io.hops.resolvingcache.InMemoryCache.java Source code

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Here is the source code for io.hops.resolvingcache.InMemoryCache.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 io.hops.resolvingcache;

import com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.server.namenode.INode;
import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class InMemoryCache extends Cache {

    private ConcurrentLinkedHashMap<String, Integer> cache;
    private int CACHE_MAXIMUM_SIZE;

    @Override
    protected void setConfiguration(Configuration conf) throws IOException {
        CACHE_MAXIMUM_SIZE = conf.getInt(DFSConfigKeys.DFS_INMEMORY_CACHE_MAX_SIZE,
                DFSConfigKeys.DFS_INMEMORY_CACHE_MAX_SIZE_DEFAULT);
        super.setConfiguration(conf);
    }

    @Override
    protected void startInternal() throws IOException {
        cache = new ConcurrentLinkedHashMap.Builder().maximumWeightedCapacity(CACHE_MAXIMUM_SIZE).build();
    }

    @Override
    protected void stopInternal() {
    }

    @Override
    protected void setInternal(String path, List<INode> inodes) {
        for (INode iNode : inodes) {
            cache.put(iNode.nameParentKey(), iNode.getId());
        }
    }

    @Override
    protected int[] getInternal(String path) throws IOException {
        String[] pathComponents = INode.getPathNames(path);
        int[] inodeIds = new int[pathComponents.length];
        int parentId = INodeDirectory.ROOT_PARENT_ID;
        int index = 0;
        while (index < pathComponents.length) {
            String cmp = pathComponents[index];
            Integer inodeId = cache.get(INode.nameParentKey(parentId, cmp));
            if (inodeId != null) {
                parentId = inodeId;
                inodeIds[index] = inodeId;
            } else {
                break;
            }
            index++;
        }

        //only the root was found
        if (index <= 1)
            return null;

        return Arrays.copyOf(inodeIds, index);
    }

    @Override
    protected void setInternal(INode inode) {
        throw new UnsupportedOperationException();
    }

    @Override
    protected void deleteInternal(String path) {
        throw new UnsupportedOperationException();
    }

    @Override
    protected void deleteInternal(INode inode) {
        cache.remove(inode.nameParentKey());
    }

    @Override
    protected void flushInternal() {
        cache.clear();
    }

    @Override
    protected int getRoundTrips(String path) {
        return INode.getPathNames(path).length;
    }

    @Override
    protected int getRoundTrips(List<INode> inodes) {
        return inodes.size();
    }

}