org.springframework.web.context.request.AbstractRequestAttributes.java Source code

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Here is the source code for org.springframework.web.context.request.AbstractRequestAttributes.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.context.request;

import java.util.LinkedHashMap;
import java.util.Map;

import org.springframework.util.Assert;

/**
 * Abstract support class for RequestAttributes implementations,
 * offering a request completion mechanism for request-specific destruction
 * callbacks and for updating accessed session attributes.
 *
 * @author Juergen Hoeller
 * @since 2.0
 * @see #requestCompleted()
 */
public abstract class AbstractRequestAttributes implements RequestAttributes {

    /** Map from attribute name String to destruction callback Runnable. */
    protected final Map<String, Runnable> requestDestructionCallbacks = new LinkedHashMap<>(8);

    private volatile boolean requestActive = true;

    /**
     * Signal that the request has been completed.
     * <p>Executes all request destruction callbacks and updates the
     * session attributes that have been accessed during request processing.
     */
    public void requestCompleted() {
        executeRequestDestructionCallbacks();
        updateAccessedSessionAttributes();
        this.requestActive = false;
    }

    /**
     * Determine whether the original request is still active.
     * @see #requestCompleted()
     */
    protected final boolean isRequestActive() {
        return this.requestActive;
    }

    /**
     * Register the given callback as to be executed after request completion.
     * @param name the name of the attribute to register the callback for
     * @param callback the callback to be executed for destruction
     */
    protected final void registerRequestDestructionCallback(String name, Runnable callback) {
        Assert.notNull(name, "Name must not be null");
        Assert.notNull(callback, "Callback must not be null");
        synchronized (this.requestDestructionCallbacks) {
            this.requestDestructionCallbacks.put(name, callback);
        }
    }

    /**
     * Remove the request destruction callback for the specified attribute, if any.
     * @param name the name of the attribute to remove the callback for
     */
    protected final void removeRequestDestructionCallback(String name) {
        Assert.notNull(name, "Name must not be null");
        synchronized (this.requestDestructionCallbacks) {
            this.requestDestructionCallbacks.remove(name);
        }
    }

    /**
     * Execute all callbacks that have been registered for execution
     * after request completion.
     */
    private void executeRequestDestructionCallbacks() {
        synchronized (this.requestDestructionCallbacks) {
            for (Runnable runnable : this.requestDestructionCallbacks.values()) {
                runnable.run();
            }
            this.requestDestructionCallbacks.clear();
        }
    }

    /**
     * Update all session attributes that have been accessed during request processing,
     * to expose their potentially updated state to the underlying session manager.
     */
    protected abstract void updateAccessedSessionAttributes();

}