org.apache.drill.exec.server.options.FallbackOptionManager.java Source code

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Here is the source code for org.apache.drill.exec.server.options.FallbackOptionManager.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 org.apache.drill.exec.server.options;

import java.util.Iterator;

import org.apache.drill.exec.server.options.OptionValue.OptionType;
import org.apache.calcite.sql.SqlLiteral;

import com.google.common.collect.Iterables;

public abstract class FallbackOptionManager extends BaseOptionManager {
    //  private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(FallbackOptionManager.class);

    protected final OptionManager fallback;

    public FallbackOptionManager(OptionManager fallback) {
        this.fallback = fallback;
    }

    @Override
    public Iterator<OptionValue> iterator() {
        return Iterables.concat(fallback, optionIterable()).iterator();
    }

    @Override
    public OptionValue getOption(String name) {
        final OptionValue opt = getLocalOption(name);
        if (opt == null && fallback != null) {
            return fallback.getOption(name);
        } else {
            return opt;
        }
    }

    abstract Iterable<OptionValue> optionIterable();

    abstract OptionValue getLocalOption(String name);

    abstract boolean setLocalOption(OptionValue value);

    @Override
    public void setOption(OptionValue value) {
        fallback.getAdmin().validate(value);
        setValidatedOption(value);
    }

    @Override
    public void setOption(String name, SqlLiteral literal, OptionType optionType) {
        final OptionValue val = getAdmin().validate(name, literal, optionType);
        setValidatedOption(val);
    }

    private void setValidatedOption(OptionValue value) {
        if (!setLocalOption(value)) {
            fallback.setOption(value);
        }
    }

    @Override
    public OptionValue getDefault(final String name) {
        return fallback.getDefault(name);
    }

    @Override
    public OptionAdmin getAdmin() {
        return fallback.getAdmin();
    }

    @Override
    public OptionManager getSystemManager() {
        return fallback.getSystemManager();
    }

    @Override
    public OptionList getOptionList() {
        final OptionList list = new OptionList();
        for (OptionValue o : optionIterable()) {
            list.add(o);
        }
        return list;
    }
}