/**
* 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.
*/
package org.apache.marmotta.platform.ldpath.model.functions;
import org.apache.marmotta.platform.ldpath.api.AutoRegisteredLDPathFunction;
import org.apache.marmotta.platform.core.api.content.ContentService;
import org.apache.marmotta.kiwi.model.rdf.KiWiResource;
import org.apache.marmotta.kiwi.model.rdf.KiWiStringLiteral;
import org.apache.marmotta.ldpath.api.backend.RDFBackend;
import org.openrdf.model.Resource;
import org.openrdf.model.Value;
import org.slf4j.Logger;
import javax.annotation.PostConstruct;
import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
/**
* Add file description here!
* <p/>
* Author: Sebastian Schaffert
*/
@ApplicationScoped
public class ContentFunction extends AutoRegisteredLDPathFunction {
@Inject
private Logger log;
@Inject
private ContentService contentService;
private String[] allowedTypes = new String[] {
"text/.*", "application/([a-z]+\\+)?xml", "application/([a-z]+\\+)?json"
};
public ContentFunction() {
}
@PostConstruct
public void initialise() {
log.info("initialising LMF LDPath fn:content(...) function ...");
}
/**
* Apply the function to the list of nodes passed as arguments and return the result as type T.
* Throws IllegalArgumentException if the function cannot be applied to the nodes passed as argument
* or the number of arguments is not correct.
*
* @param context the context of the execution. Same as using the
* {@link org.apache.marmotta.ldpath.api.selectors.NodeSelector} '.' as parameter.
* @param args a nested list of KiWiNodes
* @return
*/
@Override
public Collection<Value> apply(RDFBackend<Value> kiWiNodeRDFBackend, Value context, Collection<Value>... args) throws IllegalArgumentException {
List<Value> result = new LinkedList<Value>();
for(Collection<? extends Value> nodes : args) {
for(Value n : nodes) {
if(n instanceof KiWiResource) {
Resource r = (Resource)n;
String type = contentService.getContentType(r);
if(type != null) {
for(String allowedType : allowedTypes) {
if(type.matches(allowedType)) {
byte[] data = contentService.getContentData(r,type);
String content = new String(data);
result.add(new KiWiStringLiteral(content));
break;
}
}
}
}
}
}
return result;
}
/**
* Return the representation of the NodeFunction or NodeSelector in the RDF Path Language
*
* @param backend
* @return
*/
@Override
public String getLocalName() {
return "content";
}
/**
* A string describing the signature of this node function, e.g. "fn:content(uris : Nodes) : Nodes". The
* syntax for representing the signature can be chosen by the implementer. This method is for informational
* purposes only.
*
* @return
*/
@Override
public String getSignature() {
return "fn:content(nodes : URIResourceList) : LiteralList";
}
/**
* A short human-readable description of what the node function does.
*
* @return
*/
@Override
public String getDescription() {
return "Resolve the URIs passed as argument and retrieve their content using the content reader applicable for the resource.";
}
}