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.annotations.Beta;
  10 import com.google.common.base.Preconditions;
  11 import com.google.common.cache.Cache;
  12 import com.google.common.cache.CacheBuilder;
  13 import com.google.common.cache.RemovalListener;
  14 import com.google.common.cache.RemovalNotification;
  15 import com.google.common.util.concurrent.CheckedFuture;
  16 import com.google.common.util.concurrent.Futures;
  17
  18 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  19 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceException;
  20 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  21 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  22 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource.Costs;
  23 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  24 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  25
  26 @Beta
  27 public class InMemorySchemaSourceCache<T extends SchemaSourceRepresentation> extends AbstractSchemaSourceCache<T> {
  28     private static final class CacheEntry<T extends SchemaSourceRepresentation> {
  29         private final SchemaSourceRegistration<T> reg;
  30         private final T source;
  31
  32         public CacheEntry(final T source, final SchemaSourceRegistration<T> reg) {
  33             this.source = Preconditions.checkNotNull(source);
  34             this.reg = Preconditions.checkNotNull(reg);
  35         }
  36     }
  37
  38     private static final RemovalListener<SourceIdentifier, CacheEntry<?>> LISTENER = new RemovalListener<SourceIdentifier, CacheEntry<?>>() {
  39         @Override
  40         public void onRemoval(final RemovalNotification<SourceIdentifier, CacheEntry<?>> notification) {
  41             notification.getValue().reg.close();
  42         }
  43     };
  44
  45     private final Cache<SourceIdentifier, CacheEntry<T>> cache;
  46
  47     protected InMemorySchemaSourceCache(final SchemaSourceRegistry consumer, final Class<T> representation, final CacheBuilder<Object, Object> builder) {
  48         super(consumer, representation, Costs.IMMEDIATE);
  49         cache = builder.removalListener(LISTENER).build();
  50     }
  51
  52     public static <R extends SchemaSourceRepresentation> InMemorySchemaSourceCache<R> createSoftCache(final SchemaSourceRegistry consumer, final Class<R> representation) {
  53         return new InMemorySchemaSourceCache<>(consumer, representation, CacheBuilder.newBuilder().softValues());
  54     }
  55
  56     @Override
  57     public CheckedFuture<? extends T, SchemaSourceException> getSource(final SourceIdentifier sourceIdentifier) {
  58         final CacheEntry<T> present = cache.getIfPresent(sourceIdentifier);
  59         if (present != null) {
  60             return Futures.immediateCheckedFuture(present.source);
  61         }
  62
  63         return Futures.<T, SchemaSourceException>immediateFailedCheckedFuture(new MissingSchemaSourceException("Source not found", sourceIdentifier));
  64     }
  65
  66     @Override
  67     protected void offer(final T source) {
  68         final CacheEntry<T> present = cache.getIfPresent(source.getIdentifier());
  69         if (present == null) {
  70             final SchemaSourceRegistration<T> reg = register(source.getIdentifier());
  71             cache.put(source.getIdentifier(), new CacheEntry<T>(source, reg));
  72         }
  73     }
  74 }