/*

 * @(#)$Id: PGAccessor.java 3619 2008-03-26 07:23:03Z yui $

 * 

 * Copyright 2006-2008 Makoto YUI

 *

 * Licensed 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.

 * 

 * Contributors:

 *     Makoto YUI - initial implementation

 */

package xbird.util.jdbc.impl;



import java.sql.SQLException;



import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import xbird.util.jdbc.*;

import xbird.util.jdbc.helper.QueryRunnerFactory;



/**

 * This is a utility class managing a database connection.

 * <DIV lang="en"></DIV>

 * <DIV lang="ja"></DIV>

 * 

 * @author Makoto YUI <yuin405+xbird@gmail.com>

 */

public class PGAccessor extends DBAccessor {



    private static final Log LOG = LogFactory.getLog(PGAccessor.class);



    public PGAccessor() {

        super();

    }



    public String getDatabaseName() {

        return "postgres";

    }



    /**

     * Escapes SQL String.

     */

    public final String escapeString(String inputString) {

        int strlen = inputString.length();

        if(strlen == 0)

            return null;

        int len = 2 + strlen + (strlen / 10);

        // make enough buffer

        StringBuffer output = new StringBuffer(len);

        for(int i = 0; i < strlen; ++i) {

            char c = inputString.charAt(i);

            switch(c) {

                case '\\':

                case '\'':

                    output.append('\\');

                    output.append(c);

                    break;

                case '\n':

                    output.append("\\n");

                case '\t':

                    output.append("\\t");

                    break;

                case '\0':

                    throw new IllegalArgumentException("\\0 not allowed");

                default:

                    output.append(c);

            }

        }

        return output.toString();

    }



    /**

     * This is just a wrapper method to 

     * <code>org.postgresql.util.PGbytea.toPGString()</code>.

     * if exception caused, return null.

     * 

     * representation between Java Byte Array and Postgres Bytea is different.

     * see detail on <code>org.postgresql.util.PGbytea.toPGString()</code>

     * 

     * @return PG bytea string of the specified byte array.

     */

    public final String toBytea(byte[] b) {

        return toPGString(b);

    }



    /**

     * Converts a java byte[] into a PG bytea string (i.e. the text

     * representation of the bytea data type)

     */

    private static String toPGString(byte[] p_buf) {

        if(p_buf == null)

            return null;

        StringBuffer l_strbuf = new StringBuffer(2 * p_buf.length);

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

            int l_int = (int) p_buf[i];

            if(l_int < 0) {

                l_int = 256 + l_int;

            }

            //we escape the same non-printable characters as the backend

            //we must escape all 8bit characters otherwise when convering

            //from java unicode to the db character set we may end up with

            //question marks if the character set is SQL_ASCII

            if(l_int < 040 || l_int > 0176) {

                //escape charcter with the form \000, but need two \\ because of

                //the parser

                l_strbuf.append("\\");

                l_strbuf.append((char) (((l_int >> 6) & 0x3) + 48));

                l_strbuf.append((char) (((l_int >> 3) & 0x7) + 48));

                l_strbuf.append((char) ((l_int & 0x07) + 48));

            } else if(p_buf[i] == (byte) '\\') {

                //escape the backslash character as \\, but need four \\\\ because

                //of the parser

                l_strbuf.append("\\\\");

            } else {

                //other characters are left alone

                l_strbuf.append((char) p_buf[i]);

            }

        }

        return l_strbuf.toString();

    }



    public boolean supportsForUpdate() {

        return true;

    }



    public boolean supportsForBulkload() {

        return true;

    }



    public BulkLoader getBulkLoader() {

        return PGLoader.INSTANCE;

    }



    protected static class PGLoader implements BulkLoader {



        private static final PGLoader INSTANCE = new PGLoader();



        private static final QueryRunner queryRunner = QueryRunnerFactory.create();



        private PGLoader() {}



        public void importTable(String tableName, String file) throws SQLException {

            if(tableName == null || file == null) {

                throw new IllegalArgumentException("Arguments MUST be non-null value.");

            }

            final String sql = "COPY " + tableName + " FROM '" + file + "'" + " WITH DELIMITER '"

                    + COLUMN_DELIMITER + "'";

            int count = queryRunner.update(sql);

            if(LOG.isInfoEnabled())

                LOG.info("update the table '" + tableName + "' (" + count + ") successfully.");

        }

    }

}