org.apache.tajo.storage.fragment.FragmentConvertor.java Source code

Introduction

Here is the source code for org.apache.tajo.storage.fragment.FragmentConvertor.java

Source

/**
 * 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.tajo.storage.fragment;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.protobuf.ByteString;
import org.apache.hadoop.conf.Configuration;
import org.apache.tajo.annotation.ThreadSafe;

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.List;
import java.util.Map;

import static org.apache.tajo.catalog.proto.CatalogProtos.FragmentProto;

@ThreadSafe
public class FragmentConvertor {
    /**
     * Cache of fragment classes
     */
    protected static final Map<String, Class<? extends Fragment>> CACHED_FRAGMENT_CLASSES = Maps.newConcurrentMap();
    /**
     * Cache of constructors for each class.
     */
    private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE = Maps.newConcurrentMap();
    /**
     * default parameter for all constructors
     */
    private static final Class<?>[] DEFAULT_FRAGMENT_PARAMS = { ByteString.class };

    public static Class<? extends Fragment> getFragmentClass(Configuration conf, String storeType)
            throws IOException {
        Class<? extends Fragment> fragmentClass = CACHED_FRAGMENT_CLASSES.get(storeType.toLowerCase());
        if (fragmentClass == null) {
            fragmentClass = conf.getClass(String.format("tajo.storage.fragment.%s.class", storeType.toLowerCase()),
                    null, Fragment.class);
            CACHED_FRAGMENT_CLASSES.put(storeType.toLowerCase(), fragmentClass);
        }

        if (fragmentClass == null) {
            throw new IOException("No such a fragment for " + storeType.toLowerCase());
        }

        return fragmentClass;
    }

    public static <T extends Fragment> T convert(Class<T> clazz, FragmentProto fragment) {
        T result;
        try {
            Constructor<T> constructor = (Constructor<T>) CONSTRUCTOR_CACHE.get(clazz);
            if (constructor == null) {
                constructor = clazz.getDeclaredConstructor(DEFAULT_FRAGMENT_PARAMS);
                constructor.setAccessible(true);
                CONSTRUCTOR_CACHE.put(clazz, constructor);
            }
            result = constructor.newInstance(new Object[] { fragment.getContents() });
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        return result;
    }

    public static <T extends Fragment> T convert(Configuration conf, FragmentProto fragment) throws IOException {
        Class<T> fragmentClass = (Class<T>) getFragmentClass(conf, fragment.getStoreType().toLowerCase());
        if (fragmentClass == null) {
            throw new IOException("No such a fragment class for " + fragment.getStoreType());
        }
        return convert(fragmentClass, fragment);
    }

    public static <T extends Fragment> List<T> convert(Class<T> clazz, FragmentProto... fragments)
            throws IOException {
        List<T> list = Lists.newArrayList();
        if (fragments == null) {
            return list;
        }
        for (FragmentProto proto : fragments) {
            list.add(convert(clazz, proto));
        }
        return list;
    }

    public static <T extends Fragment> List<T> convert(Configuration conf, FragmentProto... fragments)
            throws IOException {
        List<T> list = Lists.newArrayList();
        if (fragments == null) {
            return list;
        }
        for (FragmentProto proto : fragments) {
            list.add((T) convert(conf, proto));
        }
        return list;
    }

    public static List<FragmentProto> toFragmentProtoList(Fragment... fragments) {
        List<FragmentProto> list = Lists.newArrayList();
        if (fragments == null) {
            return list;
        }
        for (Fragment fragment : fragments) {
            list.add(fragment.getProto());
        }
        return list;
    }

    public static FragmentProto[] toFragmentProtoArray(Fragment... fragments) {
        List<FragmentProto> list = toFragmentProtoList(fragments);
        return list.toArray(new FragmentProto[list.size()]);
    }
}