com.googlecode.paradox.function.string.LPadFunction Maven / Gradle / Ivy

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/*
 * Copyright (c) 2009 Leonardo Alves da Costa
 *
 * This program 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. This program 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 this
 * program. If not, see .
 */
package com.googlecode.paradox.function.string;

import com.googlecode.paradox.ConnectionInfo;
import com.googlecode.paradox.planner.nodes.FieldNode;
import com.googlecode.paradox.results.Column;
import com.googlecode.paradox.results.ParadoxType;
import com.googlecode.paradox.rowset.ValuesConverter;

import java.sql.SQLException;

/**
 * The SQL LEFT PAD function.
 *
 * @since 1.6.0
 */
public class LPadFunction extends AbstractStringFunction {

    /**
     * The function name.
     */
    public static final String NAME = "LPAD";

    /**
     * Column parameter list.
     */
    private static final Column[] COLUMNS = {
            new Column(null, ParadoxType.VARCHAR, "The left-padded string.", 0, true, RESULT),
            new Column("string", ParadoxType.VARCHAR, "The original string.", 1, false, IN),
            new Column("length", ParadoxType.VARCHAR, "The length of the final string.", 2, false, IN),
            new Column("lpad_string", ParadoxType.VARCHAR, "The filler string to use.", 3, false, IN)
    };

    /**
     * Creates a new instance.
     */
    public LPadFunction() {
        super();
    }

    @Override
    public String getRemarks() {
        return "Left-pads a string with another string, to a certain length.";
    }

    @Override
    public Column[] getColumns() {
        return COLUMNS;
    }

    @Override
    public Object execute(final ConnectionInfo connectionInfo, final Object[] values, final ParadoxType[] types,
                          final FieldNode[] fields) throws SQLException {

        final String value = values[0].toString();
        final int size = ValuesConverter.getPositiveInteger(values[1], connectionInfo);
        if (value.length() > size) {
            return value.substring(0, size);
        }

        final String pattern = values[2].toString();
        final StringBuilder ret = new StringBuilder();
        while (ret.length() + value.length() < size) {
            ret.append(pattern);
        }

        return ret.substring(0, size - value.length()) + value;
    }
}