Java tutorial
/** * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/agpl.html> * * Copyright (C) Ushahidi Inc. All Rights Reserved. */ package com.ushahidi.swiftriver.core.api.dao.impl; import java.sql.PreparedStatement; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import javax.sql.DataSource; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.jdbc.core.BatchPreparedStatementSetter; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.namedparam.MapSqlParameterSource; import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate; import org.springframework.stereotype.Repository; import com.ushahidi.swiftriver.core.api.dao.PlaceDao; import com.ushahidi.swiftriver.core.api.dao.SequenceDao; import com.ushahidi.swiftriver.core.model.Drop; import com.ushahidi.swiftriver.core.model.Place; import com.ushahidi.swiftriver.core.model.Sequence; import com.ushahidi.swiftriver.core.util.MD5Util; @Repository public class JpaPlaceDao extends AbstractJpaDao<Place> implements PlaceDao { @Autowired private SequenceDao sequenceDao; private NamedParameterJdbcTemplate namedJdbcTemplate; private JdbcTemplate jdbcTemplate; @Autowired public void setDataSource(DataSource dataSource) { this.namedJdbcTemplate = new NamedParameterJdbcTemplate(dataSource); this.jdbcTemplate = new JdbcTemplate(dataSource); } public Place create(Place place) { place = formatPlace(place); place.setHash(getHash(place)); return super.create(place); } /** * Generate a hash for the given place. * * @param t * @return */ public String getHash(Place p) { String hash = MD5Util.md5Hex(p.getPlaceName() + p.getLongitude().toString() + p.getLatitude().toString()); return hash; } private Place formatPlace(Place place) { place.setPlaceName(place.getPlaceName().trim()); place.setPlaceNameCanonical(place.getPlaceName().toLowerCase()); return place; } /* * (non-Javadoc) * * @see * com.ushahidi.swiftriver.core.api.dao.PlaceDao#findByHash(java.lang.String * ) */ @SuppressWarnings("unchecked") public Place findByHash(String hash) { String sql = "FROM Place WHERE hash = :hash"; List<Place> places = (List<Place>) em.createQuery(sql).setParameter("hash", hash).getResultList(); return places.isEmpty() ? null : places.get(0); } /* * (non-Javadoc) * * @see com.ushahidi.swiftriver.core.api.dao.PlaceDao#findById(long) */ public Place findById(long placeId) { return this.em.find(Place.class, placeId); } @Override public void getPlaces(List<Drop> drops) { // Get a lock Sequence seq = sequenceDao.findById("places"); Map<String, List<int[]>> newPlaceIndex = getNewPlaceIndex(drops); if (newPlaceIndex.size() > 0) { // Find places that already exist in the db updateNewPlaceIndex(newPlaceIndex, drops); // Insert new place into the db batchInsert(newPlaceIndex, drops, seq); } } /** * Generates a mapping of place hashes to list index for the given drops. * Also populates an place hash into the given list of drops. * * @param drops * @return */ private Map<String, List<int[]>> getNewPlaceIndex(List<Drop> drops) { Map<String, List<int[]>> newPlaceIndex = new HashMap<String, List<int[]>>(); // Generate hashes for each new drops i.e. those without an id for (int i = 0; i < drops.size(); i++) { Drop drop = drops.get(i); List<Place> places = drop.getPlaces(); if (places == null) continue; for (int j = 0; j < places.size(); j++) { Place place = places.get(j); // Cleanup the place place = formatPlace(place); String hash = getHash(place); place.setHash(hash); // Keep a record of where this hash is in the drop list List<int[]> indexes; if (newPlaceIndex.containsKey(hash)) { indexes = newPlaceIndex.get(hash); } else { indexes = new ArrayList<int[]>(); newPlaceIndex.put(hash, indexes); } // Location of the place in the drops array is an i,j tuple int[] loc = { i, j }; indexes.add(loc); } } return newPlaceIndex; } /** * For the given list of new drops, find those that the place hash already * exists in the db and update the drop entry with the existing id. Also * remove the hash from the new place index for those that already exist. * * @param newPlaceIndex * @param drops */ private void updateNewPlaceIndex(Map<String, List<int[]>> newPlaceIndex, List<Drop> drops) { // First find and update existing drops with their ids. String sql = "SELECT id, hash FROM places WHERE hash IN (:hashes)"; MapSqlParameterSource params = new MapSqlParameterSource(); params.addValue("hashes", newPlaceIndex.keySet()); List<Map<String, Object>> results = this.namedJdbcTemplate.queryForList(sql, params); // Update id for the drops that were found for (Map<String, Object> result : results) { String hash = (String) result.get("hash"); Long id = ((Number) result.get("id")).longValue(); List<int[]> indexes = newPlaceIndex.get(hash); for (int[] index : indexes) { drops.get(index[0]).getPlaces().get(index[1]).setId(id); } // Hash is not for a new drop so remove it newPlaceIndex.remove(hash); } } /** * Insert new places in a single batch statement * * @param newPlaceIndex * @param drops */ private void batchInsert(final Map<String, List<int[]>> newPlaceIndex, final List<Drop> drops, Sequence seq) { final List<String> hashes = new ArrayList<String>(); hashes.addAll(newPlaceIndex.keySet()); final long startKey = sequenceDao.getIds(seq, hashes.size()); String sql = "INSERT INTO places (id, hash, place_name, " + "place_name_canonical, longitude, latitude) " + "VALUES (?,?,?,?,?,?)"; jdbcTemplate.batchUpdate(sql, new BatchPreparedStatementSetter() { public void setValues(PreparedStatement ps, int i) throws SQLException { String hash = hashes.get(i); // Update drops with the newly generated id for (int[] index : newPlaceIndex.get(hash)) { drops.get(index[0]).getPlaces().get(index[1]).setId(startKey + i); } int[] index = newPlaceIndex.get(hash).get(0); Place place = drops.get(index[0]).getPlaces().get(index[1]); ps.setLong(1, place.getId()); ps.setString(2, place.getHash()); ps.setString(3, place.getPlaceName()); ps.setString(4, place.getPlaceNameCanonical()); ps.setFloat(5, place.getLongitude()); ps.setFloat(6, place.getLatitude()); } public int getBatchSize() { return hashes.size(); } }); // Update the droplet_places table insertDropletPlaces(drops); } /** * Populate the droplet places table. * * @param drops */ private void insertDropletPlaces(List<Drop> drops) { // List of drop IDs in the drops list List<Long> dropIds = new ArrayList<Long>(); // List of places in a drop Map<Long, Set<Long>> dropletPlacesMap = new HashMap<Long, Set<Long>>(); for (Drop drop : drops) { if (drop.getPlaces() == null) continue; dropIds.add(drop.getId()); for (Place place : drop.getPlaces()) { Set<Long> places = null; if (dropletPlacesMap.containsKey(drop.getId())) { places = dropletPlacesMap.get(drop.getId()); } else { places = new HashSet<Long>(); dropletPlacesMap.put(drop.getId(), places); } places.add(place.getId()); } } // Find droplet places that already exist in the db String sql = "SELECT droplet_id, place_id FROM droplets_places WHERE droplet_id in (:ids)"; MapSqlParameterSource params = new MapSqlParameterSource(); params.addValue("ids", dropIds); List<Map<String, Object>> results = this.namedJdbcTemplate.queryForList(sql, params); // Remove already existing droplet_places from our Set for (Map<String, Object> result : results) { long dropletId = ((Number) result.get("droplet_id")).longValue(); long placeId = ((Number) result.get("place_id")).longValue(); Set<Long> placeSet = dropletPlacesMap.get(dropletId); if (placeSet != null) { placeSet.remove(placeId); } } // Insert the remaining items in the set into the db sql = "INSERT INTO droplets_places (droplet_id, place_id) VALUES (?,?)"; final List<long[]> dropletPlacesList = new ArrayList<long[]>(); for (Long dropletId : dropletPlacesMap.keySet()) { for (Long placeId : dropletPlacesMap.get(dropletId)) { long[] dropletPlace = { dropletId, placeId }; dropletPlacesList.add(dropletPlace); } } jdbcTemplate.batchUpdate(sql, new BatchPreparedStatementSetter() { public void setValues(PreparedStatement ps, int i) throws SQLException { long[] dropletPlace = dropletPlacesList.get(i); ps.setLong(1, dropletPlace[0]); ps.setLong(2, dropletPlace[1]); } public int getBatchSize() { return dropletPlacesList.size(); } }); } }