Coverage Report - org.mule.util.store.InMemoryObjectStore
 
Classes in this File Line Coverage Branch Coverage Complexity
InMemoryObjectStore
0%
0/69
0%
0/36
0
InMemoryObjectStore$StoredObject
0%
0/21
0%
0/8
0
 
 1  
 /*
 2  
  * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 3  
  * The software in this package is published under the terms of the CPAL v1.0
 4  
  * license, a copy of which has been included with this distribution in the
 5  
  * LICENSE.txt file.
 6  
  */
 7  
 package org.mule.util.store;
 8  
 
 9  
 import org.mule.api.store.ObjectAlreadyExistsException;
 10  
 import org.mule.api.store.ObjectDoesNotExistException;
 11  
 import org.mule.api.store.ObjectStoreException;
 12  
 import org.mule.config.i18n.CoreMessages;
 13  
 
 14  
 import java.io.Serializable;
 15  
 import java.util.Iterator;
 16  
 import java.util.Map;
 17  
 
 18  
 import edu.emory.mathcs.backport.java.util.concurrent.ConcurrentSkipListMap;
 19  
 import edu.emory.mathcs.backport.java.util.concurrent.TimeUnit;
 20  
 
 21  
 /**
 22  
  * <code>InMemoryObjectStore</code> implements an optionally bounded
 23  
  * in-memory store for message IDs with periodic expiry of old entries. The bounded size
 24  
  * is a <i>soft</i> limit and only enforced periodically by the expiry process; this
 25  
  * means that the store may temporarily exceed its maximum size between expiry runs, but
 26  
  * will eventually shrink to its configured size.
 27  
  */
 28  
 public class InMemoryObjectStore<T extends Serializable> extends AbstractMonitoredObjectStore<T>
 29  
 {
 30  
     protected ConcurrentSkipListMap/*<Long, StoredObject>*/ store;
 31  
 
 32  
     public InMemoryObjectStore()
 33  0
     {
 34  0
         this.store = new ConcurrentSkipListMap();
 35  0
     }
 36  
 
 37  
     /**
 38  
      * {@inheritDoc}
 39  
      */
 40  
     public boolean contains(Serializable key) throws ObjectStoreException
 41  
     {
 42  0
         if (key == null)
 43  
         {
 44  0
             throw new ObjectStoreException(CoreMessages.objectIsNull("id"));
 45  
         }
 46  
 
 47  0
         synchronized (store)
 48  
         {
 49  0
             return store.values().contains(new StoredObject<T>(key, null));
 50  0
         }
 51  
     }
 52  
 
 53  
     /**
 54  
      * {@inheritDoc}
 55  
      */
 56  
     public void store(Serializable id, T value) throws ObjectStoreException
 57  
     {
 58  0
         if (id == null)
 59  
         {
 60  0
             throw new ObjectStoreException(CoreMessages.objectIsNull("id"));
 61  
         }
 62  
 
 63  
         // this block is unfortunately necessary to counter a possible race condition
 64  
         // between multiple nonatomic calls to containsObject/storeObject
 65  0
         StoredObject<T> obj = new StoredObject<T>(id, value);
 66  0
         synchronized (store)
 67  
         {
 68  0
             if (store.values().contains(obj))
 69  
             {
 70  0
                 throw new ObjectAlreadyExistsException();
 71  
             }
 72  
 
 73  0
             boolean written = false;
 74  0
             while (!written)
 75  
             {
 76  0
                 Long key = Long.valueOf(System.nanoTime());
 77  0
                 written = (store.put(key, obj) == null);
 78  0
             }
 79  0
         }
 80  0
     }
 81  
 
 82  
     /**
 83  
      * {@inheritDoc}
 84  
      */
 85  
     @SuppressWarnings("unchecked")
 86  
     public T retrieve(Serializable key) throws ObjectStoreException
 87  
     {
 88  0
         synchronized (store)
 89  
         {
 90  0
             Map.Entry<?, ?> entry = findEntry(key);
 91  0
             if (entry != null)
 92  
             {
 93  0
                 StoredObject object = (StoredObject) entry.getValue();
 94  0
                 return (T)object.getItem();
 95  
             }
 96  0
         }
 97  
         
 98  0
         throw new ObjectDoesNotExistException(CoreMessages.objectNotFound(key));
 99  
     }
 100  
 
 101  
     @SuppressWarnings("unchecked")
 102  
     private Map.Entry<?, ?> findEntry(Serializable key)
 103  
     {
 104  0
         Iterator<?> entryIterator = store.entrySet().iterator();
 105  0
         while (entryIterator.hasNext())
 106  
         {
 107  0
             Map.Entry<?, ?> entry = (Map.Entry<?, ?>) entryIterator.next();
 108  
             
 109  0
             StoredObject object = (StoredObject) entry.getValue();
 110  0
             if (object.getId().equals(key))
 111  
             {
 112  0
                 return entry;
 113  
             }
 114  0
         }
 115  0
         return null;
 116  
     }
 117  
 
 118  
     @SuppressWarnings("unchecked")
 119  
     public T remove(Serializable key) throws ObjectStoreException
 120  
     {
 121  0
         synchronized (store)
 122  
         {
 123  0
             Map.Entry<?, ?> entry = findEntry(key);
 124  0
             if (entry != null)
 125  
             {
 126  0
                 StoredObject removedObject = (StoredObject) store.remove(entry.getKey());
 127  0
                 return (T)removedObject.getItem();
 128  
             }
 129  0
         }
 130  
         
 131  0
         throw new ObjectDoesNotExistException(CoreMessages.objectNotFound(key));
 132  
     }
 133  
     
 134  
     @Override
 135  
     public void expire()
 136  
     {
 137  
         // this is not guaranteed to be precise, but we don't mind
 138  0
         int currentSize = store.size();
 139  
         
 140  
         // first trim to maxSize if necessary
 141  0
         currentSize = trimToMaxSize(currentSize);
 142  
 
 143  
         // expire further if entry TTLs are enabled
 144  0
         if ((entryTTL > 0) && (currentSize != 0))
 145  
         {
 146  0
             final long now = System.nanoTime();
 147  0
             int expiredEntries = 0;
 148  
             Map.Entry<?, ?> oldestEntry;
 149  
 
 150  
             purge:
 151  0
             while ((oldestEntry = store.firstEntry()) != null)
 152  
             {
 153  0
                 Long oldestKey = (Long) oldestEntry.getKey();
 154  0
                 long oldestKeyValue = oldestKey.longValue();
 155  
 
 156  0
                 if (TimeUnit.NANOSECONDS.toMillis(now - oldestKeyValue) >= entryTTL)
 157  
                 {
 158  0
                     store.remove(oldestKey);
 159  0
                     expiredEntries++;
 160  
                 }
 161  
                 else
 162  
                 {
 163  
                     break purge;
 164  
                 }
 165  0
             }
 166  
 
 167  0
             if (logger.isDebugEnabled())
 168  
             {
 169  0
                 logger.debug("Expired " + expiredEntries + " old entries");
 170  
             }
 171  
         }
 172  0
     }
 173  
 
 174  
     private int trimToMaxSize(int currentSize)
 175  
     {
 176  0
         if (maxEntries < 0)
 177  
         {
 178  0
             return currentSize;
 179  
         }
 180  
         
 181  0
         int excess = (currentSize - maxEntries);
 182  0
         if (excess > 0)
 183  
         {
 184  0
             while (currentSize > maxEntries)
 185  
             {
 186  0
                 store.pollFirstEntry();
 187  0
                 currentSize--;
 188  
             }
 189  
 
 190  0
             if (logger.isDebugEnabled())
 191  
             {
 192  0
                 logger.debug("Expired " + excess + " excess entries");
 193  
             }
 194  
         }
 195  0
         return currentSize;
 196  
     }
 197  
 
 198  
     @Override
 199  
     public String toString()
 200  
     {
 201  0
         return getClass().getSimpleName() + " " + store;
 202  
     }
 203  
 
 204  
     /**
 205  
      * Represents the object stored in the store. This class holds the Object itslef and its ID.
 206  
      */
 207  
     protected static class StoredObject<T>
 208  
     {
 209  
         private Serializable id;
 210  
         private T item;
 211  
 
 212  
         public StoredObject(Serializable id, T item)
 213  0
         {
 214  0
             this.id = id;
 215  0
             this.item = item;
 216  0
         }
 217  
 
 218  
         public Serializable getId()
 219  
         {
 220  0
             return id;
 221  
         }
 222  
 
 223  
         public T getItem()
 224  
         {
 225  0
             return item;
 226  
         }
 227  
 
 228  
         @Override
 229  
         @SuppressWarnings("unchecked")
 230  
         public boolean equals(Object o)
 231  
         {
 232  0
             if (this == o)
 233  
             {
 234  0
                 return true;
 235  
             }
 236  0
             if (o == null || getClass() != o.getClass())
 237  
             {
 238  0
                 return false;
 239  
             }
 240  
 
 241  0
             StoredObject that = (StoredObject) o;
 242  
 
 243  0
             if (!id.equals(that.id))
 244  
             {
 245  0
                 return false;
 246  
             }
 247  
 
 248  0
             return true;
 249  
         }
 250  
 
 251  
         @Override
 252  
         public int hashCode()
 253  
         {
 254  0
             return id.hashCode();
 255  
         }
 256  
 
 257  
         @Override
 258  
         public String toString()
 259  
         {
 260  0
             final StringBuffer sb = new StringBuffer();
 261  0
             sb.append("StoredObject");
 262  0
             sb.append("{id='").append(id).append('\'');
 263  0
             sb.append(", item=").append(item);
 264  0
             sb.append('}');
 265  0
             return sb.toString();
 266  
         }
 267  
     }
 268  
 }