/*
 * Ivory: A Hadoop toolkit for web-scale information retrieval
 *
 * 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 ivory.smrf.model.importance;

import ivory.core.ConfigurationException;
import ivory.core.util.XMLTools;
import ivory.smrf.model.Clique;

import org.w3c.dom.Node;

import com.google.common.base.Preconditions;

/**
 * @author Don Metzler
 */
public abstract class ConceptImportanceModel {

  // Configures the model.
  public abstract void configure(Node model) throws ConfigurationException;

  // Returns the importance of the concept.
  public abstract float getConceptWeight(String concept);

  // Returns the importance of the concepts currently associated with a clique.
  public abstract float getCliqueWeight(Clique c);

  @SuppressWarnings("unchecked")
  public static ConceptImportanceModel get(Node model) throws ConfigurationException {
    Preconditions.checkNotNull(model);

    // Get model type.
    String modelType = XMLTools.getAttributeValue(model, "type", null);
    if (modelType == null) {
      throw new ConfigurationException("Model type must be specified!");
    }

    // Dynamically construct importance model.
    ConceptImportanceModel importanceModel = null;
    try {
      Class<? extends ConceptImportanceModel> clz =
        (Class<? extends ConceptImportanceModel>) Class.forName(modelType);
      importanceModel = clz.newInstance();
      importanceModel.configure(model);
    } catch (Exception e) {
      throw new ConfigurationException("Error instantiating ConceptImportanceModel! " + e);
    }

    return importanceModel;
  }
}