/*
 * Copyright 2006 Werner Guttmann
 *
 * 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 org.exolab.castor.builder.conflictresolution;

import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Registry for {@link ClassNameCRStrategy} implementations obtained from the Castor builder
 * properties file.
 *
 * @author <a href="mailto:werner DOT guttmann @gmx DOT net">Werner Guttmann</a>
 * @version $Revision: 5951 $ $Date: 2006-04-08 08:58:10 -0600 (Sat, 08 Apr 2006) $
 * @since 1.1
 */
public final class ClassNameCRStrategyRegistry {
  // --------------------------------------------------------------------------

  /**
   * The <a href="http://jakarta.apache.org/commons/logging/">Jakarta Commons Logging</a> instance
   * used for all logging.
   */
  private static final Log LOG = LogFactory.getLog(ClassNameCRStrategyRegistry.class);

  /**
   * Association between name of {@link ClassNameCRStrategy} implementation and
   * {@link ClassNameCRStrategy} instance.
   */
  private Map<String, ClassNameCRStrategy> _strategies = new HashMap<String, ClassNameCRStrategy>();

  // --------------------------------------------------------------------------

  /**
   * Construct an instance of {@link ClassNameCRStrategyRegistry} that loads the
   * {@link ClassNameCRStrategy} implementations specified in the given BuilderConfiguration.
   *
   * @param enlistedNameConflictStrategies The BuilderConfiguration.
   */
  public ClassNameCRStrategyRegistry(final String enlistedNameConflictStrategies) {
    StringTokenizer tokenizer = new StringTokenizer(enlistedNameConflictStrategies, ", ");
    ClassLoader loader = ClassNameCRStrategyRegistry.class.getClassLoader();
    while (tokenizer.hasMoreTokens()) {
      String classname = tokenizer.nextToken();
      try {
        Class<?> cls = loader.loadClass(classname);
        Object obj = cls.newInstance();
        ClassNameCRStrategy strategy = (ClassNameCRStrategy) obj;
        _strategies.put(strategy.getName(), strategy);
      } catch (Exception except) {
        LOG.error("The ClassNameConflictResolutionStrategy " + classname + " "
            + "specified in the Castor builder properties file could not " + "be instantiated.");
      }
    }
  }

  // --------------------------------------------------------------------------

  /**
   * Returns the names of all the configured {@link ClassNameCRStrategy} implementations. A
   * {@link ClassNameCRStrategy} instance can be obtained by the
   * {@link #getClassNameConflictResolutionStrategy} method.
   *
   * @return Names of {@link ClassNameCRStrategy} implementations
   */
  public String[] getClassNameConflictResolutionStrategyNames() {
    String[] names = new String[_strategies.size()];
    return _strategies.keySet().toArray(names);
  }

  /**
   * Returns a {@link ClassNameCRStrategy} with the specified name. Returns null if the named
   * strategy is not supported.
   *
   * @param name The name of the ClassNameConflictResolutionStrategy.
   * @return The TransactionManagerFactory or null if none exists.
   */
  public ClassNameCRStrategy getClassNameConflictResolutionStrategy(final String name) {
    Object factory = _strategies.get(name);
    if (factory == null) {
      String msg = "The ClassNameConflictResolutionStrategy '" + name + "' "
          + "does not exist in the Castor builder properties file "
          + "and is therefore not supported.";
      LOG.error(msg);
      throw new IllegalArgumentException(msg);
    }
    return (ClassNameCRStrategy) factory;
  }

}
