/** * Copyright 2010 Molindo GmbH * * 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. */ package org.wicketstuff.mergedresources.versioning; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.URL; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RevisionVersionProvider extends AbstractClasspathResourceVersionProvider { private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(RevisionVersionProvider.class); public AbstractResourceVersion getVersion(URL url) throws VersionException { String line = readFirstLine(url); final Matcher m = Pattern.compile("Revision: ([0-9]+)").matcher(line); if (m.find()) { final int value = Integer.valueOf(m.group(1)); if (value <= 0) { throw new VersionException("found invalid resource version: " + value + " in " + url); } return new SimpleResourceVersion(value); } else { throw new VersionException("did not find version in " + url); } } protected String readFirstLine(URL url) throws VersionException { String line; BufferedReader r = null; try { r = new BufferedReader(new InputStreamReader(url.openStream())); line = r.readLine(); } catch (final IOException e) { throw new VersionException("failed to read line from url: " + url, e); } finally { try { if (r != null) { r.close(); } } catch (final IOException e) { log.warn("error while closing reader", e); } } return line; } }