/*

* 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.microedition.m2g.connection;

import java.io.IOException;

import java.lang.NullPointerException;

import java.lang.IllegalArgumentException;

import com.nokia.mj.impl.utils.Logger;

/**

 * Connection policy

 */

public class M2GUrlTokenizer

{

    //--------------------------------------------------

    // STATIC CONSTANTS

    //--------------------------------------------------

    public static final String PROTOCOL_SEPARATOR =

        "://";

    public static final char PARAMETER_SEPARATOR =

        '?';

    public static final char SEPARATOR =

        '/';

    //--------------------------------------------------

    // VARIABLES

    //--------------------------------------------------

    private String iUrl = null;

    private String iBaseUrl = null;

    //--------------------------------------------------

    // METHODS

    //--------------------------------------------------

    /**

     * Ctor

     */

    public M2GUrlTokenizer()

    {

    }

    /**

     * Ctor

     * @param aUrl Locator

       * @throws NullPointerException if the locator is null.

       * @throws IllegalArgumentException if the locator is of unsupported type.

     */

    public M2GUrlTokenizer(String aUrl)

    {

        setUrl(aUrl);

    }

    /**

     * Check if the url begin with slash ('/')

     * @return true is the url begin with slash

       */

    public boolean beginWithSlash()

    {

        if ((iUrl != null) &&

                (iUrl.indexOf(SEPARATOR) == 0))

        {

            return true;

        }

        return false;

    }

    /**

     * Parses the base part of the locator

     * @return parsed base part

       */

    public String getBasePart()

    {

        if (iUrl == null)

        {

            return null;

        }

        int pos = iUrl.indexOf(PARAMETER_SEPARATOR);

        if (pos == -1)

        {

            pos = iUrl.length();

        }

        return iUrl.substring(0, pos);

    }

    /**

     * Parses the base url

     * @return parsed base url

       */

    public String getBaseUrl()

    {

        return iBaseUrl;

    }

    /**

     * Parses the end part of the locator

     * @return parsed end part

     * @throws IllegalArgumentException if base part cannot

     *       be parsed from the locator

       */

    public String getEndPart()

    {

        if (iUrl == null)

        {

            return null;

        }

        int pos = iUrl.lastIndexOf(SEPARATOR);

        if (pos == -1)

        {

            return iUrl;

        }

        return iUrl.substring(pos, iUrl.length());

    }

    /**

     * Parses the middle part of the locator

     * @return parsed middle part

     * @throws IllegalArgumentException if middle part cannot

     *       be parsed from the locator

       */

    public String getMiddlePart()

    {

        if (iUrl == null)

        {

            return null;

        }

        int pos = iUrl.indexOf(PARAMETER_SEPARATOR);

        if (pos == -1)

        {

            pos = iUrl.length();

        }

        return iUrl.substring(

                   getProtocol().length() + PROTOCOL_SEPARATOR.length(), pos);

    }

    /**

     * Parses possible parameters of the locator

     * @return Parsed parameters or null if there are not parameters

     */

    public String getParameters()

    {

        if (iUrl == null)

        {

            return null;

        }

        int pos = iUrl.indexOf(PARAMETER_SEPARATOR);

        String parameters = null;

        if (pos != -1)

        {

            parameters = iUrl.substring(pos + 1);

        }

        return parameters;

    }

    /**

       * Parses the protocol part of the locator.

       * @see M2GUrlTokenizer#isAbsolutURL()

       * @return Protocol

       * @throws IllegalArgumentException If the locator is of

       * unsupported type.

       */

    public String getProtocol()

    {

        int pos = -1;

        if ((iUrl == null) || ((pos = iUrl.indexOf(PROTOCOL_SEPARATOR)) == -1))

        {

            throw new IllegalArgumentException("Unable to parse protocol");

        }

        return iUrl.substring(0, pos);

    }

    /**

     * Returns a whole locator string

     * @return Locator used to create this instance

     */

    public String getUrl()

    {

        return iUrl;

    }

    /**

     * Resolve URL according to existing base url and

     * the given relative url

     * @aRelativeUrl Relative URL.

     * @return Resolved URL

     */

    public String resolveUrl(String aRelativeUrl)

    {

        check(aRelativeUrl);

        if (iBaseUrl != null)

        {

            return (iBaseUrl + aRelativeUrl);

        }

        else

        {

            return aRelativeUrl;

        }

    }

    /**

     * Set a locator string

     * @param aUrl Locator

       * @throws NullPointerException if the locator is null.

       * @throws IllegalArgumentException if the locator is of unsupported type.

     */

    public void setUrl(String aUrl)

    {

        check(aUrl);

        iUrl = aUrl;

        int pos = iUrl.lastIndexOf(SEPARATOR);

        if (pos == -1)

        {

            iBaseUrl = null;

        }

        else

        {

            iBaseUrl = iUrl.substring(0, (pos + 1));

        }

    }

    /**

     * Check url

     * @param aUrl Locator

       * @throws NullPointerException if the locator is null.

       * @throws IllegalArgumentException if the locator is of unsupported type.

     */

    private void check(String aUrl)

    {

        if (aUrl == null)

        {

            Logger.ELOG(Logger.EJavaUI, "setUrl() - url is null");

            throw new NullPointerException();

        }

        if (aUrl.length() == 0)

        {

            Logger.ELOG(Logger.EJavaUI, "setUrl() - url is illegal");

            throw new IllegalArgumentException();

        }

    }

    //--------------------------------------------------

    // STATIC METHODS

    //--------------------------------------------------

    /**

       * Check if contains protocol.

       * An absolute URL contains the name of the scheme being used (<scheme>)

       * followed by a colon (":") and then a string (the <scheme-specific-

       * // part>) whose interpretation depends on the scheme.

       * Also if the URL begins with a slash character "/" then the URL is treated

       * as absolute.

       * @param aUrl URL

       * @return true if URL contains a protocol

       */

    static public boolean isAbsolutURL(String aUrl)

    {

        if ((aUrl == null) ||

                ((aUrl.indexOf(PROTOCOL_SEPARATOR) == -1) &&

                 (aUrl.indexOf(SEPARATOR) != 0)))

        {

            return false;

        }

        return true;

    }

}