yang/yang-model-util/src/main/java/org/opendaylight/yangtools/yang/model/repo/util/InMemorySchemaSourceCache.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
   3  * This program and the accompanying materials are made available under the
   4  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   5  * and is available at http://www.eclipse.org/legal/epl-v10.html
   6  */
   7 package org.opendaylight.yangtools.yang.model.repo.util;
   8
   9 import com.google.common.base.Preconditions;
  10 import com.google.common.cache.Cache;
  11 import com.google.common.cache.CacheBuilder;
  12 import com.google.common.cache.RemovalListener;
  13 import com.google.common.cache.RemovalNotification;
  14 import com.google.common.util.concurrent.CheckedFuture;
  15 import com.google.common.util.concurrent.Futures;
  16
  17 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  18 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceException;
  19 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  20 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  21 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource.Costs;
  22 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  23 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  24
  25 public class InMemorySchemaSourceCache<T extends SchemaSourceRepresentation> extends AbstractSchemaSourceCache<T> {
  26     private static final class CacheEntry<T extends SchemaSourceRepresentation> {
  27         private final SchemaSourceRegistration<T> reg;
  28         private final T source;
  29
  30         public CacheEntry(final T source, final SchemaSourceRegistration<T> reg) {
  31             this.source = Preconditions.checkNotNull(source);
  32             this.reg = Preconditions.checkNotNull(reg);
  33         }
  34     }
  35
  36     private static final RemovalListener<SourceIdentifier, CacheEntry<?>> LISTENER = new RemovalListener<SourceIdentifier, CacheEntry<?>>() {
  37         @Override
  38         public void onRemoval(final RemovalNotification<SourceIdentifier, CacheEntry<?>> notification) {
  39             notification.getValue().reg.close();
  40         }
  41     };
  42
  43     private final Cache<SourceIdentifier, CacheEntry<T>> cache;
  44
  45     protected InMemorySchemaSourceCache(final SchemaSourceRegistry consumer, final Class<T> representation, final int maxSize) {
  46         super(consumer, representation, Costs.IMMEDIATE);
  47         cache = CacheBuilder.newBuilder().softValues().maximumSize(maxSize).removalListener(LISTENER).build();
  48     }
  49
  50     @Override
  51     public CheckedFuture<? extends T, SchemaSourceException> getSource(final SourceIdentifier sourceIdentifier) {
  52         final CacheEntry<T> present = cache.getIfPresent(sourceIdentifier);
  53         if (present != null) {
  54             return Futures.immediateCheckedFuture(present.source);
  55         }
  56
  57         return Futures.<T, SchemaSourceException>immediateFailedCheckedFuture(new MissingSchemaSourceException("Source not found", sourceIdentifier));
  58     }
  59
  60     @Override
  61     protected void offer(final T source) {
  62         final CacheEntry<T> present = cache.getIfPresent(source.getIdentifier());
  63         if (present == null) {
  64             final SchemaSourceRegistration<T> reg = register(source.getIdentifier());
  65             cache.put(source.getIdentifier(), new CacheEntry<T>(source, reg));
  66         }
  67     }
  68 }