org.heigit.ohsome.oshdb.api.db.OSHDBDatabase Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of oshdb-api Show documentation

API to query the OpenStreetMap History Database. Includes MapReduce functionality to filter, analyze and aggregate data.

The newest version!

package org.heigit.ohsome.oshdb.api.db;

import java.util.OptionalLong;
import org.heigit.ohsome.oshdb.api.mapreducer.MapReducer;
import org.heigit.ohsome.oshdb.util.exceptions.OSHDBTimeoutException;
import org.heigit.ohsome.oshdb.util.mappable.OSHDBMapReducible;
import org.heigit.ohsome.oshdb.util.tagtranslator.TagTranslator;

/**
 * OSHDB database backend connector.
 */
public abstract class OSHDBDatabase implements AutoCloseable {

  protected final String prefix;
  private Long timeout = null;

  protected OSHDBDatabase(String prefix) {
    this.prefix = prefix;
  }

  public abstract TagTranslator getTagTranslator();

  /**
   * Factory function that creates a mapReducer object of the appropriate data type class for this
   * oshdb backend implemenation.
   *
   * @param forClass the data type class to iterate over in the `mapping` function of the generated
   *                 MapReducer
   * @return a new mapReducer object operating on the given OSHDB backend
   */
  public abstract  MapReducer createMapReducer(Class forClass);

  /**
   * Returns metadata about the given OSHDB.
   *
   * For example copyright information, currentness of the data, spatial extent, etc.
   */
  public abstract String metadata(String property);

  /**
   * Returns the currently set db "table/cache" name prefix.
   */
  public String prefix() {
    return this.prefix;
  }

  /**
   * Set a timeout for queries on this oshdb backend.
   *
   * If a query takes longer than the given time limit, a {@link OSHDBTimeoutException} will be
   * thrown.
   *
   * @param seconds time (in seconds) a query is allowed to run for.
   * @return the current oshdb object
   */
  public OSHDBDatabase timeout(double seconds) {
    return this.timeoutInMilliseconds((long) Math.ceil(seconds * 1000));
  }

  /**
   * Clears a previously set timeout for queries on this oshdb backend.
   *
   * @return the current oshdb object
   */
  public OSHDBDatabase clearTimeout() {
    this.timeout = null;
    return this;
  }

  /**
   * Set a timeout for queries on this oshdb backend.
   *
   * If a query takes longer than the given time limit, a {@link OSHDBTimeoutException} will be
   * thrown.
   *
   * @param milliSeconds time (in milliseconds) a query is allowed to run for.
   * @return the current oshdb object
   */
  public OSHDBDatabase timeoutInMilliseconds(long milliSeconds) {
    this.timeout = milliSeconds;
    return this;
  }

  /**
   * Gets the timeout for queries on this oshdb backend, if present.
   *
   * @return the currently set query timeout in milliseconds
   */
  public OptionalLong timeoutInMilliseconds() {
    if (this.timeout == null) {
      return OptionalLong.empty();
    } else {
      return OptionalLong.of(this.timeout);
    }
  }
}