Return-Path: Delivered-To: apmail-lucene-mahout-commits-archive@minotaur.apache.org Received: (qmail 86318 invoked from network); 13 Jul 2009 09:45:01 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 13 Jul 2009 09:45:01 -0000 Received: (qmail 2635 invoked by uid 500); 13 Jul 2009 09:45:11 -0000 Delivered-To: apmail-lucene-mahout-commits-archive@lucene.apache.org Received: (qmail 2590 invoked by uid 500); 13 Jul 2009 09:45:10 -0000 Mailing-List: contact mahout-commits-help@lucene.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: mahout-dev@lucene.apache.org Delivered-To: mailing list mahout-commits@lucene.apache.org Received: (qmail 2581 invoked by uid 99); 13 Jul 2009 09:45:10 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 13 Jul 2009 09:45:10 +0000 X-ASF-Spam-Status: No, hits=-2000.0 required=10.0 tests=ALL_TRUSTED X-Spam-Check-By: apache.org Received: from [140.211.11.4] (HELO eris.apache.org) (140.211.11.4) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 13 Jul 2009 09:45:06 +0000 Received: by eris.apache.org (Postfix, from userid 65534) id A19742388878; Mon, 13 Jul 2009 09:44:45 +0000 (UTC) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: svn commit: r793519 - in /lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl: common/jdbc/ model/jdbc/ recommender/slopeone/jdbc/ similarity/jdbc/ Date: Mon, 13 Jul 2009 09:44:45 -0000 To: mahout-commits@lucene.apache.org From: srowen@apache.org X-Mailer: svnmailer-1.0.8 Message-Id: <20090713094445.A19742388878@eris.apache.org> X-Virus-Checked: Checked by ClamAV on apache.org Author: srowen Date: Mon Jul 13 09:44:44 2009 New Revision: 793519 URL: http://svn.apache.org/viewvc?rev=793519&view=rev Log: Initial cut at MySQLJDBCItemSimilarity Added: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/common/jdbc/ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/common/jdbc/AbstractJDBCComponent.java lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/AbstractJDBCItemSimilarity.java lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/MySQLJDBCItemSimilarity.java Modified: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/AbstractJDBCDataModel.java lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/MySQLJDBCDataModel.java lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/jdbc/AbstractJDBCDiffStorage.java Added: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/common/jdbc/AbstractJDBCComponent.java URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/common/jdbc/AbstractJDBCComponent.java?rev=793519&view=auto ============================================================================== --- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/common/jdbc/AbstractJDBCComponent.java (added) +++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/common/jdbc/AbstractJDBCComponent.java Mon Jul 13 09:44:44 2009 @@ -0,0 +1,92 @@ +/** + * 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.mahout.cf.taste.impl.common.jdbc; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import org.apache.mahout.cf.taste.common.TasteException; + +import javax.sql.DataSource; +import javax.naming.Context; +import javax.naming.InitialContext; +import javax.naming.NamingException; +import java.sql.ResultSet; +import java.sql.SQLException; + +/** + * A helper class with common elements for several JDBC-related components. + */ +public abstract class AbstractJDBCComponent { + + private static final Logger log = LoggerFactory.getLogger(AbstractJDBCComponent.class); + + public static final String DEFAULT_DATASOURCE_NAME = "jdbc/taste"; + private static final int DEFAULT_FETCH_SIZE = 1000; // A max, "big" number of rows to buffer at once + + protected static void checkNotNullAndLog(String argName, Object value) { + if (value == null || value.toString().length() == 0) { + throw new IllegalArgumentException(argName + " is null or empty"); + } + log.debug("{}: {}", argName, value); + } + + protected static void checkNotNullAndLog(String argName, Object[] values) { + if (values == null || values.length == 0) { + throw new IllegalArgumentException(argName + " is null or zero-length"); + } + for (Object value : values) { + checkNotNullAndLog(argName, value); + } + } + + + /** + *

Looks up a {@link DataSource} by name from JNDI. "java:comp/env/" is prepended to the argument before looking up + * the name in JNDI.

+ * + * @param dataSourceName JNDI name where a {@link DataSource} is bound (e.g. "jdbc/taste") + * @return {@link DataSource} under that JNDI name + * @throws TasteException if a JNDI error occurs + */ + public static DataSource lookupDataSource(String dataSourceName) throws TasteException { + Context context = null; + try { + context = new InitialContext(); + return (DataSource) context.lookup("java:comp/env/" + dataSourceName); + } catch (NamingException ne) { + throw new TasteException(ne); + } finally { + if (context != null) { + try { + context.close(); + } catch (NamingException ne) { + log.warn("Error while closing Context; continuing...", ne); + } + } + } + } + + protected int getFetchSize() { + return DEFAULT_FETCH_SIZE; + } + + protected void advanceResultSet(ResultSet resultSet, int n) throws SQLException { + resultSet.relative(n); + } + +} Modified: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/AbstractJDBCDataModel.java URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/AbstractJDBCDataModel.java?rev=793519&r1=793518&r2=793519&view=diff ============================================================================== --- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/AbstractJDBCDataModel.java (original) +++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/AbstractJDBCDataModel.java Mon Jul 13 09:44:44 2009 @@ -25,6 +25,7 @@ import org.apache.mahout.cf.taste.impl.common.IteratorIterable; import org.apache.mahout.cf.taste.impl.common.Retriever; import org.apache.mahout.cf.taste.impl.common.SkippingIterator; +import org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent; import org.apache.mahout.cf.taste.impl.model.GenericItem; import org.apache.mahout.cf.taste.impl.model.GenericPreference; import org.apache.mahout.cf.taste.impl.model.GenericUser; @@ -70,18 +71,15 @@ * code, you will run into subtle problems because the {@link Long} values won't be equal to or compare correctly to the * underlying {@link String} key values.

*/ -public abstract class AbstractJDBCDataModel implements JDBCDataModel { +public abstract class AbstractJDBCDataModel extends AbstractJDBCComponent implements JDBCDataModel { static final Logger log = LoggerFactory.getLogger(AbstractJDBCDataModel.class); - public static final String DEFAULT_DATASOURCE_NAME = "jdbc/taste"; public static final String DEFAULT_PREFERENCE_TABLE = "taste_preferences"; public static final String DEFAULT_USER_ID_COLUMN = "user_id"; public static final String DEFAULT_ITEM_ID_COLUMN = "item_id"; public static final String DEFAULT_PREFERENCE_COLUMN = "preference"; - static final int DEFAULT_FETCH_SIZE = 1000; // A max, "big" number of rows to buffer at once - private final DataSource dataSource; private final String preferenceTable; private final String userIDColumn; @@ -198,39 +196,6 @@ } - private static void checkNotNullAndLog(String argName, Object value) { - if (value == null || value.toString().length() == 0) { - throw new IllegalArgumentException(argName + " is null or empty"); - } - log.debug("{}: {}", argName, value); - } - - /** - *

Looks up a {@link DataSource} by name from JNDI. "java:comp/env/" is prepended to the argument before looking up - * the name in JNDI.

- * - * @param dataSourceName JNDI name where a {@link DataSource} is bound (e.g. "jdbc/taste") - * @return {@link DataSource} under that JNDI name - * @throws TasteException if a JNDI error occurs - */ - public static DataSource lookupDataSource(String dataSourceName) throws TasteException { - Context context = null; - try { - context = new InitialContext(); - return (DataSource) context.lookup("java:comp/env/" + dataSourceName); - } catch (NamingException ne) { - throw new TasteException(ne); - } finally { - if (context != null) { - try { - context.close(); - } catch (NamingException ne) { - log.warn("Error while closing Context; continuing...", ne); - } - } - } - } - /** @return the {@link DataSource} that this instance is using */ @Override public DataSource getDataSource() { @@ -253,14 +218,6 @@ return preferenceColumn; } - protected int getFetchSize() { - return DEFAULT_FETCH_SIZE; - } - - protected void advanceResultSet(ResultSet resultSet, int n) throws SQLException { - resultSet.relative(n); - } - @Override public Iterable getUsers() throws TasteException { log.debug("Retrieving all users..."); Modified: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/MySQLJDBCDataModel.java URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/MySQLJDBCDataModel.java?rev=793519&r1=793518&r2=793519&view=diff ============================================================================== --- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/MySQLJDBCDataModel.java (original) +++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/jdbc/MySQLJDBCDataModel.java Mon Jul 13 09:44:44 2009 @@ -29,12 +29,15 @@ * default, this class assumes that there is a {@link DataSource} available under the JNDI name "jdbc/taste", which * gives access to a database with a "taste_preferences" table with the following schema:

* - * - * - *
user_iditem_idpreference
ABC1230.9
ABC4560.1
DEF1230.2
DEF7890.3
+ * + * + * + * + * + * + *
user_iditem_idpreference
ABC1230.9
ABC4560.1
DEF1230.2
DEF7890.3
* - *

user_id must have a type compatible with the Java String type. item_id must - * have a type compatible with the Java String type. preference must have a type compatible + *

preference must have a type compatible * with the Java double type. For example, the following command sets up a suitable table in MySQL, * complete with primary key and indexes:

* Modified: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/jdbc/AbstractJDBCDiffStorage.java URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/jdbc/AbstractJDBCDiffStorage.java?rev=793519&r1=793518&r2=793519&view=diff ============================================================================== --- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/jdbc/AbstractJDBCDiffStorage.java (original) +++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/jdbc/AbstractJDBCDiffStorage.java Mon Jul 13 09:44:44 2009 @@ -23,6 +23,7 @@ import org.apache.mahout.cf.taste.impl.common.IOUtils; import org.apache.mahout.cf.taste.impl.common.RefreshHelper; import org.apache.mahout.cf.taste.impl.common.RunningAverage; +import org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent; import org.apache.mahout.cf.taste.model.Item; import org.apache.mahout.cf.taste.model.JDBCDataModel; import org.apache.mahout.cf.taste.model.Preference; @@ -46,12 +47,10 @@ * org.apache.mahout.cf.taste.model.DataModel} used; it needs a {@link JDBCDataModel} attached to the same database * since its efficent operation depends on accessing preference data in the database directly.

*/ -public abstract class AbstractJDBCDiffStorage implements DiffStorage { +public abstract class AbstractJDBCDiffStorage extends AbstractJDBCComponent implements DiffStorage { private static final Logger log = LoggerFactory.getLogger(AbstractJDBCDiffStorage.class); - static final int DEFAULT_FETCH_SIZE = 1000; // A max, "big" number of rows to buffer at once - public static final String DEFAULT_DIFF_TABLE = "taste_slopeone_diffs"; public static final String DEFAULT_ITEM_A_COLUMN = "item_id_a"; public static final String DEFAULT_ITEM_B_COLUMN = "item_id_b"; @@ -83,9 +82,18 @@ String createDiffsSQL, String diffsExistSQL, int minDiffCount) throws TasteException { - if (dataModel == null) { - throw new IllegalArgumentException("dataModel is null"); - } + + checkNotNullAndLog("dataModel", dataModel); + checkNotNullAndLog("getDiffSQL", getDiffSQL); + checkNotNullAndLog("getDiffsSQL", getDiffsSQL); + checkNotNullAndLog("getAverageItemPrefSQL", getAverageItemPrefSQL); + checkNotNullAndLog("updateDiffSQLs", updateDiffSQLs); + checkNotNullAndLog("removeDiffSQLs", removeDiffSQLs); + checkNotNullAndLog("getRecommendableItemsSQL", getRecommendableItemsSQL); + checkNotNullAndLog("deleteDiffsSQL", deleteDiffsSQL); + checkNotNullAndLog("createDiffsSQL", createDiffsSQL); + checkNotNullAndLog("diffsExistSQL", diffsExistSQL); + if (minDiffCount < 0) { throw new IllegalArgumentException("minDiffCount is not positive"); } @@ -117,10 +125,6 @@ } } - protected int getFetchSize() { - return DEFAULT_FETCH_SIZE; - } - @Override public RunningAverage getDiff(Object itemID1, Object itemID2) throws TasteException { Connection conn = null; Added: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/AbstractJDBCItemSimilarity.java URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/AbstractJDBCItemSimilarity.java?rev=793519&view=auto ============================================================================== --- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/AbstractJDBCItemSimilarity.java (added) +++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/AbstractJDBCItemSimilarity.java Mon Jul 13 09:44:44 2009 @@ -0,0 +1,149 @@ +/** + * 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.mahout.cf.taste.impl.similarity.jdbc; + +import org.apache.mahout.cf.taste.similarity.ItemSimilarity; +import org.apache.mahout.cf.taste.model.Item; +import org.apache.mahout.cf.taste.common.TasteException; +import org.apache.mahout.cf.taste.common.Refreshable; +import org.apache.mahout.cf.taste.common.NoSuchItemException; +import org.apache.mahout.cf.taste.impl.common.IOUtils; +import org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent; +import org.apache.mahout.cf.taste.impl.model.jdbc.ConnectionPoolDataSource; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.sql.DataSource; +import java.util.Collection; +import java.sql.Connection; +import java.sql.PreparedStatement; +import java.sql.ResultSet; +import java.sql.SQLException; + +/** + * An {@link ItemSimilarity} which draws pre-computed item-item similarities from + * a database table via JDBC. + */ +public abstract class AbstractJDBCItemSimilarity extends AbstractJDBCComponent implements ItemSimilarity { + + private static final Logger log = LoggerFactory.getLogger(AbstractJDBCItemSimilarity.class); + + static final String DEFAULT_SIMILARITY_TABLE = "taste_item_similarity"; + static final String DEFAULT_ITEM_A_ID_COLUMN = "item_id_a"; + static final String DEFAULT_ITEM_B_ID_COLUMN = "item_id_b"; + static final String DEFAULT_SIMILARITY_COLUMN = "similarity"; + + private final DataSource dataSource; + private final String similarityTable; + private final String itemAIDColumn; + private final String itemBIDColumn; + private final String similarityColumn; + private final String getItemItemSimilaritySQL; + + protected AbstractJDBCItemSimilarity(DataSource dataSource, + String getItemItemSimilaritySQL) { + this(dataSource, + DEFAULT_SIMILARITY_TABLE, + DEFAULT_ITEM_A_ID_COLUMN, + DEFAULT_ITEM_B_ID_COLUMN, + DEFAULT_SIMILARITY_COLUMN, + getItemItemSimilaritySQL); + } + + protected AbstractJDBCItemSimilarity(DataSource dataSource, + String similarityTable, + String itemAIDColumn, + String itemBIDColumn, + String similarityColumn, + String getItemItemSimilaritySQL) { + + log.debug("Creating AbstractJDBCItemSimilarity..."); + + checkNotNullAndLog("similarityTable", similarityTable); + checkNotNullAndLog("itemAIDColumn", itemAIDColumn); + checkNotNullAndLog("itemBIDColumn", itemBIDColumn); + checkNotNullAndLog("similarityColumn", similarityColumn); + + checkNotNullAndLog("getItemItemSimilaritySQL", getItemItemSimilaritySQL); + + if (!(dataSource instanceof ConnectionPoolDataSource)) { + log.warn("You are not using ConnectionPoolDataSource. Make sure your DataSource pools connections " + + "to the database itself, or database performance will be severely reduced."); + } + + this.dataSource = dataSource; + this.similarityTable = similarityTable; + this.itemAIDColumn = itemAIDColumn; + this.itemBIDColumn = itemBIDColumn; + this.similarityColumn = similarityColumn; + this.getItemItemSimilaritySQL = getItemItemSimilaritySQL; + } + + protected String getSimilarityTable() { + return similarityTable; + } + + protected String getItemAIDColumn() { + return itemAIDColumn; + } + + protected String getItemBIDColumn() { + return itemBIDColumn; + } + + protected String getSimilarityColumn() { + return similarityColumn; + } + + @Override + public double itemSimilarity(Item item1, Item item2) throws TasteException { + Connection conn = null; + PreparedStatement stmt = null; + ResultSet rs = null; + + try { + conn = dataSource.getConnection(); + stmt = conn.prepareStatement(getItemItemSimilaritySQL, ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); + stmt.setFetchDirection(ResultSet.FETCH_FORWARD); + stmt.setFetchSize(getFetchSize()); + stmt.setObject(1, item1.getID()); + stmt.setObject(2, item2.getID()); + + log.debug("Executing SQL query: {}", getItemItemSimilaritySQL); + rs = stmt.executeQuery(); + + if (rs.next()) { + return rs.getDouble(1); + } else { + throw new NoSuchItemException(); + } + + } catch (SQLException sqle) { + log.warn("Exception while retrieving user", sqle); + throw new TasteException(sqle); + } finally { + IOUtils.quietClose(rs, stmt, conn); + } + } + + @Override + public void refresh(Collection alreadyRefreshed) { + // do nothing + } + +} Added: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/MySQLJDBCItemSimilarity.java URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/MySQLJDBCItemSimilarity.java?rev=793519&view=auto ============================================================================== --- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/MySQLJDBCItemSimilarity.java (added) +++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/similarity/jdbc/MySQLJDBCItemSimilarity.java Mon Jul 13 09:44:44 2009 @@ -0,0 +1,93 @@ +/** + * 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.mahout.cf.taste.impl.similarity.jdbc; + +import org.apache.mahout.cf.taste.common.TasteException; +import org.apache.mahout.cf.taste.similarity.ItemSimilarity; + +import javax.sql.DataSource; +import java.sql.ResultSet; +import java.sql.SQLException; + +/** + *

An {@link ItemSimilarity} backed by a MySQL database and accessed via JDBC. + * It may work with other JDBC databases. By default, this class assumes that there is a {@link DataSource} + * available under the JNDI name "jdbc/taste", which + * gives access to a database with a "taste_item_similarity" table with the following schema:

+ * + * + * + * + * + *
item_id_aitem_id_bsimilarity
ABCDEF0.9
DEFEFG0.1
+ * + *

For example, the following command sets up a suitable table in MySQL, + * complete with primary key and indexes:

+ * + * 
+ * CREATE TABLE taste_item_similarity (
+ *   item_id_a VARCHAR(10) NOT NULL,
+ *   item_id_b VARCHAR(10) NOT NULL,
+ *   similarity FLOAT NOT NULL,
+ *   PRIMARY KEY (item_id_a, item_id_b),
+ * )
+ *
+ * + * + * @see org.apache.mahout.cf.taste.impl.recommender.slopeone.jdbc.MySQLJDBCDiffStorage + * @see org.apache.mahout.cf.taste.impl.model.jdbc.MySQLJDBCDataModel + */ +public final class MySQLJDBCItemSimilarity extends AbstractJDBCItemSimilarity { + + public MySQLJDBCItemSimilarity() throws TasteException { + this(DEFAULT_DATASOURCE_NAME); + } + + public MySQLJDBCItemSimilarity(String dataSourceName) throws TasteException { + this(lookupDataSource(dataSourceName)); + } + + public MySQLJDBCItemSimilarity(DataSource dataSource) { + this(dataSource, + DEFAULT_SIMILARITY_TABLE, + DEFAULT_ITEM_A_ID_COLUMN, + DEFAULT_ITEM_B_ID_COLUMN, + DEFAULT_SIMILARITY_COLUMN); + } + + public MySQLJDBCItemSimilarity(DataSource dataSource, + String similarityTable, + String itemAIDColumn, + String itemBIDColumn, + String similarityColumn) { + super(dataSource, + similarityTable, + itemAIDColumn, + itemBIDColumn, + similarityColumn, + "SELECT " + similarityColumn + " FROM " + similarityTable + " WHERE " + itemAIDColumn + "=? AND " + + itemBIDColumn + "=?"); + } + + @Override + protected int getFetchSize() { + // Need to return this for MySQL Connector/J to make it use streaming mode + return Integer.MIN_VALUE; + } + +} \ No newline at end of file