content: /*
   * Copyright (c) 2013 3 Round Stones Inc., Some Rights Reserved
   *
   * 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.callimachusproject.engine.expressions;
  
  import java.util.Collections;
  import java.util.List;
  
  import javax.xml.namespace.NamespaceContext;
  import javax.xml.stream.Location;
  
  import org.callimachusproject.engine.RDFParseException;
  import org.callimachusproject.engine.events.RDFEvent;
  import org.callimachusproject.engine.events.Triple;
  import org.callimachusproject.engine.model.AbsoluteTermFactory;
  import org.callimachusproject.engine.model.IRI;
  import org.callimachusproject.engine.model.Node;
  import org.callimachusproject.engine.model.PlainLiteral;
  import org.callimachusproject.engine.model.TermOrigin;
  
  public class PropertyExpression implements Expression {
  	private final AbsoluteTermFactory tf;
  	private final Location location;
  	private final String curie;
  	private final IRI property;
  
  	public PropertyExpression(String curie, NamespaceContext namespaces,
  			Location location, AbsoluteTermFactory tf) throws RDFParseException {
  		this.tf = tf;
  		this.curie = curie;
  		this.location = location;
  		int idx = curie.indexOf(":");
  		assert idx >= 0;
  		// this may not be a curie
  		if (curie.contains("://")) {
  			property = tf.iri(curie);
  		} else {
  			String prefix = curie.substring(0, idx);
  			String namespaceURI = namespaces.getNamespaceURI(prefix);
  			if (namespaceURI == null)
  				throw new RDFParseException("Undefined Prefix: " + prefix);
  			String reference = curie.substring(idx + 1);
  			property = tf.curie(namespaceURI, reference, prefix);
  		}
  	}
  
  	@Override
  	public String toString() {
  		return property.toString();
  	}
  
  	@Override
  	public Location getLocation() {
  		return location;
  	}
  
  	@Override
  	public String getTemplate() {
  		return "";
  	}
  
  	@Override
  	public String bind(ExpressionResult variables) {
  		return variables.getPropertyValue(curie, location);
  	}
  
  	@Override
  	public boolean isPatternPresent() {
  		return true;
  	}
  
  	@Override
  	public List<RDFEvent> pattern(Node subject, TermOrigin origin, Location location) {
  		PlainLiteral lit = tf.literal("");
  		lit.setOrigin(origin.term(location, property));
  		RDFEvent triple = new Triple(subject, property, lit, location);
  		return Collections.singletonList(triple);
  	}
  
  }
  