code: package it.unibz.inf.ontop.spec.mapping.impl;
  
  /*
   * #%L
   * ontop-obdalib-core
   * %%
   * Copyright (C) 2009 - 2014 Free University of Bozen-Bolzano
   * %%
   * 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.
   * #L%
   */
  
  import com.google.common.collect.ImmutableList;
  import it.unibz.inf.ontop.exception.InvalidPrefixWritingException;
  import it.unibz.inf.ontop.spec.mapping.PrefixManager;
  import it.unibz.inf.ontop.utils.ImmutableCollectors;
  
  import java.util.*;
  
  public abstract class AbstractPrefixManager implements PrefixManager {
  
  	protected abstract Optional<String> getIriDefinition(String prefix);
  	
  	protected abstract List<Map.Entry<String, String>> getOrderedMap();
  	
  	protected static List<Map.Entry<String, String>> orderMap(Map<String, String> map) {
  		Comparator<Map.Entry<String, String>> comparator =
  				Map.Entry.<String, String>comparingByValue()
  						.reversed()
  						.thenComparing(Map.Entry.comparingByKey());;
  		return map.entrySet().stream()
  				.sorted(comparator)
  				.collect(ImmutableCollectors.toList());
  	}
  
  	@Override
  	public String getShortForm(String stringIri) {
  		// Clean the IRI string from <...> signs, if they exist.
  		// <http://www.example.org/library#Book> --> http://www.example.org/library#Book
  		String fullIri = stringIri.startsWith("<") && stringIri.endsWith(">")
  				? stringIri.substring(1, stringIri.length() - 1)
  				: stringIri;
  		
  		// Check if the URI string has a matched prefix
  		for (Map.Entry<String, String> e : getOrderedMap()) {
  			String iri = e.getValue();
  			if (fullIri.startsWith(iri)) {
  				// Replace the IRI with the corresponding prefix.
  				return e.getKey() + fullIri.substring(iri.length());
  			}
  		}
  		return stringIri; // return the original IRI if no prefix definition was found
  	}
  	
  	@Override
  	public String getExpandForm(String prefixedName) {
  		int index = prefixedName.indexOf(":") + 1;
  		if (index == 0)
  			throw new InvalidPrefixWritingException();
  
  		// extract the whole prefix, e.g., "ex:Book" --> "ex:"
  		String prefix = prefixedName.substring(0, index);
  		String iri = getIriDefinition(prefix)
  				.orElseThrow(() -> new InvalidPrefixWritingException("The prefix name is unknown: " + prefix));
  
  		return iri + prefixedName.substring(index);
  	}
  	
  	@Override
  	public String getDefaultIriPrefix() {
  		return getIriDefinition(DEFAULT_PREFIX)
  				.orElseThrow(() -> new InvalidPrefixWritingException("No default prefix"));
  	}
  }
  