org.springframework.messaging.simp.SimpAttributesContextHolder.java Source code

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Here is the source code for org.springframework.messaging.simp.SimpAttributesContextHolder.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.messaging.simp;

import org.springframework.core.NamedThreadLocal;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;

/**
 * Holder class to expose SiMP attributes associated with a session (e.g. WebSocket)
 * in the form of a thread-bound {@link SimpAttributes} object.
 *
 * @author Rossen Stoyanchev
 * @since 4.1
 */
public abstract class SimpAttributesContextHolder {

    private static final ThreadLocal<SimpAttributes> attributesHolder = new NamedThreadLocal<>(
            "SiMP session attributes");

    /**
     * Reset the SimpAttributes for the current thread.
     */
    public static void resetAttributes() {
        attributesHolder.remove();
    }

    /**
     * Bind the given SimpAttributes to the current thread.
     * @param attributes the RequestAttributes to expose
     */
    public static void setAttributes(@Nullable SimpAttributes attributes) {
        if (attributes != null) {
            attributesHolder.set(attributes);
        } else {
            resetAttributes();
        }
    }

    /**
     * Extract the SiMP session attributes from the given message, wrap them in
     * a {@link SimpAttributes} instance and bind it to the current thread.
     * @param message the message to extract session attributes from
     */
    public static void setAttributesFromMessage(Message<?> message) {
        setAttributes(SimpAttributes.fromMessage(message));
    }

    /**
     * Return the SimpAttributes currently bound to the thread.
     * @return the attributes or {@code null} if not bound
     */
    @Nullable
    public static SimpAttributes getAttributes() {
        return attributesHolder.get();
    }

    /**
     * Return the SimpAttributes currently bound to the thread or raise an
     * {@link java.lang.IllegalStateException} if none are bound.
     * @return the attributes, never {@code null}
     * @throws java.lang.IllegalStateException if attributes are not bound
     */
    public static SimpAttributes currentAttributes() throws IllegalStateException {
        SimpAttributes attributes = getAttributes();
        if (attributes == null) {
            throw new IllegalStateException("No thread-bound SimpAttributes found. "
                    + "Your code is probably not processing a client message and executing in "
                    + "message-handling methods invoked by the SimpAnnotationMethodMessageHandler?");
        }
        return attributes;
    }

}