simplenlg-master/src/main/java/simplenlg/phrasespec/PPPhraseSpec.java
/*
 * The contents of this file are subject to the Mozilla Public 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
 * https://www.mozilla.org/en-US/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is "Simplenlg".
 *
 * The Initial Developer of the Original Code is Ehud Reiter, Albert Gatt and Dave Westwater.
 * Portions created by Ehud Reiter, Albert Gatt and Dave Westwater are Copyright (C) 2010-11 The University of Aberdeen. All Rights Reserved.
 *
 * Contributor(s): Ehud Reiter, Albert Gatt, Dave Westwater, Roman Kutlak, Margaret Mitchell, and Saad Mahamood.
 */

package simplenlg.phrasespec;

import java.util.List;

import simplenlg.features.DiscourseFunction;
import simplenlg.features.InternalFeature;
import simplenlg.framework.*;

/**
 * <p>
 * This class defines a prepositional phrase.  It is essentially
 * a wrapper around the <code>PhraseElement</code> class, with methods
 * for setting common constituents such as object.
 * For example, the <code>setPreposition</code> method in this class sets
 * the head of the element to be the specified preposition
 * <p>
 * From an API perspective, this class is a simplified version of the PPPhraseSpec
 * class in simplenlg V3.  It provides an alternative way for creating syntactic
 * structures, compared to directly manipulating a V4 <code>PhraseElement</code>.
 * <p>
 * Methods are provided for setting and getting the following constituents:
 * <UL>
 * <LI>Preposition		(eg, "in")
 * <LI>Object     (eg, "the shop")
 * </UL>
 * <p>
 * NOTE: PPPhraseSpec do not usually have modifiers or (user-set) features
 *
 * <code>PPPhraseSpec</code> are produced by the <code>createPrepositionalPhrase</code>
 * method of a <code>PhraseFactory</code>
 * </p>
 *
 * @author E. Reiter, University of Aberdeen.
 * @version 4.1
 */
public class PPPhraseSpec extends PhraseElement {

	public PPPhraseSpec(NLGFactory phraseFactory) {
		super(PhraseCategory.PREPOSITIONAL_PHRASE);
		this.setFactory(phraseFactory);
	}

	/**
	 * Sets the preposition (head) of a prepositional phrase.
	 *
	 * @param preposition -- Sets the preposition for this {@link PPPhraseSpec}.
	 */
	public void setPreposition(Object preposition) {
		if(preposition instanceof NLGElement)
			setHead(preposition);
		else {
			// create noun as word
			NLGElement prepositionalElement = getFactory().createWord(preposition, LexicalCategory.PREPOSITION);

			// set head of NP to nounElement
			setHead(prepositionalElement);
		}
	}

	/**
	 * @return preposition (head) of prepositional phrase
	 */
	public NLGElement getPreposition() {
		return getHead();
	}

	/**
	 * Sets the  object of a Prepositional Phrase.
	 *
	 * @param object -- Sets the object for this {@link PPPhraseSpec}.
	 */
	public void setObject(Object object) {
		PhraseElement objectPhrase = getFactory().createNounPhrase(object);
		objectPhrase.setFeature(InternalFeature.DISCOURSE_FUNCTION, DiscourseFunction.OBJECT);
		addComplement(objectPhrase);
	}

	/**
	 * @return object of PP (assume only one)
	 */
	public NLGElement getObject() {
		List<NLGElement> complements = getFeatureAsElementList(InternalFeature.COMPLEMENTS);
		for(NLGElement complement : complements)
			if(complement.getFeature(InternalFeature.DISCOURSE_FUNCTION) == DiscourseFunction.OBJECT)
				return complement;
		return null;
	}

}
