net.sf.javagimmicks.concurrent.locks.DefaultLockRegistry Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of gimmicks Show documentation
Utility classes, APIs and tools for Java
There is a newer version: 0.99-alpha1
package net.sf.javagimmicks.concurrent.locks;

import java.io.Serializable;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.TreeMap;

import net.sf.javagimmicks.util.Supplier;

class DefaultLockRegistry implements LockRegistry, Serializable
{
   private static final long serialVersionUID = -785304313135882910L;

   private static final Supplier> HASHSET_SHARED_COLLECTION_SUPPLIER = new HashSetSharedCollectionSupplier();

   public static  DefaultLockRegistry createHashBasedInstance()
   {
      return new DefaultLockRegistry(new HashMap(), new HashMap>(),
            HASHSET_SHARED_COLLECTION_SUPPLIER);
   }

   public static  DefaultLockRegistry createTreeBasedInstance()
   {
      return new DefaultLockRegistry(new TreeMap(), new TreeMap>(),
            HASHSET_SHARED_COLLECTION_SUPPLIER);
   }

   protected final Map _exRegistry;
   protected final Map> _shRegistry;
   protected final Supplier> _shCollectionSupplier;

   public DefaultLockRegistry(final Map exRegistry, final Map> shRegistry,
         final Supplier> sharedCollectionFactory)
   {
      _exRegistry = exRegistry;
      _shRegistry = shRegistry;
      _shCollectionSupplier = sharedCollectionFactory;
   }

   @Override
   public boolean isSharedFree(final Collection resources)
   {
      for (final K resource : resources)
      {
         if (_shRegistry.containsKey(resource))
         {
            return false;
         }
      }

      return true;
   }

   @Override
   public void registerShared(final Collection resources)
   {
      final Thread currentThread = Thread.currentThread();

      for (final K resource : resources)
      {
         Collection threadsForResource = _shRegistry.get(resource);
         if (threadsForResource == null)
         {
            threadsForResource = _shCollectionSupplier.get();
            _shRegistry.put(resource, threadsForResource);
         }

         threadsForResource.add(currentThread);
      }
   }

   @Override
   public void unregisterShared(final Collection resources)
   {
      final Thread currentThread = Thread.currentThread();

      for (final K resource : resources)
      {
         final Collection threadsForResource = _shRegistry.get(resource);
         if (threadsForResource == null)
         {
            continue;
         }

         threadsForResource.remove(currentThread);

         if (threadsForResource.isEmpty())
         {
            _shRegistry.remove(resource);
         }
      }
   }

   @Override
   public boolean isExclusiveFree(final Collection resources)
   {
      for (final K resource : resources)
      {
         if (_exRegistry.containsKey(resource))
         {
            return false;
         }
      }

      return true;
   }

   @Override
   public void registerExclusive(final Collection resources)
   {
      final Thread currentThread = Thread.currentThread();

      for (final K resource : resources)
      {
         _exRegistry.put(resource, currentThread);
      }
   }

   @Override
   public void unregisterExclusive(final Collection resources)
   {
      for (final K resource : resources)
      {
         _exRegistry.remove(resource);
      }
   }

   private static final class HashSetSharedCollectionSupplier implements Supplier>, Serializable
   {
      private static final long serialVersionUID = 3613642441786733902L;

      @Override
      public Collection get()
      {
         return new HashSet();
      }
   }
}