_PATH_VARIABLE_NAME = "nestedPath";
@Nullable
private String path;
/** Caching a previous nested path, so that it may be reset. */
@Nullable
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(@Nullable String path) {
if (path == null) {
path = "";
}
if (path.length() > 0 && !path.endsWith(PropertyAccessor.NESTED_PROPERTY_SEPARATOR)) {
path += PropertyAccessor.NESTED_PROPERTY_SEPARATOR;
}
this.path = path;
}
/**
* Return the path that this tag applies to.
*/
@Nullable
public String getPath() {
return this.path;
}
@Override
public int doStartTag() throws JspException {
// Save previous nestedPath value, build and expose current nestedPath value.
// Use request scope to expose nestedPath to included pages too.
this.previousNestedPath =
(String) this.pageContext.getAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
String nestedPath =
(this.previousNestedPath != null ? this.previousNestedPath + getPath() : getPath());
this.pageContext.setAttribute(NESTED_PATH_VARIABLE_NAME, nestedPath, PageContext.REQUEST_SCOPE);
return EVAL_BODY_INCLUDE;
}
/**
* Reset any previous nestedPath value.
*/
@Override
public int doEndTag() {
if (this.previousNestedPath != null) {
// Expose previous nestedPath value.
this.pageContext.setAttribute(NESTED_PATH_VARIABLE_NAME, this.previousNestedPath, PageContext.REQUEST_SCOPE);
}
else {
// Remove exposed nestedPath value.
this.pageContext.removeAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
}
return EVAL_PAGE;
}
@Override
public void doCatch(Throwable throwable) throws Throwable {
throw throwable;
}
@Override
public void doFinally() {
this.previousNestedPath = null;
}
}