Coverage Report - com.mattunderscore.filter.contentnegotiation.variantsource.CachedVariantSource
 
Classes in this File Line Coverage Branch Coverage Complexity
CachedVariantSource
100%
9/9
100%
4/4
1.25
 
 1  
 /* Copyright © 2013 Matthew Champion
 2  
 All rights reserved.
 3  
 
 4  
 Redistribution and use in source and binary forms, with or without
 5  
 modification, are permitted provided that the following conditions are met:
 6  
  * Redistributions of source code must retain the above copyright
 7  
       notice, this list of conditions and the following disclaimer.
 8  
  * Redistributions in binary form must reproduce the above copyright
 9  
       notice, this list of conditions and the following disclaimer in the
 10  
       documentation and/or other materials provided with the distribution.
 11  
  * Neither the name of mattunderscore.com nor the
 12  
       names of its contributors may be used to endorse or promote products
 13  
       derived from this software without specific prior written permission.
 14  
 
 15  
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 16  
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 17  
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 18  
 DISCLAIMED. IN NO EVENT SHALL MATTHEW CHAMPION BE LIABLE FOR ANY
 19  
 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 20  
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 21  
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 22  
 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 23  
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 24  
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
 25  
 
 26  
 package com.mattunderscore.filter.contentnegotiation.variantsource;
 27  
 
 28  
 import java.util.Collections;
 29  
 import java.util.List;
 30  
 
 31  
 import com.mattunderscore.filter.contentnegotiation.parser.Variant;
 32  
 
 33  
 /**
 34  
  * Supports caching variant sources by providing a wrapper around them. This will only call the
 35  
  * underlying variant source when {@link #isCacheEmpty()} returns true. The cache starts empty and
 36  
  * can be cleared. The variant list this returns is unmodifiable.
 37  
  * 
 38  
  * @author Matt Champion
 39  
  * @since 0.2.0
 40  
  */
 41  
 public final class CachedVariantSource implements VariantSource
 42  
 {
 43  
     private final VariantSource source;
 44  
     private List<Variant> variants;
 45  
 
 46  
     /**
 47  
      * Constructs a cached version of the variant source.
 48  
      * 
 49  
      * @param source
 50  
      *            Underlying variant source
 51  
      * @since 0.2.0
 52  
      */
 53  
     public CachedVariantSource(VariantSource source)
 54  22
     {
 55  22
         this.source = source;
 56  22
     }
 57  
 
 58  
     @Override
 59  
     public List<Variant> getVariants() throws VariantSourceException
 60  
     {
 61  24
         if (isCacheEmpty())
 62  
         {
 63  22
             variants = Collections.unmodifiableList(source.getVariants());
 64  
         }
 65  24
         return variants;
 66  
     }
 67  
 
 68  
     /**
 69  
      * Returns true when there are no cached variants.
 70  
      * 
 71  
      * @return True when there are no cached variants.
 72  
      * @since 0.2.0
 73  
      */
 74  
     public boolean isCacheEmpty()
 75  
     {
 76  30
         return variants == null;
 77  
     }
 78  
 
 79  
     /**
 80  
      * Clears the cache of any variants. The next call to {@link #getVariants()} will cause the
 81  
      * underlying source to provide a new list.
 82  
      * 
 83  
      * @since 0.2.0
 84  
      */
 85  
     public void clearCache()
 86  
     {
 87  4
         variants = null;
 88  4
     }
 89  
 
 90  
 }