/*
* 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.engine;
import at.newmedialab.ldpath.LDPath;
import at.newmedialab.ldpath.api.backend.RDFBackend;
import at.newmedialab.ldpath.exception.LDPathParseException;
import at.newmedialab.ldpath.model.Constants;
import at.newmedialab.ldpath.template.model.freemarker.TemplateNodeModel;
import at.newmedialab.ldpath.template.model.freemarker.TemplateStackModel;
import at.newmedialab.ldpath.template.model.freemarker.TemplateWrapperModel;
import at.newmedialab.ldpath.template.model.transformers.*;
import at.newmedialab.ldpath.template.util.FormatUtil;
import freemarker.core.Environment;
import freemarker.template.*;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
/**
* A directive for inserting values retrieved with LDPath. It can be used in several forms:
* <p/>
* <strong>Value Insertion (without body):</strong><br/>
* Allows inserting the value of a path expression. The path expression should specify an XML schema type for the
* type conversion. If no type is given, string conversion is assumed. If the expression would return several values,
* only the first result is taken.
* <p/>
* <code>
* <@ldpath path="... :: xsd:type">
* </code>
* <p/>
* <strong>Value Iteration (with body):</strong>
* Allows iterating over result nodes of a path expression. Further path expressions can be used to select the
* values of each result node.
* <p/>
* <code>
* <@ldpath path="..."><br/>
* ...<br/>
* <@ldpath path="..."><br/>
* ...<br/>
* </@ldpath>
* </code>
* <p/>
* If a loop variable is given, it will be bound to the context node. The context node is also implicitly available
* as the variable "context".
* <p/>
* Author: Sebastian Schaffert
*/
public class LDPathDirective<Node> implements TemplateDirectiveModel {
private LDPath<Node> ldpath;
private RDFBackend<Node> backend;
public LDPathDirective(RDFBackend<Node> backend) {
this.ldpath = new LDPath<Node>(backend);
this.backend = backend;
// register custom freemarker transformers for the parser so we get the results immediately in the freemarker model
ldpath.registerTransformer(Constants.NS_XSD + "string", new TemplateScalarTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "decimal", new TemplateLongTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "integer", new TemplateIntegerTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "long", new TemplateLongTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "short", new TemplateIntegerTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "double", new TemplateDoubleTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "float", new TemplateFloatTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "dateTime", new TemplateDateTransformer<Node>(TemplateDateModel.DATETIME));
ldpath.registerTransformer(Constants.NS_XSD + "date", new TemplateDateTransformer<Node>(TemplateDateModel.DATE));
ldpath.registerTransformer(Constants.NS_XSD + "time", new TemplateDateTransformer<Node>(TemplateDateModel.TIME));
ldpath.registerTransformer(Constants.NS_XSD + "boolean", new TemplateBooleanTransformer<Node>());
ldpath.registerTransformer(Constants.NS_XSD + "anyURI", new TemplateScalarTransformer<Node>());
}
/**
* Executes this user-defined directive; called by FreeMarker when the user-defined
* directive is called in the template.
*
* @param env the current processing environment. Note that you can access
* the output {@link java.io.Writer Writer} by {@link freemarker.core.Environment#getOut()}.
* @param params the parameters (if any) passed to the directive as a
* map of key/value pairs where the keys are {@link String}-s and the
* values are {@link freemarker.template.TemplateModel} instances. This is never
* <code>null</code>. If you need to convert the template models to POJOs,
* you can use the utility methods in the {@link freemarker.template.utility.DeepUnwrap} class.
* @param loopVars an array that corresponds to the "loop variables", in
* the order as they appear in the directive call. ("Loop variables" are out-parameters
* that are available to the nested body of the directive; see in the Manual.)
* You set the loop variables by writing this array. The length of the array gives the
* number of loop-variables that the caller has specified.
* Never <code>null</code>, but can be a zero-length array.
* @param body an object that can be used to render the nested content (body) of
* the directive call. If the directive call has no nested content (i.e., it is like
* [@myDirective /] or [@myDirective][/@myDirective]), then this will be
* <code>null</code>.
* @throws freemarker.template.TemplateException
*
* @throws java.io.IOException
*/
@Override
public void execute(Environment env, Map params, TemplateModel[] loopVars, TemplateDirectiveBody body) throws TemplateException, IOException {
TemplateStackModel contextStack = (TemplateStackModel)env.getVariable("context");
if(contextStack == null || contextStack.empty()) {
throw new TemplateModelException("error; no context node available");
}
TemplateNodeModel<Node> context = (TemplateNodeModel<Node>)contextStack.peek();
SimpleScalar pathScalar = (SimpleScalar)params.get("path");
if(pathScalar == null) {
throw new TemplateException("the directive has been called without a path parameter",env);
}
String path = pathScalar.getAsString();
TemplateWrapperModel<Map<String,String>> namespacesWrapped = (TemplateWrapperModel<Map<String,String>>)env.getGlobalVariable("namespaces");
Map<String,String> namespaces;
if(namespacesWrapped == null) {
namespaces = new HashMap<String, String>();
namespacesWrapped = new TemplateWrapperModel<Map<String, String>>(new HashMap<String, String>());
env.setGlobalVariable("namespaces",namespacesWrapped);
} else {
namespaces = namespacesWrapped.getAdaptedObject(Map.class);
}
if(body == null) { // value insertion
if(!path.contains("::")) {
path = path + ":: xsd:string";
}
try {
Collection results = ldpath.pathTransform(context.getNode(),path,namespaces);
if(results.size() > 0) {
Object result = results.iterator().next();
if(result instanceof TemplateNumberModel) {
env.getOut().write(FormatUtil.formatNumber( ((TemplateNumberModel)result).getAsNumber() ));
} else if(result instanceof TemplateDateModel) {
switch (((TemplateDateModel)result).getDateType()) {
case TemplateDateModel.DATE:
env.getOut().write(FormatUtil.formatDate(((TemplateDateModel)result).getAsDate()));
break;
case TemplateDateModel.TIME:
env.getOut().write(FormatUtil.formatTime(((TemplateDateModel)result).getAsDate()));
break;
case TemplateDateModel.DATETIME:
env.getOut().write(FormatUtil.formatDateTime(((TemplateDateModel)result).getAsDate()));
break;
default:
env.getOut().write(FormatUtil.formatDateTime(((TemplateDateModel)result).getAsDate()));
}
} else if(result instanceof TemplateScalarModel) {
env.getOut().write( ((TemplateScalarModel)result).getAsString() );
} else if(result instanceof TemplateBooleanModel) {
env.getOut().write( Boolean.toString(((TemplateBooleanModel)result).getAsBoolean()) );
}
} // else write nothing
} catch (LDPathParseException e) {
throw new TemplateException("invalid path for ldpath directive: "+path,e,env);
}
} else {
try {
for(Node node : ldpath.pathQuery(context.getNode(),path,namespaces)) {
contextStack.push(new TemplateNodeModel<Node>(node, backend));
if(loopVars.length > 0) {
loopVars[0] = new TemplateNodeModel<Node>(node,backend);
}
body.render(env.getOut());
contextStack.pop();
}
} catch(LDPathParseException ex) {
throw new TemplateException("invalid path for ldpath directive: "+path,ex,env);
}
}
}
}