simplenlg-master/src/main/java/simplenlg/syntax/english/SyntaxProcessor.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.syntax.english;

import java.util.ArrayList;
import java.util.List;

import simplenlg.features.Feature;
import simplenlg.framework.*;

/**
 * <p>
 * This is the processor for handling syntax within the SimpleNLG. The processor
 * translates phrases into lists of words.
 * </p>
 *
 * <p>
 * All processing modules perform realisation on a tree of
 * <code>NLGElement</code>s. The modules can alter the tree in whichever way
 * they wish. For example, the syntax processor replaces phrase elements with
 * list elements consisting of inflected words while the morphology processor
 * replaces inflected words with string elements.
 * </p>
 *
 * <p>
 * <b>N.B.</b> the use of <em>module</em>, <em>processing module</em> and
 * <em>processor</em> is interchangeable. They all mean an instance of this
 * class.
 * </p>
 *
 * @author D. Westwater, University of Aberdeen.
 * @version 4.0
 */
public class SyntaxProcessor extends NLGModule {

	@Override
	public void initialise() {
		// Do nothing
	}

	@Override
	public NLGElement realise(NLGElement element) {
		NLGElement realisedElement = null;

		if(element != null && !element.getFeatureAsBoolean(Feature.ELIDED).booleanValue()) {

			if(element instanceof DocumentElement) {
				List<NLGElement> children = element.getChildren();
				((DocumentElement) element).setComponents(realise(children));
				realisedElement = element;

			} else if(element instanceof PhraseElement) {
				realisedElement = realisePhraseElement((PhraseElement) element);

			} else if(element instanceof ListElement) {
				realisedElement = new ListElement();
				((ListElement) realisedElement).addComponents(realise(element.getChildren()));

			} else if(element instanceof InflectedWordElement) {
				String baseForm = ((InflectedWordElement) element).getBaseForm();
				ElementCategory category = element.getCategory();

				if(this.lexicon != null && baseForm != null) {
					WordElement word = ((InflectedWordElement) element).getBaseWord();

					if(word == null) {
						if(category instanceof LexicalCategory) {
							word = this.lexicon.lookupWord(baseForm, (LexicalCategory) category);
						} else {
							word = this.lexicon.lookupWord(baseForm);
						}
					}

					if(word != null) {
						((InflectedWordElement) element).setBaseWord(word);
					}
				}

				realisedElement = element;

			} else if(element instanceof WordElement) {
				// AG: need to check if it's a word element, in which case it
				// needs to be marked for inflection
				InflectedWordElement infl = new InflectedWordElement((WordElement) element);

				// // the inflected word inherits all features from the base
				// word
				for(String feature : element.getAllFeatureNames()) {
					infl.setFeature(feature, element.getFeature(feature));
				}

				realisedElement = realise(infl);

			} else if(element instanceof CoordinatedPhraseElement) {
				realisedElement = CoordinatedPhraseHelper.realise(this, (CoordinatedPhraseElement) element);

			} else {
				realisedElement = element;
			}
		}

		// Remove the spurious ListElements that have only one element.
		if(realisedElement instanceof ListElement) {
			if(((ListElement) realisedElement).size() == 1) {
				realisedElement = ((ListElement) realisedElement).getFirst();
			}
		}

		return realisedElement;
	}

	@Override
	public List<NLGElement> realise(List<NLGElement> elements) {
		List<NLGElement> realisedList = new ArrayList<NLGElement>();
		NLGElement childRealisation = null;

		if(elements != null) {
			for(NLGElement eachElement : elements) {
				if(eachElement != null) {
					childRealisation = realise(eachElement);
					if(childRealisation != null) {
						if(childRealisation instanceof ListElement) {
							realisedList.addAll(((ListElement) childRealisation).getChildren());
						} else {
							realisedList.add(childRealisation);
						}
					}
				}
			}
		}
		return realisedList;
	}

	/**
	 * Realises a phrase element.
	 *
	 * @param phrase the element to be realised
	 * @return the realised element.
	 */
	private NLGElement realisePhraseElement(PhraseElement phrase) {
		NLGElement realisedElement = null;

		if(phrase != null) {
			ElementCategory category = phrase.getCategory();

			if(category instanceof PhraseCategory) {
				switch((PhraseCategory) category){

				case CLAUSE:
					realisedElement = ClauseHelper.realise(this, phrase);
					break;

				case NOUN_PHRASE:
					realisedElement = NounPhraseHelper.realise(this, phrase);
					break;

				case VERB_PHRASE:
					realisedElement = VerbPhraseHelper.realise(this, phrase);
					break;

				case PREPOSITIONAL_PHRASE:
				case ADJECTIVE_PHRASE:
				case ADVERB_PHRASE:
					realisedElement = PhraseHelper.realise(this, phrase);
					break;

				default:
					realisedElement = phrase;
					break;
				}
			}
		}

		return realisedElement;
	}
}
