/*

* Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package com.nokia.mj.impl.storage;

/**

 * StorageAttribute represents one attribute in JavaStorageEntry. It is

 * basically a key value pair and it holds one storage column information.

 */

public final class StorageAttribute implements StorageNames

{

    /**

     * Escape delimiter is used to escape such characters that cannot exists

     * in SQL statement column value.

     */

    private static final char ESCAPE_CHAR_SQUOTE = '\'';

    private String iName;

    private String iValue;

    private int iType;

    /**

     * StorageAttribute value type Int.

     */

    public static final int INT_TYPE = 1;

    /**

     * StorageAttribute value type String. Default type.

     */

    public static final int STRING_TYPE = 2;

    /**

     * StorageAttribute value type NULL.

     */

    public static final int NULL_TYPE = 3;

    private StorageAttribute() {}

    /**

     * Constructor. Create attribute based on name and value. Type is set to

     * default i.e. STRING_TYPE.

     *

     * @param aName attribute name.

     * @param aValue attribute value. Null value is converted to empty String.

     * @throws StorageException if name is null or empty and if value type

     *         is unsupported.

     */

    public StorageAttribute(String aName, String aValue)

    throws StorageException

    {

        setAttribute(aName, aValue, STRING_TYPE);

    }

    /**

     * Constructor. Create attribute based on name, value and type.

     *

     * @param aName attribute name.

     * @param aValue attribute value. Null value is converted to empty String.

     * @param aAttributeType attribute type.

     * @throws StorageException if name is null or empty and if value type

     *         is unsupported.

     */

    public StorageAttribute(String aName, String aValue, int aAttributeType)

    throws StorageException

    {

        setAttribute(aName, aValue, aAttributeType);

    }

    /*** ----------------------------- PUBLIC ------------------------------ */

    /**

     * Set attribute. Overrides existing value.

     *

     * @param aName attribute name.

     * @param aValue attribute value. If value is null type is set

     *               to NULL_TYPE.

     * @param aAttributeType type of attribute.

     * @throws StorageException if name is null or empty of value type

     *         is unsupported.

     */

    public void setAttribute(String aName, String aValue, int aAttributeType)

    throws StorageException

    {

        if (aName == null || aName.equals(""))

        {

            throw new StorageException("Invalid name argument");

        }

        if (aAttributeType < INT_TYPE || aAttributeType > NULL_TYPE)

        {

            throw new StorageException("Invalid type argument");

        }

        iName = aName;

        if (aValue == null || aAttributeType == NULL_TYPE)

        {

            iValue = "NULL";

            iType = NULL_TYPE;

        }

        else

        {

            iValue = aValue;

            iType = aAttributeType;

        }

    }

    /**

     * Get attribute name.

     *

     * @return name.

     */

    public String getName()

    {

        return iName;

    }

    /**

     * Get attribute value.

     *

     * @return value. If value is not set null is returned.

     */

    public String getValue()

    {

        if (iType != NULL_TYPE)

            return iValue;

        else

            return null;

    }

    /**

     * Get attribute type.<p>

     * NOTE: Attribute type is not stored to database. This is used

     * by the storage clients to inform StorageSession of INT value.

     * When reading data from storage all attributes have default type value

     * that is StorageSession.STRING_TYPE.

     *

     * @return type.

     */

    public int getType()

    {

        return iType;

    }

    /**

     * Print StorageAttribute as String.

     *

     * @return attribute in String format. NAME='VALUE' Type: TYPE'

     */

    public String toString()

    {

        return iName + "='" + iValue + "' Type: " + Integer.toString(iType);

    }

    /**

     * Returns a hash code value for this object.

     */

    public int hashCode()

    {

        return iName.hashCode() + iValue.hashCode() + iType;

    }

    /**

     * Indicates whether given object is equal to this one.

     */

    public boolean equals(Object aObj)

    {

        if (!(aObj instanceof StorageAttribute))

        {

            return false;

        }

        StorageAttribute attr = (StorageAttribute) aObj;

        if (this.getName().equals(attr.getName())

                && this.getValue().equals(attr.getValue())

                && this.getType() == attr.getType())

        {

            return true;

        }

        return false;

    }

    /*** ------------------------ PACKAGE PROTECTED ------------------------ */

    /**

     * Escape value. This is used internally when storage query is constructed.

     *

     * @return escaped StorageAttribute value.

     */

    String getEscapedValue()

    {

        if (iValue.indexOf(ESCAPE_CHAR_SQUOTE) != -1)

        {

            return escape();

        }

        else

        {

            return iValue;

        }

    }

    /*** ----------------------------- PACKAGE ---------------------------- */

    /*** ----------------------------- PRIVATE ---------------------------- */

    /**

     * Escape attribute value.

     *

     * @param  aValue to be escaped.

     * @return escaped string.

     */

    private String escape()

    {

        StringBuffer escapedVal = new StringBuffer(iValue);

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

        {

            if (escapedVal.charAt(i) == ESCAPE_CHAR_SQUOTE)

            {

                escapedVal.insert(i, ESCAPE_CHAR_SQUOTE);

                i++;

            }

        }

        return escapedVal.toString();

    }

    /*** ----------------------------- NATIVE ----------------------------- */

}