JSONVocabularyHelper.java

/**
 * Copyright 2008 The University of North Carolina at Chapel Hill
 *
 * 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 edu.unc.lib.dl.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.codehaus.jackson.map.ObjectMapper;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.Namespace;
import org.jdom2.filter.Filters;
import org.jdom2.xpath.XPathExpression;
import org.jdom2.xpath.XPathFactory;

import edu.unc.lib.dl.xml.VocabularyHelper;

/**
 * Vocabulary helper instantiated from a JSON array containing a list of vocabulary terms
 * 
 * @author bbpennel
 * @date Oct 7, 2015
 */
public class JSONVocabularyHelper implements VocabularyHelper {
	
	private List<String> values;
	
	private String vocabularyURI;
	private String invalidTermPrefix;
	
	private String selectorString;
	private XPathExpression<Element> selector;
	private Namespace[] namespaces;
	
	@Override
	public List<List<String>> getAuthoritativeForm(String term) {
		if (values.contains(term)) {
			return Arrays.asList(Arrays.asList(term));
		}
		return null;
	}

	@Override
	public List<List<String>> getAuthoritativeForms(Element docRoot) throws JDOMException {
		List<List<String>> terms = new ArrayList<>();
		
		List<Element> elements = selector.evaluate(docRoot);
		for (Element element : elements) {
			String value = element.getTextTrim();
			if (values.contains(value)) {
				terms.add(Arrays.asList(value));
			}
		}
		
		return terms;
	}

	@Override
	public Set<String> getInvalidTerms(Element docRoot) throws JDOMException {
		return generateInvalidTermsList(docRoot, false);
	}

	@Override
	public Set<String> getInvalidTermsWithPrefix(Element docRoot) throws JDOMException {
		return generateInvalidTermsList(docRoot, true);
	}
	
	private Set<String> generateInvalidTermsList(Element docRoot, boolean includePrefix) {
		Set<String> invalidTerms = new HashSet<>();
		
		List<Element> elements = selector.evaluate(docRoot);
		for (Element element : elements) {
			String value = element.getTextTrim();
			if (!values.contains(value)) {
				if (includePrefix) {
					invalidTerms.add(invalidTermPrefix + "|" + value);
				} else {
					invalidTerms.add(value);
				}
			}
		}
		
		return invalidTerms;
	}

	@Override
	public boolean updateDocumentTerms(Element docElement) throws JDOMException {
		return false;
	}

	@Override
	public Collection<String> getVocabularyTerms() {
		return values;
	}

	@Override
	public void setSelector(String selector) {
		XPathFactory xFactory = XPathFactory.instance();
		this.selector = xFactory.compile(selector, Filters.element(), null, namespaces);
		this.selectorString = selector;
	}
	
	@Override
	public void setSelectorNamespaces(Namespace[] namespaces) {
		this.namespaces = namespaces;
	}

	@Override
	public String getSelector() {
		return selectorString;
	}

	public void setInvalidTermPrefix(String prefix) {
		this.invalidTermPrefix = prefix;
	}
	
	@Override
	public String getInvalidTermPrefix() {
		return invalidTermPrefix;
	}

	@Override
	public String getVocabularyURI() {
		return this.vocabularyURI;
	}

	@Override
	public void setVocabularyURI(String vocabularyURI) {
		this.vocabularyURI = vocabularyURI;
	}

	@Override
	public void setContent(byte[] content) throws Exception {
		ObjectMapper mapper = new ObjectMapper();
		String[] values = mapper.readValue(content, String[].class);
		this.values = Arrays.asList(values);
	}
}