org.springframework.web.servlet.config.annotation.ViewControllerRegistry.java Source code

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Here is the source code for org.springframework.web.servlet.config.annotation.ViewControllerRegistry.java

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/*
 * 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.config.annotation;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.springframework.context.ApplicationContext;
import org.springframework.http.HttpStatus;
import org.springframework.lang.Nullable;
import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;

/**
 * Assists with the registration of simple automated controllers pre-configured
 * with status code and/or a view.
 *
 * @author Rossen Stoyanchev
 * @author Keith Donald
 * @since 3.1
 */
public class ViewControllerRegistry {

    @Nullable
    private ApplicationContext applicationContext;

    private final List<ViewControllerRegistration> registrations = new ArrayList<>(4);

    private final List<RedirectViewControllerRegistration> redirectRegistrations = new ArrayList<>(10);

    private int order = 1;

    /**
     * Class constructor with {@link ApplicationContext}.
     * @since 4.3.12
     */
    public ViewControllerRegistry(@Nullable ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    /**
     * Map a view controller to the given URL path (or pattern) in order to render
     * a response with a pre-configured status code and view.
     * <p>Patterns like {@code "/admin/**"} or {@code "/articles/{articlename:\\w+}"}
     * are allowed. See {@link org.springframework.util.AntPathMatcher} for more details on the
     * syntax.
     */
    public ViewControllerRegistration addViewController(String urlPath) {
        ViewControllerRegistration registration = new ViewControllerRegistration(urlPath);
        registration.setApplicationContext(this.applicationContext);
        this.registrations.add(registration);
        return registration;
    }

    /**
     * Map a view controller to the given URL path (or pattern) in order to redirect
     * to another URL. By default the redirect URL is expected to be relative to
     * the current ServletContext, i.e. as relative to the web application root.
     * @since 4.1
     */
    public RedirectViewControllerRegistration addRedirectViewController(String urlPath, String redirectUrl) {
        RedirectViewControllerRegistration registration = new RedirectViewControllerRegistration(urlPath,
                redirectUrl);
        registration.setApplicationContext(this.applicationContext);
        this.redirectRegistrations.add(registration);
        return registration;
    }

    /**
     * Map a simple controller to the given URL path (or pattern) in order to
     * set the response status to the given code without rendering a body.
     * @since 4.1
     */
    public void addStatusController(String urlPath, HttpStatus statusCode) {
        ViewControllerRegistration registration = new ViewControllerRegistration(urlPath);
        registration.setApplicationContext(this.applicationContext);
        registration.setStatusCode(statusCode);
        registration.getViewController().setStatusOnly(true);
        this.registrations.add(registration);
    }

    /**
     * Specify the order to use for the {@code HandlerMapping} used to map view
     * controllers relative to other handler mappings configured in Spring MVC.
     * <p>By default this is set to 1, i.e. right after annotated controllers,
     * which are ordered at 0.
     */
    public void setOrder(int order) {
        this.order = order;
    }

    /**
     * Return the {@code HandlerMapping} that contains the registered view
     * controller mappings, or {@code null} for no registrations.
     * @since 4.3.12
     */
    @Nullable
    protected SimpleUrlHandlerMapping buildHandlerMapping() {
        if (this.registrations.isEmpty() && this.redirectRegistrations.isEmpty()) {
            return null;
        }

        Map<String, Object> urlMap = new LinkedHashMap<>();
        for (ViewControllerRegistration registration : this.registrations) {
            urlMap.put(registration.getUrlPath(), registration.getViewController());
        }
        for (RedirectViewControllerRegistration registration : this.redirectRegistrations) {
            urlMap.put(registration.getUrlPath(), registration.getViewController());
        }

        return new SimpleUrlHandlerMapping(urlMap, this.order);
    }

}