| /* |
| * Copyright 1999-2004 The Apache Software Foundation. |
| * |
| * 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.apache.cocoon.components.modules.input; |
| |
| import org.apache.avalon.framework.configuration.Configuration; |
| import org.apache.avalon.framework.configuration.ConfigurationException; |
| import org.apache.avalon.framework.service.ServiceException; |
| import org.apache.avalon.framework.service.ServiceManager; |
| import org.apache.avalon.framework.service.Serviceable; |
| import org.apache.avalon.framework.thread.ThreadSafe; |
| |
| import org.apache.excalibur.source.Source; |
| import org.apache.excalibur.source.SourceResolver; |
| |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.TreeSet; |
| import java.util.Vector; |
| |
| /** |
| * Locate a resource in a resource tree. Any attribute name is interpreted as a |
| * URI with the last part being the resource name unless it ends with a slash. |
| * The URI is checked if the resource exists and the URI is returned. If the |
| * resource does not exist, the URI is shortened until the resource name is found |
| * and the new URI is returned. If no resource with the given name exists, null |
| * is returned. |
| * |
| * <p>A use case is to locate the closest menu file or when moving a site from |
| * a filesystem path == URL system from a httpd to Cocoon and provide similar |
| * functions to .htaccess files.</p> |
| * |
| * <p>Example: for context:/some/path/to/a/file.xml the following URIs |
| * are tested: context:/some/path/to/a/file.xml, context:/some/path/to/file.xml, |
| * context:/some/path/file.xml, context:/some/file.xml, and context:/file.xml. |
| * For the attribute name context:/some/path/foo/ tests context:/some/path/foo/, |
| * context:/some/path/, context:/some/, and context:/ are tested.</p> |
| * |
| * <p>The getAttribute() method will return the URI for the first match while |
| * getAttributeValues() will return an array of all existing paths. |
| * getAttributeNames() will return an Iterator to an empty collection.</p> |
| * |
| * @version $Id$ |
| */ |
| public class LocateResource extends AbstractInputModule implements Serviceable, ThreadSafe { |
| |
| protected static Collection col; |
| static { |
| col = new TreeSet(); |
| } |
| |
| protected ServiceManager manager; |
| |
| /** |
| * Calculate the minimal length of the URL, that is the position |
| * of the first ":" if a protocol is provided or otherwise 0. |
| * @param name |
| * @return minimal length |
| */ |
| protected int calculateMinLen(String name) { |
| |
| int minLen = name.indexOf(':'); |
| minLen = (minLen == -1 ? 0 : minLen); |
| |
| return minLen; |
| } |
| |
| /** |
| * Remove one path element from the URL unless minimum length has |
| * been reached. |
| * |
| * @param urlstring |
| * @param minLen |
| * @return shortened URI |
| */ |
| protected String shortenURI(String urlstring, int minLen) { |
| |
| int idx = urlstring.lastIndexOf('/'); |
| idx = (idx <= minLen + 1) ? minLen : idx; |
| urlstring = urlstring.substring(0, idx); |
| |
| return urlstring; |
| } |
| |
| /** |
| * if the url does not end with a "/", keep the last part in |
| * order to add it later again after traversing up |
| */ |
| protected String extractFilename(String urlstring) { |
| |
| String filename = ""; |
| if (!urlstring.endsWith("/")) { |
| int idx = urlstring.lastIndexOf('/'); |
| filename = urlstring.substring(idx); |
| } |
| |
| return filename; |
| } |
| |
| /** |
| * Locate a resource with the given URL consisting of urlstring + filename. |
| * The filename is appended each time the path is shortened. Returns the first |
| * existing occurance. |
| * |
| * @param urlstring |
| * @param filename |
| * @param minLen |
| * @return urlstring if resource was found, <code>null</code> otherwise |
| */ |
| protected String locateResource(String urlstring, String filename, int minLen) { |
| String sourcename = null; |
| Source src = null; |
| SourceResolver resolver = null; |
| boolean found = false; |
| try { |
| resolver = |
| (SourceResolver) this.manager.lookup( |
| org.apache.excalibur.source.SourceResolver.ROLE); |
| while (!found && urlstring.length() > minLen) { |
| sourcename = urlstring + filename; |
| try { |
| src = resolver.resolveURI(sourcename); |
| if (src.exists()) |
| found = true; |
| } catch (Exception e) { |
| if (this.getLogger().isWarnEnabled()) |
| this.getLogger().warn("Exception resolving URL " + sourcename, e); |
| } finally { |
| resolver.release(src); |
| } |
| if (!found) { |
| urlstring = shortenURI(urlstring, minLen); |
| } |
| } |
| } catch (ServiceException e1) { |
| if (this.getLogger().isErrorEnabled()) |
| this.getLogger().error("Exception obtaining source resolver ", e1); |
| } finally { |
| if (resolver != null) { |
| this.manager.release(resolver); |
| } |
| } |
| return (found ? urlstring : null); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.avalon.framework.service.Serviceable#service(org.apache.avalon.framework.service.ServiceManager) |
| */ |
| public void service(ServiceManager manager) throws ServiceException { |
| this.manager = manager; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.cocoon.components.modules.input.InputModule#getAttribute(java.lang.String, org.apache.avalon.framework.configuration.Configuration, java.util.Map) |
| */ |
| public Object getAttribute(String name, Configuration modeConf, Map objectModel) |
| throws ConfigurationException { |
| |
| String urlstring = name; |
| String filename = extractFilename(urlstring); |
| int minLen = calculateMinLen(name); |
| if (filename != "") { |
| urlstring = shortenURI(urlstring, minLen); |
| } |
| |
| String result = locateResource(urlstring, filename, minLen); |
| result = (result == null? result : result + filename); |
| if (this.getLogger().isDebugEnabled()) |
| this.getLogger().debug( |
| "located " + name + " @ " + result); |
| return result; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.cocoon.components.modules.input.InputModule#getAttributeNames(org.apache.avalon.framework.configuration.Configuration, java.util.Map) |
| */ |
| public Iterator getAttributeNames(Configuration modeConf, Map objectModel) |
| throws ConfigurationException { |
| // return an iterator to an empty collection |
| return LocateResource.col.iterator(); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.cocoon.components.modules.input.InputModule#getAttributeValues(java.lang.String, org.apache.avalon.framework.configuration.Configuration, java.util.Map) |
| */ |
| public Object[] getAttributeValues(String name, Configuration modeConf, Map objectModel) |
| throws ConfigurationException { |
| |
| Vector uris = null; |
| String urlstring = name; |
| String filename = extractFilename(urlstring); |
| int minLen = calculateMinLen(name); |
| if (filename != "") { |
| urlstring = shortenURI(urlstring, minLen); |
| } |
| |
| while (urlstring != null && urlstring.length() > minLen) { |
| urlstring = this.locateResource(urlstring, filename, minLen); |
| if (urlstring != null) { |
| if (uris == null) |
| uris = new Vector(); |
| if (this.getLogger().isDebugEnabled()) |
| this.getLogger().debug("-> located " + name + " @ " + urlstring + filename); |
| uris.add(urlstring + filename); |
| urlstring = shortenURI(urlstring, minLen); |
| } |
| } |
| return (uris == null ? null : uris.toArray()); |
| } |
| |
| } |
