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package com.hardcode.gdbms.engine.data.edition;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import com.hardcode.driverManager.DriverLoadException;

import com.hardcode.gdbms.driver.exceptions.OpenDriverException;

import com.hardcode.gdbms.driver.exceptions.ReadDriverException;

import com.hardcode.gdbms.driver.exceptions.WriteDriverException;

import com.hardcode.gdbms.engine.data.DataSourceFactory;

import com.hardcode.gdbms.engine.data.InnerDBUtils;

import com.hardcode.gdbms.engine.data.db.DBDataSourceAdapter;

import com.hardcode.gdbms.engine.data.db.DBTableSourceInfo;

import com.hardcode.gdbms.engine.data.driver.AlphanumericDBDriver;

import com.hardcode.gdbms.engine.values.Value;

import com.hardcode.gdbms.engine.values.ValueCollection;

import com.hardcode.gdbms.engine.values.ValueWriter;

/**

 * DataSource with write capabilities over a internal database source.

 *

 * @author Fernando Gonz?lez Cort?s

 */

public class InternalBuffer extends DBDataSourceAdapter {

    private Statement s;

    private ResultSet rs;

    private String[] pkNames;

    private String[] fieldNames;

    private int[] pkIndices;

    private int lastInserted = 0;

    private int rowCount;

    private boolean refreshNeeded = true;

    /**

     * Creates a new InternalBufferDataWare object.

     *

     * @param dsf DataSourceFactory

     * @param pkNames primary key field names

     * @param names field names

     * @param types field types

     * @throws ReadDriverException TODO

     */

    public InternalBuffer(DataSourceFactory dsf, String[] pkNames,

                String[] names, int[] types) throws ReadDriverException {

            try {

                this.dsf = dsf;

                //Add a secuential number

                String databaseName = dsf.getTempFile();

                String tableName = "gdbms";

                    InnerDBUtils.execute(databaseName,

                        InnerDBUtils.getCreateStatementWithAutonumeric(tableName,

                            names, types));

                    InnerDBUtils.execute(databaseName,

                        InnerDBUtils.getPKIndexStatement(tableName, pkNames));

                //Cache of metadata

                this.pkNames = pkNames;

                this.fieldNames = names;

                //DataSource configuration

                DBTableSourceInfo di = new DBTableSourceInfo();

                di.name = tableName;

                di.dbName = databaseName;

                di.tableName = tableName;

                di.driverName = "GDBMS HSQLDB driver";

                setSourceInfo(di);

                        setDriver((AlphanumericDBDriver) dsf.getDriverManager().getDriver(di.driverName));

                        rowCount = 0;

            } catch (SQLException e) {

                throw new ReadDriverException(getName(),e);

                } catch (DriverLoadException e) {

                throw new ReadDriverException(getName(),e);

            }

    }

    /**

     * @throws ReadDriverException TODO

     * @throws WriteDriverException

     * @see com.hardcode.gdbms.engine.data.edition.DataWare#deleteRow(long)

     */

    public void deleteRow(long rowId) throws ReadDriverException, WriteDriverException {

        //Get the pk values

        ValueCollection pks = getPKValue(rowId);

        String[] names = getFieldNames();

        String sql = InnerDBUtils.createDeleteStatement(pks.getValues(), names, tableName, ValueWriter.internalValueWriter);

        try {

            s.execute(sql.toString());

            rowCount--;

            refreshNeeded = true;

        } catch (SQLException e) {

            throw new WriteDriverException(getName(),e);

        }

    }

    /**

     * Inserts a row with data

     *

     * @param values values of the data to be inserted

     *

     * @return index where the row is inserted

     * @throws ReadDriverException TODO

     * @throws WriteDriverException

     */

    public long insertFilledRow(Value[] values) throws ReadDriverException, WriteDriverException {

        /*

         * the last field is the automuneric gdbmsindex

         */

        String[] names = new String[getFieldCount() - 1];

        System.arraycopy(getFieldNames(), 0, names, 0, names.length);

        String sql = InnerDBUtils.createInsertStatement(tableName, values, names, ValueWriter.internalValueWriter);

        try {

            s.execute(sql);

            rowCount++;

            refreshNeeded = true;

            return rowCount - 1;

        } catch (SQLException e) {

            throw new WriteDriverException(getName(),e);

        }

    }

    /**

     * Inserts a new row with only the pk values

     *

     * @param pk value of the PK

     *

     * @return index where the row is inserted

     * @throws WriteDriverException TODO

     */

    public long insertRow(ValueCollection pk) throws WriteDriverException {

        Value[] pks = pk.getValues();

        String sql = InnerDBUtils.createInsertStatement(tableName, pks, pkNames, ValueWriter.internalValueWriter);

        try {

            s.execute(sql);

            rowCount++;

            refreshNeeded = true;

            return rowCount - 1;

        } catch (SQLException e1) {

            throw new WriteDriverException(getName(),e1);

        }

    }

    /**

     * Set the modified row at the specified index

     *

     * @param row index of the row to update

     * @param modifiedRow Value array with the update

     * @throws WriteDriverException TODO

     */

    public void setRow(long row, Value[] modifiedRow) throws WriteDriverException {

             try {

                        Value[] pks = new Value[getPkIndices().length];

                        for (int i = 0; i < pks.length; i++) {

                                pks[i] = getFieldValue(row, getPkIndices()[i]);

                        }

                        String sql = InnerDBUtils.createUpdateStatement(tableName, pks,

                                        pkNames, fieldNames, modifiedRow,

                                        ValueWriter.internalValueWriter);

                        s.execute(sql);

                        refreshNeeded = true;

                } catch (SQLException e) {

                        throw new WriteDriverException(getName(),e);

                } catch (ReadDriverException e) {

                        throw new WriteDriverException(getName(),e);

                }

    }

    /**

         * @throws WriteDriverException TODO

     * @see com.hardcode.gdbms.engine.data.edition.DataWare#setFieldValue(long,

         *      int, com.hardcode.gdbms.engine.values.Value)

         */

    public void setFieldValue(long row, int modifiedField, Value modifiedValue)

        throws WriteDriverException {

             try {

            ValueCollection pk = getPKValue(row);

        Value[] pks = getPKValue(row).getValues();

        String[] names = new String[pk.getValueCount()];

        for (int i = 0; i < pk.getValueCount(); i++) {

            names[i] = getPKName(i);

        }

        String sql = InnerDBUtils.createUpdateStatement(tableName, pks, names,

                new String[] { getFieldName(modifiedField) },

                new Value[] { modifiedValue }, ValueWriter.internalValueWriter);

            s.execute(sql);

            refreshNeeded = true;

        } catch (SQLException e) {

            throw new WriteDriverException(getName(),e);

        } catch (ReadDriverException e) {

                 throw new WriteDriverException(getName(),e);

                }

    }

    /**

     * @see com.hardcode.gdbms.engine.data.DataSource#start()

     */

    public void start() throws ReadDriverException {

        try {

            con = this.getConnection();

            String localSql = sql + " ORDER BY GDBMSINDEX";

            ((AlphanumericDBDriver) driver).open(con, localSql);

            s = con.createStatement();

        } catch (SQLException e) {

            throw new ReadDriverException(getName(),e);

        } catch (OpenDriverException e) {

                 throw new ReadDriverException(getName(),e);

                }

    }

    /**

     * @see com.hardcode.gdbms.engine.data.DataSource#stop()

     */

    public void stop() throws ReadDriverException {

        try {

            s.close();

            con.close();

            con = null;

        } catch (SQLException e) {

            throw new ReadDriverException(getName(),e);

        }

    }

    /**

     * Gets a int array containing the field index of the primary key fields

     *

     * @return int[]

     * @throws ReadDriverException TODO

     */

    private int[] getPkIndices() throws ReadDriverException {

        if (pkIndices == null) {

            pkIndices = new int[pkNames.length];

            for (int i = 0; i < pkIndices.length; i++) {

                this.pkIndices[i] = getFieldIndexByName(pkNames[i]);

            }

        }

        return pkIndices;

    }

    /**

     * @see com.hardcode.gdbms.engine.data.DataSource#getPKValue(long)

     */

    public ValueCollection getPKValue(long rowIndex) throws ReadDriverException {

        refresh();

        return super.getPKValue(rowIndex);

    }

    /**

     * @see com.hardcode.gdbms.engine.data.driver.ObjectDriver#getFieldValue(long,

     *      int)

     */

    public Value getFieldValue(long rowIndex, int fieldId)

        throws ReadDriverException {

        refresh();

        return super.getFieldValue(rowIndex, fieldId);

    }

    /**

     * Rereads the information if has been modified

     * since last refresh

     * @throws ReadDriverException TODO

     */

    private void refresh() throws ReadDriverException {

        if (refreshNeeded == true) {

            stop();

            start();

            refreshNeeded = false;

        }

    }

}