/*
 * 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 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 <nestedPath> 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/**
 * <p>The {@code <nestedPath>} 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.
 *
 * <p>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.
 *
 * <p>This tag will also prepend any existing nested path that is currently set.
 * Thus, you can nest multiple nested-path tags.
 *
 * <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>path</td>
 * <td>true</td>
 * <td>true</td>
 * <td>Set the path that this tag should apply. E.g. 'customer' to allow bind
 * paths like 'address.street' rather than 'customer.address.street'.</td>
 * </tr>
 * </tbody>
 * </table>
 *
 * @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".
/**
	 * 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. /** 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 Also:
setPath.setPath/**
	 * Set the path that this tag should apply.
	 * <p>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.
/**
	 * 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.
/**
	 * 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;
	}

}