001/*
002 * Copyright 2002-2018 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.reactive;
018
019import org.springframework.lang.Nullable;
020import org.springframework.ui.Model;
021import org.springframework.validation.support.BindingAwareConcurrentModel;
022import org.springframework.web.bind.support.WebBindingInitializer;
023import org.springframework.web.bind.support.WebExchangeDataBinder;
024import org.springframework.web.server.ServerErrorException;
025import org.springframework.web.server.ServerWebExchange;
026
027/**
028 * Context to assist with binding request data onto Objects and provide access
029 * to a shared {@link Model} with controller-specific attributes.
030 *
031 * <p>Provides  methods to create a {@link WebExchangeDataBinder} for a specific
032 * target, command Object to apply data binding and validation to, or without a
033 * target Object for simple type conversion from request values.
034 *
035 * <p>Container for the default model for the request.
036 *
037 * @author Rossen Stoyanchev
038 * @since 5.0
039 */
040public class BindingContext {
041
042        @Nullable
043        private final WebBindingInitializer initializer;
044
045        private final Model model = new BindingAwareConcurrentModel();
046
047
048        /**
049         * Create a new {@code BindingContext}.
050         */
051        public BindingContext() {
052                this(null);
053        }
054
055        /**
056         * Create a new {@code BindingContext} with the given initializer.
057         * @param initializer the binding initializer to apply (may be {@code null})
058         */
059        public BindingContext(@Nullable WebBindingInitializer initializer) {
060                this.initializer = initializer;
061        }
062
063
064        /**
065         * Return the default model.
066         */
067        public Model getModel() {
068                return this.model;
069        }
070
071
072        /**
073         * Create a {@link WebExchangeDataBinder} to apply data binding and
074         * validation with on the target, command object.
075         * @param exchange the current exchange
076         * @param target the object to create a data binder for
077         * @param name the name of the target object
078         * @return the created data binder
079         * @throws ServerErrorException if {@code @InitBinder} method invocation fails
080         */
081        public WebExchangeDataBinder createDataBinder(ServerWebExchange exchange, @Nullable Object target, String name) {
082                WebExchangeDataBinder dataBinder = new WebExchangeDataBinder(target, name);
083                if (this.initializer != null) {
084                        this.initializer.initBinder(dataBinder);
085                }
086                return initDataBinder(dataBinder, exchange);
087        }
088
089        /**
090         * Initialize the data binder instance for the given exchange.
091         * @throws ServerErrorException if {@code @InitBinder} method invocation fails
092         */
093        protected WebExchangeDataBinder initDataBinder(WebExchangeDataBinder binder, ServerWebExchange exchange) {
094                return binder;
095        }
096
097        /**
098         * Create a {@link WebExchangeDataBinder} without a target object for type
099         * conversion of request values to simple types.
100         * @param exchange the current exchange
101         * @param name the name of the target object
102         * @return the created data binder
103         * @throws ServerErrorException if {@code @InitBinder} method invocation fails
104         */
105        public WebExchangeDataBinder createDataBinder(ServerWebExchange exchange, String name) {
106                return createDataBinder(exchange, null, name);
107        }
108
109}