001/*
002 * Copyright 2002-2012 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.servlet.tags;
018
019import javax.servlet.jsp.JspException;
020import javax.servlet.jsp.PageContext;
021import javax.servlet.jsp.tagext.TagSupport;
022import javax.servlet.jsp.tagext.TryCatchFinally;
023
024import org.springframework.beans.PropertyAccessor;
025
026/**
027 * <p>Nested-path tag, to support and assist with nested beans or bean properties
028 * in the model. Exports a "nestedPath" variable of type String in request scope,
029 * visible to the current page and also included pages, if any.
030 *
031 * <p>The BindTag will auto-detect the current nested path and automatically
032 * prepend it to its own path to form a complete path to the bean or bean property.
033 *
034 * <p>This tag will also prepend any existing nested path that is currently set.
035 * Thus, you can nest multiple nested-path tags.
036 *
037 * <p>Thanks to Seth Ladd for the suggestion and the original implementation!
038 *
039 * @author Juergen Hoeller
040 * @since 1.1
041 */
042@SuppressWarnings("serial")
043public class NestedPathTag extends TagSupport implements TryCatchFinally {
044
045        /**
046         * Name of the exposed variable within the scope of this tag: "nestedPath".
047         */
048        public static final String NESTED_PATH_VARIABLE_NAME = "nestedPath";
049
050
051        private String path;
052
053        /** Caching a previous nested path, so that it may be reset */
054        private String previousNestedPath;
055
056
057        /**
058         * Set the path that this tag should apply.
059         * <p>E.g. "customer" to allow bind paths like "address.street"
060         * rather than "customer.address.street".
061         * @see BindTag#setPath
062         */
063        public void setPath(String path) {
064                if (path == null) {
065                        path = "";
066                }
067                if (path.length() > 0 && !path.endsWith(PropertyAccessor.NESTED_PROPERTY_SEPARATOR)) {
068                        path += PropertyAccessor.NESTED_PROPERTY_SEPARATOR;
069                }
070                this.path = path;
071        }
072
073        /**
074         * Return the path that this tag applies to.
075         */
076        public String getPath() {
077                return this.path;
078        }
079
080
081        @Override
082        public int doStartTag() throws JspException {
083                // Save previous nestedPath value, build and expose current nestedPath value.
084                // Use request scope to expose nestedPath to included pages too.
085                this.previousNestedPath =
086                                (String) pageContext.getAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
087                String nestedPath =
088                                (this.previousNestedPath != null ? this.previousNestedPath + getPath() : getPath());
089                pageContext.setAttribute(NESTED_PATH_VARIABLE_NAME, nestedPath, PageContext.REQUEST_SCOPE);
090
091                return EVAL_BODY_INCLUDE;
092        }
093
094        /**
095         * Reset any previous nestedPath value.
096         */
097        @Override
098        public int doEndTag() {
099                if (this.previousNestedPath != null) {
100                        // Expose previous nestedPath value.
101                        pageContext.setAttribute(NESTED_PATH_VARIABLE_NAME, this.previousNestedPath, PageContext.REQUEST_SCOPE);
102                }
103                else {
104                        // Remove exposed nestedPath value.
105                        pageContext.removeAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
106                }
107
108                return EVAL_PAGE;
109        }
110
111        @Override
112        public void doCatch(Throwable throwable) throws Throwable {
113                throw throwable;
114        }
115
116        @Override
117        public void doFinally() {
118                this.previousNestedPath = null;
119        }
120
121}