uri.java

OpenJMS是一个开源的Java Message Service API 1.0.2 规范的实现,它包含有以下特性： *. 它既支持点到点（point-to-point）（PTP）模型和发布/订

    public URI( String scheme, String userinfo, String host, int port,

                String path, String queryString, String fragment )

        throws MalformedURIException

    {

        if ( scheme == null || scheme.trim().length() == 0 )

            throw new MalformedURIException( "Argument scheme is null or an empty string" );

        if ( host == null ) {

            if ( userinfo != null )

                throw new MalformedURIException( "Argument userInfo must be null if host is null" );

            if ( port != -1 )

                throw new MalformedURIException( "Argument port must be null if host is null" );

        } else if ( host.trim().length() == 0 )

            throw new IllegalArgumentException( "Argument host is an empty string" );

        if ( path != null ) {

            if ( path.indexOf('?') != -1 && queryString != null )

                throw new MalformedURIException( "Argument queryString is illegal if path includes query string" );

            if ( path.indexOf('#') != -1 && fragment != null )

                throw new MalformedURIException( "Argument fragment is illegal if path includes fragment identifier" );

        } else if ( path.trim().length() == 0 )

            throw new IllegalArgumentException( "Argument path is an empty string" );

        setScheme( scheme );

        setHost( host );

        setPort( port );

        setUserinfo( userinfo );

        setPath( path );

        setQueryString( queryString );

        setFragment( fragment );

    }





    /**

     * Initialize all fields of this URI from another URI.

     *

     * @param other the URI to copy (cannot be null)

     */

    private void initialize( URI other )

    {

        _scheme = other.getScheme();

        _userinfo = other.getUserinfo();

        _host = other.getHost();

        _port = other.getPort();

        _path = other.getPath();

        _queryString = other.getQueryString();

        _fragment = other.getFragment();

    }





    /**

     * Initializes this URI from a base URI and a URI specification string.

     * See RFC 2396 Section 4 and Appendix B for specifications on parsing

     * the URI and Section 5 for specifications on resolving relative URIs

     * and relative paths.

     *

     * @param base the base URI (may be null if uriSpec is an absolute URI)

     * @param uriSpec the URI spec string which may be an absolute or

     * relative URI (can only be null/empty if base is not null)

     * @throws MalformedURIException base is null and uriSpec is not an

     * absolute URI or uriSpec violates syntax rules

     */

    private void initialize( URI base, String uriSpec )

        throws MalformedURIException

    {

        int    uriSpecLen;

        int    index;

        int    startPos;

        char   testChar;



        if ( base == null && ( uriSpec == null || uriSpec.trim().length() == 0) )

            throw new MalformedURIException( "Argument base is null and argument uriSpec is null or an empty string" );

        // just make a copy of the base if spec is empty

        if ( uriSpec == null || uriSpec.trim().length() == 0 ) {

            initialize( base );

            return;

        }



        uriSpec = uriSpec.trim();

        uriSpecLen = uriSpec.length();

        index = 0;



        // check for scheme

        if ( uriSpec.indexOf( ':' ) == -1 ) {

            if ( base == null )

                throw new MalformedURIException( "No scheme found in URI." );

        } else {

            initializeScheme( uriSpec );

            index = _scheme.length() + 1;

        }



        // two slashes means generic URI syntax, so we get the authority

        if ( ( index + 1 < uriSpecLen ) && ( uriSpec.substring( index ).startsWith( "//" ) ) ) {

            index += 2;

            startPos = index;

            // get authority - everything up to path, query or fragment

            testChar = '\0';

            while ( index < uriSpecLen ) {

                testChar = uriSpec.charAt( index );

                if ( testChar == '/' || testChar == '?' || testChar == '#' )

                    break;

                index++;

            }



            // if we found authority, parse it out, otherwise we set the

            // host to empty string

            if ( index > startPos )

                initializeAuthority( uriSpec.substring( startPos, index ) );

            else

                _host = "";

        }



        initializePath( uriSpec.substring( index ) );



        // Resolve relative URI to base URI - see RFC 2396 Section 5.2

        // In some cases, it might make more sense to throw an exception

        // (when scheme is specified is the string spec and the base URI

        // is also specified, for example), but we're just following the

        // RFC specifications

        if ( base != null ) {



            // check to see if this is the current doc - RFC 2396 5.2 #2

            // note that this is slightly different from the RFC spec in that

            // we don't include the check for query string being null

            // - this handles cases where the urispec is just a query

            // string or a fragment (e.g. "?y" or "#s") -

            // see <http://www.ics.uci.edu/~fielding/url/test1.html> which

            // identified this as a bug in the RFC

            if ( _path.length() == 0 && _scheme == null && _host == null ) {

                _scheme = base.getScheme();

                _userinfo = base.getUserinfo();

                _host = base.getHost();

                _port = base.getPort();

                _path = base.getPath();

                if ( _queryString == null )

                    _queryString = base.getQueryString();

                return;

            }



            // check for scheme - RFC 2396 5.2 #3

            // if we found a scheme, it means absolute URI, so we're done

            if ( _scheme == null )

                _scheme = base.getScheme();

            else

                return;



            // check for authority - RFC 2396 5.2 #4

            // if we found a host, then we've got a network path, so we're done

            if ( _host == null ) {

                _userinfo = base.getUserinfo();

                _host = base.getHost();

                _port = base.getPort();

            } else

                return;



            // check for absolute path - RFC 2396 5.2 #5

            if ( _path.length() > 0 && _path.startsWith( "/" ) )

                return;



            // if we get to this point, we need to resolve relative path

            // RFC 2396 5.2 #6

            String tmpPath = new String();

            String basePath = base.getPath();



            // 6a - get all but the last segment of the base URI path

            if ( basePath != null ) {

                int lastSlash = basePath.lastIndexOf( '/' );

                if ( lastSlash != -1 )

                    tmpPath = basePath.substring( 0, lastSlash + 1 );

            }



            // 6b - append the relative URI path

            tmpPath = tmpPath.concat( tmpPath );

            // 6c - remove all "./" where "." is a complete path segment

            index = -1;

            while ( ( index = tmpPath.indexOf( "/./" ) ) != -1 )

                tmpPath = tmpPath.substring( 0, index + 1 ).concat( tmpPath.substring( index + 3 ) );



            // 6d - remove "." if path ends with "." as a complete path segment

            if ( tmpPath.endsWith("/.") )

                tmpPath = tmpPath.substring( 0, tmpPath.length() - 1 );



            // 6e - remove all "<segment>/../" where "<segment>" is a complete

            // path segment not equal to ".."

            index = -1;



            int segIndex = -1;

            String tempString = null;



            while ( ( index = tmpPath.indexOf( "/../" ) ) > 0 ) {

                tempString = tmpPath.substring( 0, tmpPath.indexOf( "/../" ) );

                segIndex = tempString.lastIndexOf( '/' );

                if ( segIndex != -1 )

                    if ( !tempString.substring( segIndex++ ).equals( ".." ) )

                        tmpPath = tmpPath.substring( 0, segIndex ).concat( tmpPath.substring( index + 4 ) );

            }



            // 6f - remove ending "<segment>/.." where "<segment>" is a

            // complete path segment

            if ( tmpPath.endsWith( "/.." ) ) {

                tempString = tmpPath.substring( 0, tmpPath.length() - 3 );

                segIndex = tempString.lastIndexOf( '/' );

                if ( segIndex != -1 )

                    tmpPath = tmpPath.substring( 0, segIndex + 1 );

            }

            _path = tmpPath;

        }

    }





    /**

     * Initialize the scheme for this URI from a URI string spec.

     *

     * @param uriSpec the URI specification (cannot be null)

     * @throws MalformedURIException URI does not have a conformant scheme

     */

    private void initializeScheme( String uriSpec )

        throws MalformedURIException

    {

        int uriSpecLen = uriSpec.length();

        int index = 0;

        String scheme = null;

        char testChar = '\0';



        while ( index < uriSpecLen ) {

            testChar = uriSpec.charAt( index );

            if ( testChar == ':' || testChar == '/' || testChar == '?' || testChar == '#' )

                break;

            index++;

        }

        scheme = uriSpec.substring( 0, index );

        if ( scheme.length() == 0 )

            throw new MalformedURIException( "No scheme found in URI." );

        else

            setScheme( scheme );

    }





    /**

     * Initialize the authority (userinfo, host and port) for this

     * URI from a URI string spec.

     *

     * @param uriSpec the URI specification (cannot be null)

     * @throws MalformedURIException uriSpec violates syntax rules

     */

    private void initializeAuthority( String uriSpec )

        throws MalformedURIException

    {

        int index = 0;

        int start = 0;

        int end = uriSpec.length();

        char testChar = '\0';

        String userinfo = null;



        // userinfo is everything up @

        if ( uriSpec.indexOf( '@', start ) != -1 ) {

            while ( index < end ) {

                testChar = uriSpec.charAt( index );

                if ( testChar == '@' )

                    break;

                index++;

            }

            userinfo = uriSpec.substring( start, index );

            index++;

        }



        // host is everything up to ':'

        String host = null;



        start = index;

        while ( index < end ) {

            testChar = uriSpec.charAt( index );

            if ( testChar == ':' )

                break;

            index++;

        }

        host = uriSpec.substring( start, index );



        int port = -1;



        if ( host.length() > 0 ) {

            // port

            if ( testChar == ':' ) {

                index++;

                start = index;

                while ( index < end )

                    index++;



                String portStr = uriSpec.substring( start, index );

                if ( portStr.length() > 0 ) {

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

                        if ( !isDigit( portStr.charAt( i ) ) )

                            throw new MalformedURIException( portStr + " is invalid. Port should only contain digits!" );

                    try {

                        port = Integer.parseInt( portStr );

                    } catch ( NumberFormatException nfe ) {

                        // can't happen

                    }

                }

            }

        }



        setHost( host );

        setPort( port );

        setUserinfo( userinfo );

    }





    /**

     * Initialize the path for this URI from a URI string spec.

     *

     * @param uriSpec the URI specification (cannot be null)

     * @throws MalformedURIException uriSpec violates syntax rules

     */

    private void initializePath( String uriSpec )

        throws MalformedURIException

    {

        if ( uriSpec == null )

            throw new MalformedURIException( "Argument uriSpec is null" );



        int index = 0;

        int start = 0;

        int end = uriSpec.length();

        char testChar = '\0';



        // path - everything up to query string or fragment

        while ( index < end ) {

            testChar = uriSpec.charAt( index );

            if ( testChar == '?' || testChar == '#' )

                break;

            // check for valid escape sequence

            if ( testChar == '%' ) {

                if ( index + 2 >= end || ! isHex( uriSpec.charAt( index + 1 ) ) ||

                     ! isHex( uriSpec.charAt( index + 2 ) ) )

                    throw new MalformedURIException( "Path contains invalid escape sequence!" );

            } else if ( ! isReservedCharacter( testChar ) &&

                        ! isUnreservedCharacter( testChar ) ) {