org.springframework.yarn.support.compat.NMTokenCacheCompat.java Source code

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Here is the source code for org.springframework.yarn.support.compat.NMTokenCacheCompat.java

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/*
 * Copyright 2013 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
 *
 *      http://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.yarn.support.compat;

import java.lang.reflect.Method;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.yarn.client.api.NMTokenCache;
import org.springframework.util.ReflectionUtils;

/**
 * Compat class for {@link NMTokenCache}.
 *
 * @author Janne Valkealahti
 * @author Thomas Risberg
 */
public class NMTokenCacheCompat {

    private final static Log log = LogFactory.getLog(NMTokenCacheCompat.class);

    private static NMTokenCache nmTokenCache;

    /** NMTokenCache init lock */
    private final static Object lock = new Object();

    /**
     * Gets the Hadoop {@code NMTokenCache}. Access token cache via singleton
     * method if exists, otherwise assumes that class is hadoop vanilla
     * implementation with static methods where we can just use default
     * constructor and further access for those static method would
     * got via instance itself.
     * <p>
     * This is due to a fact that i.e. cloudera modified this class by
     * removing static methods and made access to it via singleton pattern.
     *
     * @return the token cache
     */
    public static NMTokenCache getNMTokenCache() {
        if (nmTokenCache == null) {
            synchronized (lock) {
                if (nmTokenCache == null) {
                    Method singletonMethod = ReflectionUtils.findMethod(NMTokenCache.class, "getSingleton");
                    if (singletonMethod != null) {
                        if (log.isDebugEnabled()) {
                            log.debug("Creating NMTokenCache using NMTokenCache.getSingleton()");
                        }
                        nmTokenCache = (NMTokenCache) ReflectionUtils.invokeMethod(singletonMethod, null);
                    } else {
                        log.debug(
                                "Creating NMTokenCache using constructor, further access via instance static methods.");
                        nmTokenCache = new NMTokenCache();
                    }
                }
            }
        }
        return nmTokenCache;
    }

    public static boolean containsToken(NMTokenCache nmTokenCache, String nodeId) {
        if (nmTokenCache != null) {
            Method method = ReflectionUtils.findMethod(NMTokenCache.class, "containsNMToken", String.class);
            if (method == null) {
                method = ReflectionUtils.findMethod(NMTokenCache.class, "containsToken", String.class);
            }
            if (method != null) {
                boolean results = (Boolean) ReflectionUtils.invokeMethod(method, nmTokenCache, nodeId);
                log.debug("NMTokenCache method " + method.getName() + " returned " + results);
                return results;
            } else {
                log.debug("Unable to determine the name for 'containsToken' method on NMTokenCache class");
            }
        }
        return false;
    }
}