io.fluo.core.impl.VisibilityCache.java Source code

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Here is the source code for io.fluo.core.impl.VisibilityCache.java

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/*
 * Copyright 2014 Fluo authors (see 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 io.fluo.core.impl;

import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.Weigher;
import io.fluo.api.data.Bytes;
import io.fluo.api.data.Column;
import io.fluo.core.util.ByteUtil;
import org.apache.accumulo.core.security.ColumnVisibility;

/**
 * PArsing Column visibilities can be expensive. This class provides a cache of parsed visibility objects.
 */

public class VisibilityCache {

    public static final ColumnVisibility EMPTY_VIS = new ColumnVisibility();

    private static class VisWeigher implements Weigher<Bytes, ColumnVisibility> {
        @Override
        public int weigh(Bytes key, ColumnVisibility vis) {
            return key.length() + vis.getExpression().length + 32;
        }
    }

    private final Cache<Bytes, ColumnVisibility> visCache;

    VisibilityCache() {
        visCache = CacheBuilder.newBuilder().expireAfterAccess(TxInfoCache.CACHE_TIMEOUT_MIN, TimeUnit.MINUTES)
                .maximumWeight(10000000).weigher(new VisWeigher()).concurrencyLevel(10).build();
    }

    public ColumnVisibility getCV(Column col) {
        return getCV(col.getVisibility());
    }

    public ColumnVisibility getCV(final Bytes colvis) {
        if (colvis.length() == 0)
            return EMPTY_VIS;

        try {
            return visCache.get(colvis, new Callable<ColumnVisibility>() {
                @Override
                public ColumnVisibility call() throws Exception {
                    return new ColumnVisibility(ByteUtil.toText(colvis));
                }
            });
        } catch (ExecutionException e) {
            throw new RuntimeException(e);
        }
    }

    public void validate(Column col) {
        getCV(col.getVisibility());
    }

    public void validate(Set<Column> columns) {
        for (Column column : columns) {
            validate(column);
        }

    }

}