at.newmedialab.ldpath.template.model.freemarker.TemplateNodeModel Maven / Gradle / Ivy
/*
* Copyright (c) 2011 Salzburg Research.
*
* 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 at.newmedialab.ldpath.template.model.freemarker;
import at.newmedialab.ldpath.api.backend.RDFBackend;
import freemarker.template.*;
/**
* A custom freemarker model to represent RDF nodes (implementation independent, generic)
*
* Author: Sebastian Schaffert
*/
public class TemplateNodeModel implements TemplateModel, TemplateHashModel, AdapterTemplateModel {
private Node node;
private RDFBackend backend;
public TemplateNodeModel(Node node, RDFBackend backend) {
this.node = node;
this.backend = backend;
}
public Node getNode() {
return node;
}
/**
* Gets a TemplateModel from the hash.
*
* @param key the name by which the TemplateModel
* is identified in the template.
* @return the TemplateModel referred to by the key,
* or null if not found.
*/
@Override
public TemplateModel get(String key) throws TemplateModelException {
if( ("uri".equals(key) && backend.isURI(node)) || ("content".equals(key) && backend.isLiteral(node))) {
return new TemplateScalarModel() {
@Override
public String getAsString() throws TemplateModelException {
return backend.stringValue(node);
}
};
} else if("language".equals(key) && backend.isLiteral(node)) {
return new TemplateScalarModel() {
@Override
public String getAsString() throws TemplateModelException {
return backend.getLiteralLanguage(node).getLanguage();
}
};
} else if("type".equals(key) && backend.isLiteral(node)) {
return new TemplateScalarModel() {
@Override
public String getAsString() throws TemplateModelException {
return backend.getLiteralType(node).toString();
}
};
} else if("id".equals(key) && backend.isBlank(node)) {
return new TemplateScalarModel() {
@Override
public String getAsString() throws TemplateModelException {
return backend.stringValue(node);
}
};
}
return null;
}
@Override
public boolean isEmpty() throws TemplateModelException {
return false;
}
/**
* Retrieves the underlying object, or some other object semantically
* equivalent to its value narrowed by the class hint.
*
* @param hint the desired class of the returned value. An implementation
* should make reasonable effort to retrieve an object of the requested
* class, but if that is impossible, it must at least return the underlying
* object as-is. As a minimal requirement, an implementation must always
* return the exact underlying object when
* hint.isInstance(underlyingObject) == true holds. When called
* with java.lang.Object.class, it should return a generic Java
* object (i.e. if the model is wrapping a scripting lanugage object that is
* further wrapping a Java object, the deepest underlying Java object should
* be returned).
* @return the underlying object, or its value accommodated for the hint
* class.
*/
@Override
public Object getAdaptedObject(Class hint) {
return node;
}
}