code: package it.unibz.inf.ontop.model.term.functionsymbol;
  
  /*
   * #%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%
   */
  
  /**
  * The Predicate class currently represents (1) first-order predicts, (2) function symbols, and
   * (3) logical operators (e.g. join, left join)
   *
   */
  public interface Predicate {
      
  	/**
  	 * Get the name of the predicate. In practice, the predicate name is
  	 * constructed as a URI to indicate a unique resource.
  	 * 
  	 * @return the resource identifier (URI).
  	 */
      String getName();
  
  	/**
  	 * Get the number of elements of the predicate.
  	 * 
  	 * @return an integer number.
  	 */
      int getArity();
  }
  