com.boundlessgeo.geoserver.api.controllers.ConfigurationLockInterceptor.java Source code

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Here is the source code for com.boundlessgeo.geoserver.api.controllers.ConfigurationLockInterceptor.java

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/* (c) 2015 Boundless, http://boundlessgeo.com
 * This code is licensed under the GPL 2.0 license.
 */
package com.boundlessgeo.geoserver.api.controllers;

import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.geoserver.GeoServerConfigurationLock;
import org.geoserver.platform.GeoServerExtensions;
import org.geotools.util.logging.Logging;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

/**
 * Inspired by the RestConfigurationLockCallback.
 */
public class ConfigurationLockInterceptor extends HandlerInterceptorAdapter {

    // visible for testing
    final ThreadLocal<GeoServerConfigurationLock.LockType> THREAD_LOCK = new ThreadLocal<>();

    private GeoServerConfigurationLock lock;

    private static final Logger logger = Logging.getLogger(ConfigurationLockInterceptor.class);

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
            Exception ex) throws Exception {
        // @todo - async post operations will get unlocked before critical section!
        //         this applies to importing as of writing. since the lock is
        //         reentrant, nested locks don't hurt
        GeoServerConfigurationLock.LockType lockType = THREAD_LOCK.get();
        if (lockType != null) {
            THREAD_LOCK.remove();
            lock.unlock(lockType);
        }
    }

    GeoServerConfigurationLock lock() {
        if (lock == null) {
            lock = GeoServerExtensions.bean(GeoServerConfigurationLock.class);
        }
        return lock;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        if (THREAD_LOCK.get() != null) {
            throw new RuntimeException("existing lock found on " + request.getPathInfo());
        }
        String method = request.getMethod().toLowerCase();
        GeoServerConfigurationLock.LockType lockType;
        switch (method) {
        case "get":
        case "head":
        case "options":
            lockType = GeoServerConfigurationLock.LockType.READ;
            break;
        default:
            // defaulting to a write lock is probably the safest bet here
            // unless a new, popular read method is invented sometime...
            lockType = GeoServerConfigurationLock.LockType.WRITE;
        }
        if (logger.isLoggable(Level.FINE)) {
            logger.fine("DEBUG LOCK: " + lockType);
        }
        THREAD_LOCK.set(lockType);
        lock().lock(lockType);
        return true;
    }

}