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From: <vic...@us...> - 2006-07-08 22:05:27
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Revision: 7779 Author: victormote Date: 2006-07-08 15:05:19 -0700 (Sat, 08 Jul 2006) ViewCVS: http://svn.sourceforge.net/foray/?rev=7779&view=rev Log Message: ----------- Add factory class for creating URL instances. Added Paths: ----------- trunk/foray/foray-common/src/java/org/foray/common/url/URLFactory.java Added: trunk/foray/foray-common/src/java/org/foray/common/url/URLFactory.java =================================================================== --- trunk/foray/foray-common/src/java/org/foray/common/url/URLFactory.java (rev 0) +++ trunk/foray/foray-common/src/java/org/foray/common/url/URLFactory.java 2006-07-08 22:05:19 UTC (rev 7779) @@ -0,0 +1,196 @@ +/* + * Copyright 2006 The FOray Project. + * http://www.foray.org + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * This work is in part derived from the following work(s), used with the + * permission of the licensor: + * Apache FOP, licensed by the Apache Software Foundation + * + */ + +/* $Id$ */ + +package org.foray.common.url; + +import java.net.MalformedURLException; +import java.net.URL; +import java.net.URLStreamHandler; + +/** + * Creates URL instances using the FOray custom {@link URLStreamHandler} + * capabilities. + * The public methods in this class have a one-to-one correspondence with + * the {@link URL} constructors, and are intended to be a replacement for them. + * This class essentially interposes itself between the calling code and the + * {@link URL} constructors to use its own {@link URLStreamHandler} resolution. + * This is needed because there is no clean way to be assured that the + * {@link URL} constructors use the desired custom {@link URLStreamHandler} + * implementation. + * + * @see ProtocolRegistrationBroker where the various strategies for dealing with + * custom {@link URLStreamHandler} implementations are discussed, and where + * one can be selected. + */ +public class URLFactory { + + /** + * Private constructor. This should never be instantiated. + */ + private URLFactory() { } + + /** + * @see URL#URL(java.lang.String) which this method mimics. + */ + public static URL createURL(String spec) throws MalformedURLException { + /* Mimics logic in URL. */ + return createURL(null, spec); + } + + /** + * @see URL#URL(java.lang.String, java.lang.String, int, java.lang.String) + * which this method mimics. + */ + public static URL createURL(String protocol, String host, int port, + String file) throws MalformedURLException { + /* Mimics logic in URL. */ + return createURL(protocol, host, port, file, null); + } + + /** + * @see URL#URL(java.lang.String, java.lang.String, int, java.lang.String, + * java.net.URLStreamHandler) which this method mimics. + */ + public static URL createURL(String protocol, String host, int port, + String file, URLStreamHandler handler) + throws MalformedURLException { + if (handler == null) { + /* Interposes to use the custom URLStreamHandler registration. */ + handler = getCustomURLStreamHandler(protocol); + } + /* Now uses the regular URL constructor. */ + return new URL(protocol, host, port, file, handler); + } + + /** + * @see URL#URL(java.lang.String, java.lang.String, java.lang.String) + * which this method mimics. + */ + public static URL createURL(String protocol, String host, String file) + throws MalformedURLException { + /* Mimics logic in URL. */ + return createURL(protocol, host, -1, file); + } + + /** + * @see URL#URL(java.net.URL, java.lang.String) which this method mimics. + */ + public static URL createURL(URL context, String spec) + throws MalformedURLException { + /* Mimics logic in URL. */ + return createURL(context, spec, null); + } + + /** + * @see URL#URL(java.net.URL, java.lang.String, java.net.URLStreamHandler) + * which this method mimics. + */ + public static URL createURL(URL context, String spec, + URLStreamHandler handler) throws MalformedURLException { + if (handler == null) { + /* Interposes to use the custom URLStreamHandler registration. */ + String protocol = parseProtocol(spec); + handler = getCustomURLStreamHandler(protocol); + } + /* Now uses the regular URL constructor. */ + return new URL(context, spec, handler); + } + + private static URLStreamHandler getCustomURLStreamHandler(String protocol) { + return ProtocolRegistrationBroker.getURLStreamHandler(protocol); + } + + /** + * Extracts the protocol portion of a URL specification. + * @param spec The URL specifications from which a protocol should be + * extracted. + * @return The extracted protocol. + * @see URL#URL(java.net.URL, java.lang.String, java.net.URLStreamHandler) + * from which this code is derived. + */ + public static String parseProtocol(String spec) { + int i, limit, c; + int start = 0; + String newProtocol = null; + boolean aRef=false; + + limit = spec.length(); + while ((limit > 0) && (spec.charAt(limit - 1) <= ' ')) { + limit--; //eliminate trailing whitespace + } + while ((start < limit) && (spec.charAt(start) <= ' ')) { + start++; // eliminate leading whitespace + } + + if (spec.regionMatches(true, start, "url:", 0, 4)) { + start += 4; + } + if (start < spec.length() && spec.charAt(start) == '#') { + /* we're assuming this is a ref relative to the context URL. + * This means protocols cannot start w/ '#', but we must parse + * ref URL's like: "hello:there" w/ a ':' in them. + */ + aRef=true; + } + for (i = start ; !aRef && (i < limit) && + ((c = spec.charAt(i)) != '/') ; i++) { + if (c == ':') { + String s = spec.substring(start, i).toLowerCase(); + if (isValidProtocol(s)) { + newProtocol = s; + start = i + 1; + } + break; + } + } + return newProtocol; + } + + /** + * Returns true if specified string is a valid protocol name. + * This method is derived from the {@link URL} method with the same + * signature. + */ + public static boolean isValidProtocol(String protocol) { + int len = protocol.length(); + if (len < 1) { + return false; + } + char c = protocol.charAt(0); + if (! Character.isLetter(c)) { + return false; + } + for (int i = 1; i < len; i++) { + c = protocol.charAt(i); + if (! Character.isLetterOrDigit(c) + && c != '.' + && c != '+' + && c != '-') { + return false; + } + } + return true; + } + +} Property changes on: trunk/foray/foray-common/src/java/org/foray/common/url/URLFactory.java ___________________________________________________________________ Name: svn:keywords + "Author Id Rev Date URL" Name: svn:eol-style + native This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site. |
