1 files changed, 173 insertions, 0 deletions
diff --git a/src/connectors/src/data/io/sql/SQLRelDataReader.java b/src/connectors/src/data/io/sql/SQLRelDataReader.java
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+++ b/src/connectors/src/data/io/sql/SQLRelDataReader.java
@@ -0,0 +1,173 @@
+/*
+ * SSSync, a Simple and Stupid Synchronizer for data with multi-valued attributes
+ * Copyright (C) 2014  Ludovic Pouzenc <ludovic@pouzenc.fr>
+ *  
+ * This file is part of SSSync.
+ *
+ *  SSSync is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  SSSync 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with SSSync.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package data.io.sql;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Iterator;
+
+import data.MVDataEntry;
+import data.io.AbstractMVDataReader;
+
+/**
+ * Stream-oriented reader from a particular RDBMS source.
+ * 
+ * @author lpouzenc
+ */
+public class SQLRelDataReader extends AbstractMVDataReader {
+
+	private final Connection conn;
+	private final String request;
+	
+	private transient String columnNames[];
+	private transient ResultSet rs;
+	private transient boolean didNext;
+	private transient boolean hasNext;
+
+	/**
+	 * Build a new reader from an existing connection and a File containing a SELECT statement.
+	 * @param dataSourceName A short string representing this reader (for logging) 
+	 * @param conn A pre-established SQL data connection
+	 * @param queryFile An SQL file containing an SQL SELECT statement
+	 * @throws IOException 
+	 */
+	public SQLRelDataReader(String dataSourceName, Connection conn, File queryFile) throws IOException  {
+		this.dataSourceName = dataSourceName;
+		this.conn = conn;
+		this.request = readEntireFile(queryFile);
+	}
+	
+	/**
+	 * Build a new reader from an existing connection and a String containing a SELECT statement.
+	 * @param dataSourceName A short string representing this reader (for logging)
+	 * @param conn A pre-established SQL data connection
+	 * @param query A String containing an SQL SELECT statement
+	 * @throws IOException 
+	 */
+	public SQLRelDataReader(String dataSourceName, Connection conn, String query) {
+		this.dataSourceName = dataSourceName;
+		this.conn = conn;
+		this.request = query;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 * Note : multiple iterators on the same instance are not supported
+	 */
+	@Override
+	public Iterator<MVDataEntry> iterator() {
+		try {
+			// Reset iterator-related attributes
+			hasNext = false;
+			didNext = false;
+			
+			// Close and free any previous request result
+			if ( rs != null ) {
+				rs.close();
+			}
+			// (Re-)Execute the SQL request
+			Statement stmt = conn.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
+			rs = stmt.executeQuery(request);
+			
+			// Get the column names
+			ResultSetMetaData rsmd = rs.getMetaData();
+			columnNames = new String[rsmd.getColumnCount()];
+			for (int i = 0; i < columnNames.length ; i++) {
+				// Java SQL : all indices starts at 1 (it sucks !)
+				columnNames[i] = rsmd.getColumnName(i+1); 
+			}
+		} catch (SQLException e) {
+			throw new RuntimeException("Could not execute query : " + e.getMessage() + "\n" + request );
+		}
+		
+		return this;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public boolean hasNext() {
+		// java.sql.ResultSet don't implement Iterable interface at all
+		// It's next() don't return anything except hasNext() result but it moves the cursor !  
+        if (!didNext) {
+            try {
+				hasNext = rs.next();
+			} catch (SQLException e) {
+				throw new RuntimeException(e);
+			}
+            didNext = true;
+        }
+        return hasNext;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public MVDataEntry next() {
+		MVDataEntry result = null;
+		try {
+	        if (!didNext) {
+	            rs.next();
+	        }
+	        didNext = false;
+	        //TODO Instead of always use the first col, user could choose a specific columnName like in LDAP
+			String key = rs.getString(1); 
+			result = new MVDataEntry(key);
+			for (int i = 0; i < columnNames.length ; i++) {
+				// Java SQL : all indices starts at 1 (it sucks !)
+				result.splitAndPut(columnNames[i], rs.getString(i+1), ";"); // TODO regex should be an option
+			}
+			
+		} catch (SQLException e) {
+			throw new RuntimeException("Exception while reading next line in SQL resultset", e);
+		}		
+		
+		return result;
+	}
+	
+	/**
+	 * Helper function to load and entire file as a String.
+	 * @param file
+	 * @return
+	 * @throws IOException
+	 */
+    private static String readEntireFile(File file) throws IOException {
+        FileReader input = new FileReader(file);
+        StringBuilder contents = new StringBuilder();
+        char[] buffer = new char[4096];
+        int read = 0;
+        do {
+            contents.append(buffer, 0, read);
+            read = input.read(buffer);
+        } while (read >= 0);
+        input.close();
+        
+        return contents.toString();
+    }
+}