gerrit.fd Code Review - hc2vpp.git/blob

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package io.fd.honeycomb.v3po.translate.v3po.util.cache;
  18
  19 import static com.google.common.base.Preconditions.checkNotNull;
  20
  21 import com.google.common.base.Optional;
  22 import io.fd.honeycomb.v3po.translate.ModificationCache;
  23 import io.fd.honeycomb.v3po.translate.v3po.util.cache.exceptions.check.DumpCheckFailedException;
  24 import io.fd.honeycomb.v3po.translate.v3po.util.cache.exceptions.execution.DumpExecutionFailedException;
  25 import io.fd.honeycomb.v3po.translate.v3po.util.cache.noop.NoopDumpPostProcessingFunction;
  26 import javax.annotation.Nonnull;
  27 import org.openvpp.jvpp.dto.JVppReplyDump;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30
  31 /**
  32  * Manager responsible for returning Data object dumps<br> either from cache or by invoking specified {@link
  33  * EntityDumpExecutor}
  34  */
  35 public final class DumpCacheManager<T extends JVppReplyDump, U> {
  36
  37     private static final Logger LOG = LoggerFactory.getLogger(DumpCacheManager.class);
  38
  39     private final EntityDumpExecutor<T, U> dumpExecutor;
  40     private final EntityDumpNonEmptyCheck<T> dumpNonEmptyCheck;
  41     private final EntityDumpPostProcessingFunction<T> postProcessor;
  42
  43     private DumpCacheManager(DumpCacheManagerBuilder builder) {
  44         this.dumpExecutor = builder.dumpExecutor;
  45         this.dumpNonEmptyCheck = builder.dumpNonEmptyCheck;
  46         this.postProcessor = builder.postProcessingFunction;
  47     }
  48
  49     /**
  50      * Returns {@link Optional<T>} of dump
  51      */
  52     public Optional<T> getDump(@Nonnull String entityKey, @Nonnull ModificationCache cache)
  53             throws DumpExecutionFailedException {
  54
  55         //this key binding to every log has its logic ,because every customizer have its own cache manager and if
  56         //there is need for debugging/fixing some complex call with a lot of data,you can get lost in those logs
  57         LOG.debug("Loading dump for KEY[{}]", entityKey);
  58
  59         T dump = (T) cache.get(entityKey);
  60
  61         if (dump == null) {
  62             LOG.debug("Dump for KEY[{}] not present in cache,invoking dump executor", entityKey);
  63
  64             dump = dumpExecutor.executeDump();
  65
  66             //this is not a critical exception, so its only logged here
  67             try {
  68                 dumpNonEmptyCheck.assertNotEmpty(dump);
  69             } catch (DumpCheckFailedException e) {
  70                 LOG.warn("Dump for KEY[{}] has been resolved as empty", entityKey, e);
  71                 return Optional.absent();
  72             }
  73
  74             //no need to check if post processor active,if wasnt set,default no-op will be used
  75             LOG.debug("Post-processing dump for KEY[{}]", entityKey);
  76             dump = postProcessor.apply(dump);
  77
  78             LOG.debug("Caching dump for KEY[{}]", entityKey);
  79             cache.put(entityKey, dump);
  80             return Optional.of(dump);
  81         } else {
  82             return Optional.of(dump);
  83         }
  84     }
  85
  86     public static final class DumpCacheManagerBuilder<T extends JVppReplyDump, U> {
  87
  88         private EntityDumpExecutor<T, U> dumpExecutor;
  89         private EntityDumpNonEmptyCheck<T> dumpNonEmptyCheck;
  90         private EntityDumpPostProcessingFunction<T> postProcessingFunction;
  91
  92         public DumpCacheManagerBuilder() {
  93             //for cases when user does not set specific post-processor
  94             postProcessingFunction = new NoopDumpPostProcessingFunction<T>();
  95         }
  96
  97         public DumpCacheManagerBuilder<T, U> withExecutor(@Nonnull EntityDumpExecutor<T, U> executor) {
  98             this.dumpExecutor = executor;
  99             return this;
 100         }
 101
 102         public DumpCacheManagerBuilder<T, U> withNonEmptyPredicate(@Nonnull EntityDumpNonEmptyCheck<T> check) {
 103             this.dumpNonEmptyCheck = check;
 104             return this;
 105         }
 106
 107         public DumpCacheManagerBuilder<T, U> withPostProcessingFunction(
 108                 EntityDumpPostProcessingFunction postProcessingFunction) {
 109             this.postProcessingFunction = postProcessingFunction;
 110             return this;
 111         }
 112
 113         public DumpCacheManager<T, U> build() {
 114             checkNotNull(dumpExecutor, "Dump executor cannot be null");
 115             checkNotNull(dumpNonEmptyCheck, "Dump verifier cannot be null");
 116             checkNotNull(postProcessingFunction,
 117                     "Dump post-processor cannot be null cannot be null, default implementation is used if its not set");
 118
 119             return new DumpCacheManager<T, U>(this);
 120         }
 121     }
 122 }
 123
 124