/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*
*/
/* $Id: ResourceExistsAction.java 570151 2007-08-27 15:09:07Z andreas $ */
package org.apache.lenya.cms.cocoon.acting;
import java.util.Collections;
import java.util.Map;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.cocoon.acting.AbstractAction;
import org.apache.cocoon.environment.Redirector;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.excalibur.source.Source;
import org.apache.excalibur.source.TraversableSource;
/**
* This action simply checks to see if a given resource exists. It checks
* whether the specified in the src attribute source exists or not.
* The action returns empty <code>Map</code> if it exists, null otherwise.
* <p>Instead of src attribute, source can be specified using
* parameter named 'url' (this is old syntax).
* <p>In order to differentiate between files and directories, the type can be specified
* using the parameter 'type' (<map:parameter name="type" value="file"/> or
* <map:parameter name="type" value="directory"/>). The parameter 'type' is optional.
* <p>
* <strong>Note:</strong> {@link org.apache.cocoon.selection.ResourceExistsSelector}
* should be preferred to this component, as the semantics of a Selector better
* match the supplied functionality.
*/
public class ResourceExistsAction extends AbstractAction implements ThreadSafe {
/**
* @see org.apache.cocoon.acting.Action#act(org.apache.cocoon.environment.Redirector, org.apache.cocoon.environment.SourceResolver, java.util.Map, java.lang.String, org.apache.avalon.framework.parameters.Parameters)
*/
public Map act(Redirector redirector, SourceResolver resolver, Map objectModel, String source,
Parameters parameters) throws Exception {
String url = parameters.getParameter("url", source);
String type = parameters.getParameter("type", "resource");
Source src = null;
try {
src = resolver.resolveURI(url);
if (src.exists()) {
boolean isCollection = false;
if (src instanceof TraversableSource) {
TraversableSource traversableSource = (TraversableSource) src;
isCollection = traversableSource.isCollection();
}
boolean exists = type.equals("resource")
|| type.equals("file") && !isCollection
|| type.equals("directory") && isCollection;
if (exists) {
getLogger().debug(type + " exists: " + src.getURI());
return Collections.EMPTY_MAP;
}
}
getLogger().debug(".act(): Resource " + source + " as type \"" + type +
"\" does not exist");
} finally {
if (src != null) {
resolver.release(src);
}
}
return null;
}
}