alluxio.SetAndRestoreConfiguration.java Source code

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Here is the source code for alluxio.SetAndRestoreConfiguration.java

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/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio;

import com.google.common.collect.ImmutableMap;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * An AutoCloseable which temporarily modifies configuration when it is constructed and
 * restores the property when it is closed.
 */
public final class SetAndRestoreConfiguration implements AutoCloseable {
    private final Map<PropertyKey, String> mOriginalValues = new HashMap<>();
    private final Set<PropertyKey> mOriginalNullKeys = new HashSet<>();

    /**
     * @param key the key of the configuration property to set
     * @param value the value to set it to
     */
    public SetAndRestoreConfiguration(PropertyKey key, String value) {
        this(ImmutableMap.of(key, value));
    }

    /**
     * @param keyValuePairs the key value pairs of the configuration property to set
     */
    public SetAndRestoreConfiguration(Map<PropertyKey, String> keyValuePairs) {
        for (Map.Entry<PropertyKey, String> entry : keyValuePairs.entrySet()) {
            PropertyKey key = entry.getKey();
            String value = entry.getValue();
            if (Configuration.containsKey(key)) {
                mOriginalValues.put(key, Configuration.get(key));
            } else {
                mOriginalNullKeys.add(key);
            }
            Configuration.set(key, value);
        }
    }

    @Override
    public void close() throws Exception {
        for (Map.Entry<PropertyKey, String> entry : mOriginalValues.entrySet()) {
            Configuration.set(entry.getKey(), entry.getValue());
        }
        for (PropertyKey key : mOriginalNullKeys) {
            Configuration.unset(key);
        }
    }
}