# SQLiteGeneratedKeysReader.java

    package org.codefilarete.stalactite.sql.sqlite;

    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.util.Collections;
    import java.util.List;

    import org.codefilarete.stalactite.sql.sqlite.SQLiteDatabaseSettings.SQLiteWriteOperation;
    import org.codefilarete.stalactite.sql.statement.GeneratedKeysReader;
    import org.codefilarete.stalactite.sql.statement.ReadOperation;
    import org.codefilarete.stalactite.sql.statement.SQLStatement;
    import org.codefilarete.stalactite.sql.statement.WriteOperation;
    import org.codefilarete.stalactite.sql.statement.binder.DefaultParameterBinders;
    import org.codefilarete.tool.collection.Iterables;

    /**
     * @author Guillaume Mary
     */
    public class SQLiteGeneratedKeysReader extends GeneratedKeysReader<Integer> {

    	public static final String GENERATED_KEYS_COLUMN_NAME = "last_id";

    	/**
    	 * Constructor
    	 */
    	public SQLiteGeneratedKeysReader() {
    		// SQLite doesn't support named column for generated key, we use "1" assuming this is used for autoincremented id
    		super(GENERATED_KEYS_COLUMN_NAME, DefaultParameterBinders.INTEGER_PRIMITIVE_BINDER);
    	}

    	/** Overridden to simulate generated keys for SQLite because it only returns the highest generated key */
    	@Override
    	public List<Integer> convert(WriteOperation writeOperation) {
    		// SQLite uses a function to retrieve the last inserted identifier, we have to call it and then deduce the generated values
    		// SQLite doesn't require the primary key to be an auto-increment one, as stated in the doc
    		// "On an INSERT, if the ROWID or INTEGER PRIMARY KEY column is not explicitly given a value, then it will be filled automatically with an unused integer"
    		// https://www.sqlite.org/autoinc.html
    		ReadOperation<Integer> lastInsertRowIdReader = new ReadOperation<>(new SQLStatement<Integer>(Collections.emptyMap()) {
    			@Override
    			public String getSQL() {
    				return "select last_insert_rowid() as " + GENERATED_KEYS_COLUMN_NAME;
    			}

    			@Override
    			protected void doApplyValue(Integer key, Object value, PreparedStatement statement) {

    			}
    		}, writeOperation.getConnectionProvider());

    		try (ReadOperation<Integer> readOperation = lastInsertRowIdReader) {
    			ResultSet execute = readOperation.execute();
    			List<Integer> rows = super.convert(execute);

    			// SQLite only returns one row: the highest generated key
    			int first = Iterables.first(rows);
    			// we append the missing values in incrementing order, assuming that's a one by one increment
    			for (int i = 0; i < ((SQLiteWriteOperation) writeOperation).getUpdatedRowCount(); i++) {
    				rows.add(0, first - i);
    			}
    			return rows;
    		}
    	}
    }