content: /*
   * 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.beam.sdk.extensions.sql.meta.provider.datacatalog;
  
  import com.google.cloud.datacatalog.v1beta1.Entry;
  import java.net.URI;
  import java.util.Optional;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import org.apache.beam.sdk.extensions.sql.TableUtils;
  import org.apache.beam.sdk.extensions.sql.meta.Table;
  
  /** {@link TableFactory} that understands Data Catalog Pubsub entries. */
  class PubsubTableFactory implements TableFactory {
  
    private static final String PUBSUB_API = "pubsub.googleapis.com";
  
    private static final Pattern PS_PATH_PATTERN =
        Pattern.compile("/projects/(?<PROJECT>[^/]+)/topics/(?<TOPIC>[^/]+)");
  
    @Override
    public Optional<Table.Builder> tableBuilder(Entry entry) {
      if (!URI.create(entry.getLinkedResource()).getAuthority().equalsIgnoreCase(PUBSUB_API)) {
        return Optional.empty();
      }
  
      return Optional.of(
          Table.builder()
              .location(getLocation(entry))
              .properties(TableUtils.emptyProperties())
              .type("pubsub")
              .comment(""));
    }
  
    private static String getLocation(Entry entry) {
      URI entryName = URI.create(entry.getLinkedResource());
      String psPath = entryName.getPath();
  
      Matcher bqPathMatcher = PS_PATH_PATTERN.matcher(psPath);
      if (!bqPathMatcher.matches()) {
        throw new IllegalArgumentException(
            "Unsupported format for Pubsub topic: '" + entry.getLinkedResource() + "'");
      }
  
      return psPath.substring(1);
    }
  }
  