package org.opentrafficsim.kpi.sampling.meta;
   
   import java.util.HashMap;
   import java.util.Iterator;
   import java.util.Map;
   import java.util.Map.Entry;
   import java.util.Set;
   
   import org.djutils.exceptions.Throw;
  import org.djutils.immutablecollections.ImmutableIterator;
  
  /**
   * Collection of objects, one object per meta data type included.
   * <p>
   * Copyright (c) 2013-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="http://opentrafficsim.org/node/13">OpenTrafficSim License</a>.
   * <p>
   * @version $Revision$, $LastChangedDate$, by $Author$, initial version Sep 25, 2016 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   * @author <a href="http://www.transport.citg.tudelft.nl">Wouter Schakel</a>
   */
  public class MetaData
  {
  
      /** Meta data. */
      private final Map<MetaDataType<?>, Object> metaDataMap = new HashMap<>();
  
      /**
       * Default constructor.
       */
      public MetaData()
      {
          //
      }
  
      /**
       * @param metaData MetaData; meta data to copy into new meta data
       */
      public MetaData(final MetaData metaData)
      {
          Throw.whenNull(metaData, "Meta data may not be null.");
          for (MetaDataType<?> metaDataType : metaData.metaDataMap.keySet())
          {
              this.metaDataMap.put(metaDataType, metaData.metaDataMap.get(metaDataType));
          }
      }
  
      /**
       * @param metaDataType MetaDataType&lt;T&gt;; meta data type
       * @param <T> class of meta data
       * @param value T; value of meta data
       */
      public final <T> void put(final MetaDataType<T> metaDataType, final T value)
      {
          Throw.whenNull(metaDataType, "Meta data type may not be null.");
          this.metaDataMap.put(metaDataType, value);
      }
  
      /**
       * @param metaDataType MetaDataType&lt;?&gt;; meta data type
       * @return whether the trajectory contains the meta data of give type
       */
      public final boolean contains(final MetaDataType<?> metaDataType)
      {
          return this.metaDataMap.containsKey(metaDataType);
      }
  
      /**
       * @param metaDataType MetaDataType&lt;T&gt;; meta data type
       * @param <T> class of meta data
       * @return value of meta data
       */
      @SuppressWarnings("unchecked")
      public final <T> T get(final MetaDataType<T> metaDataType)
      {
          return (T) this.metaDataMap.get(metaDataType);
      }
  
      /**
       * @return set of meta data types
       */
      public final Set<MetaDataType<?>> getMetaDataTypes()
      {
          return this.metaDataMap.keySet();
      }
  
      /**
       * @return number of meta data entries
       */
      public final int size()
      {
          return this.metaDataMap.size();
      }
  
      /**
       * @return iterator over meta data entries, removal is not allowed
       */
      public final Iterator<Entry<MetaDataType<?>, Object>> getMetaDataIterator()
     {
         return new ImmutableIterator<>(this.metaDataMap.entrySet().iterator());
     }
 
     /** {@inheritDoc} */
     @Override
     public final int hashCode()
     {
         final int prime = 31;
         int result = 1;
         result = prime * result + ((this.metaDataMap == null) ? 0 : this.metaDataMap.hashCode());
         return result;
     }
 
     /** {@inheritDoc} */
     @Override
     public final boolean equals(final Object obj)
     {
         if (this == obj)
         {
             return true;
         }
         if (obj == null)
         {
             return false;
         }
         if (getClass() != obj.getClass())
         {
             return false;
         }
         MetaData other = (MetaData) obj;
         if (this.metaDataMap == null)
         {
             if (other.metaDataMap != null)
             {
                 return false;
             }
         }
         else if (!this.metaDataMap.equals(other.metaDataMap))
         {
             return false;
         }
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public final String toString()
     {
         return "MetaData [" + this.metaDataMap + "]";
     }
 
 }