com.github.jcustenborder.kafka.connect.cdc.CachingTableMetadataProvider.java Source code

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Here is the source code for com.github.jcustenborder.kafka.connect.cdc.CachingTableMetadataProvider.java

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/**
 * Copyright  2017 Jeremy Custenborder (jcustenborder@gmail.com)
 *
 * 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 com.github.jcustenborder.kafka.connect.cdc;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import org.apache.kafka.connect.errors.DataException;
import org.apache.kafka.connect.storage.OffsetStorageReader;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

public abstract class CachingTableMetadataProvider<T extends PooledCDCSourceConnectorConfig>
        implements TableMetadataProvider {
    protected final T config;
    protected final OffsetStorageReader offsetStorageReader;
    final Cache<ChangeKey, TableMetadata> tableMetadataCache;
    protected Map<ChangeKey, Map<String, Object>> cachedOffsets = new HashMap<>();

    public CachingTableMetadataProvider(T config, OffsetStorageReader offsetStorageReader) {
        this.config = config;
        this.tableMetadataCache = CacheBuilder.newBuilder()
                .expireAfterWrite(config.schemaCacheMs, TimeUnit.MILLISECONDS).build();
        this.offsetStorageReader = offsetStorageReader;
    }

    @Override
    public void cacheOffset(ChangeKey changeKey, Map<String, Object> offset) {
        cachedOffsets.put(changeKey, offset);
    }

    protected abstract TableMetadata fetchTableMetadata(ChangeKey changeKey) throws SQLException;

    @Override
    public TableMetadata tableMetadata(ChangeKey changeKey) {
        try {
            return this.tableMetadataCache.get(changeKey, new Callable<TableMetadata>() {
                @Override
                public TableMetadata call() throws Exception {
                    return fetchTableMetadata(changeKey);
                }
            });

        } catch (ExecutionException ex) {
            throw new DataException("Exception thrown while getting metadata for " + changeKey, ex);
        }
    }
}