cn.lead2success.ddlutils.io.ColumnXmlWriter Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of ddlutils Show documentation
Fork of Apache DdlUtils project without ant support.
There is a newer version: 1.0.0_21071202
package cn.lead2success.ddlutils.io;

import cn.lead2success.ddlutils.model.Column;

/**
 * Helper class for writing columns to XML.  
 */
public class ColumnXmlWriter extends ModelXmlWriter
{
    private final int AS_TABLE_ATTRIBUTE  = 0;
    private final int AS_SUBTAG           = 1;
    private final int AS_COLUMN_ATTRIBUTE = 2;
    private final int AS_VALUE            = 3;

    private final String columnName;
    private final String columnValue;
    private final boolean nameBase64Encoded;
    private final boolean valueBase64Encoded;
    private final int columnFormattingMethod;

    /**
     * Creates a new column writer.
     * 
     * @param column The column, cannot be null
     * @param value  The value, cannot be null
     */
    public ColumnXmlWriter(Column column, String value)
    {
        /*
         * - attribute "column name"="column value" in the parent's (table) element
         *   iff the column name is a valid attribute name and is not "table-name" and not "column",
         *   and the value is a valid attribute value not longer than 255 characters
         * - otherwise, writes a sub-element  with an attribute column-name that contains the name
         *   of the column, and the body of that sub-element contains the column value,
         *   iff the column name is a valid attribute value not longer than 255 characters. If the column
         *   value contains illegal characters, then the column sub element will have a "base64" attribute
         *   with the value "true" and the value will be base64 encoded
         * - otherwise writes a sub-element  with a sub-element  whose
         *   body is the name of the column, and another sub-element  whose body contains
         *   the column value. If either the column name or value contain illegal characters, then the
         *   corresponding sub element will have a "base64" attribute with the value "true" and its body will
         *   be base64 encoded.
         */
        if (XMLUtils.hasIllegalXMLCharacters(value))
        {
            columnValue        = XMLUtils.base64Encode(value);
            valueBase64Encoded = true;
        }
        else
        {
            columnValue        = value;
            valueBase64Encoded = false;
        }

        if (XMLUtils.hasIllegalXMLCharacters(column.getName())) {
            columnName             = XMLUtils.base64Encode(column.getName());
            nameBase64Encoded      = true;
            columnFormattingMethod = AS_VALUE;
        }
        else
        {
            columnName        = column.getName();
            nameBase64Encoded = false;
            if (columnName.length() > XMLUtils.MAX_NAME_LENGTH)
            {
                columnFormattingMethod = AS_VALUE;
            }
            else if ("table-name".equals(columnName) ||
                     DatabaseIO.BASE64_ATTR_NAME.equals(columnName) ||
                     !XMLUtils.isWellFormedXMLName(columnName))
            {
                columnFormattingMethod = AS_COLUMN_ATTRIBUTE;
            }
            else if (valueBase64Encoded || (value.length() > XMLUtils.MAX_ATTRIBUTE_LENGTH))
            {
                columnFormattingMethod = AS_SUBTAG;
            }
            else
            {
                columnFormattingMethod = AS_TABLE_ATTRIBUTE;
            }
        }
    }

    /**
     * Writes the column data as an attribute of the parent element if possible.
     * Does nothing if the column name or value cannot be used in an attribute.
     * 
     * @param writer The writer to write to
     * @return true if something was written
     */
    public boolean writeAttribute(DataWriter writer)
    {
        if (columnFormattingMethod == AS_TABLE_ATTRIBUTE)
        {
            writer.writeAttribute(null, columnName, columnValue);
            return true;
        }
        else
        {
            return false;
        }
    }

    /**
     * Writes any sub elements necessary for the column. If no sub elements
     * are required, then this method does nothing.
     * 
     * @param writer The writer to write to
     * @return true if something was written
     */
    public boolean writeSubElement(DataWriter writer)
    {
        if (columnFormattingMethod != AS_TABLE_ATTRIBUTE)
        {
            writer.printlnIfPrettyPrinting();
            writer.indentIfPrettyPrinting(2);
            if (columnFormattingMethod == AS_SUBTAG)
            {
                writer.writeElementStart(null, columnName);
                writeText(writer, columnValue, valueBase64Encoded);
            }
            else
            {
                writer.writeElementStart(null, "column");
                if (columnFormattingMethod == AS_COLUMN_ATTRIBUTE)
                {
                    writer.writeAttribute(null, "column-name", columnName);
                    writeText(writer, columnValue, valueBase64Encoded);
                }
                else if (columnFormattingMethod == AS_VALUE)
                {
                    writer.printlnIfPrettyPrinting();
                    writer.indentIfPrettyPrinting(3);
                    writer.writeElementStart(null, "column-name");
                    writeText(writer, columnName, nameBase64Encoded);
                    writer.writeElementEnd();

                    writer.printlnIfPrettyPrinting();
                    writer.indentIfPrettyPrinting(3);
                    writer.writeElementStart(null, "column-value");
                    writeText(writer, columnValue, valueBase64Encoded);
                    writer.writeElementEnd();
                    writer.printlnIfPrettyPrinting();
                    writer.indentIfPrettyPrinting(2);
                }
            }
            writer.writeElementEnd();
            return true;
        }
        else
        {
            return false;
        }
    }
}