/**
 *    Copyright 2011 meltmedia
 *
 *    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.xchain.framework.util;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * Signals that a circular dependency was found.
 *
 * @author Christian Trimble
 * @author Devon Tackett
 */
public class DependencyCycleException
  extends Exception
{
  protected Map cycle;

  public DependencyCycleException(String message, Map cycle)
  {
    super(createMessage( message, cycle ));
    this.cycle = cycle;
  }

  public Map getCycle()
  {
    return this.cycle;
  }

  public static String createMessage( String message, Map cycle)
  {
    StringBuffer sb = new StringBuffer();
    sb.append(message).append("\n");
    Iterator cycleIterator = cycle.entrySet().iterator();
    while( cycleIterator.hasNext() ) {
      Map.Entry cycleEntry = (Map.Entry)cycleIterator.next();
      sb.append("  ");
      sb.append(cycleEntry.getKey());
      sb.append(" dependends on ( ");
      Iterator dependencyIterator = ((Set)cycleEntry.getValue()).iterator();
      while( dependencyIterator.hasNext() ) {
        sb.append(dependencyIterator.next());
        if( dependencyIterator.hasNext() ) {
          sb.append(", ");
        }
      }
      sb.append(" )");
      if( cycleIterator.hasNext() ) {
        sb.append("\n");
      }
    }
    return sb.toString();
  }
}