From b2b9708445bf8b67def72383a63da3285c026339 Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?=
 <bombe@pterodactylus.net>
Date: Tue, 31 Jul 2012 07:01:17 +0200
Subject: [PATCH] Add method that loads properties of several objects at once.

---
 .../demoscenemusic/data/DataManager.java           | 50 ++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/src/main/java/net/pterodactylus/demoscenemusic/data/DataManager.java b/src/main/java/net/pterodactylus/demoscenemusic/data/DataManager.java
index f06a48b..5972bd8 100644
--- a/src/main/java/net/pterodactylus/demoscenemusic/data/DataManager.java
+++ b/src/main/java/net/pterodactylus/demoscenemusic/data/DataManager.java
@@ -21,10 +21,12 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Collection;
 import java.util.EnumMap;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.Callable;
 
@@ -37,6 +39,7 @@ import net.pterodactylus.util.database.Join;
 import net.pterodactylus.util.database.Join.JoinType;
 import net.pterodactylus.util.database.ObjectCreator;
 import net.pterodactylus.util.database.ObjectCreator.StringCreator;
+import net.pterodactylus.util.database.OrWhereClause;
 import net.pterodactylus.util.database.OrderField;
 import net.pterodactylus.util.database.Parameter.IntegerParameter;
 import net.pterodactylus.util.database.Parameter.StringParameter;
@@ -950,6 +953,53 @@ public class DataManager {
 	}
 
 	/**
+	 * Loads the properties for the given objects.
+	 *
+	 * @param <T>
+	 *            The type of the object
+	 * @param objects
+	 *            The objects
+	 * @param table
+	 *            The table to load the properties from
+	 * @param type
+	 *            The type of the object (“ARTIST,” “TRACK,” etc.)
+	 * @return The object with its properties loaded
+	 * @throws DatabaseException
+	 *             if a database error occurs
+	 */
+	private <T extends Base> List<T> loadProperties(List<T> objects, final String table, final String type) throws DatabaseException {
+		final Map<String, T> objectMap = new HashMap<String, T>();
+		final Set<String> firstObjects = new HashSet<String>();
+		for (T object : objects) {
+			objectMap.put(object.getId(), object);
+			firstObjects.add(object.getId());
+		}
+		Query query = new Query(Type.SELECT, table);
+		query.addField(new Field(table + "." + type));
+		query.addField(new Field(table + ".PROPERTY"));
+		query.addField(new Field(table + ".VALUE"));
+		OrWhereClause whereClause = new OrWhereClause();
+		for (T object : objects) {
+			whereClause.add(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
+		}
+		query.addWhereClause(whereClause);
+		database.process(query, new ResultProcessor() {
+
+			@Override
+			public void processResult(ResultSet resultSet) throws SQLException {
+				String id = resultSet.getString(table + "." + type);
+				T object = objectMap.get(id);
+				if (firstObjects.remove(id)) {
+					object.getProperties().removeAll();
+				}
+				object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
+			}
+
+		});
+		return objects;
+	}
+
+	/**
 	 * {@link Artist} implementation that retrieves some attributes (such as
 	 * {@link #getGroups()}, and {@link #getTracks()}) from the
 	 * {@link DataManager} on demand.
-- 
2.7.4