software/no.uio.ifi.refaktor/src/no/uio/ifi/refaktor/utils/CompilationUnitSoftReferencesCache.java

   1 package no.uio.ifi.refaktor.utils;
   2
   3 import java.lang.ref.SoftReference;
   4 import java.util.HashMap;
   5 import java.util.Map;
   6
   7 import org.eclipse.jdt.core.ICompilationUnit;
   8 import org.eclipse.jdt.core.dom.CompilationUnit;
   9
  10 public class CompilationUnitSoftReferencesCache implements CompilationUnitCache {
  11         private final Map<ICompilationUnit, SoftReference<CompilationUnit>> cache = new HashMap<ICompilationUnit, SoftReference<CompilationUnit>>();
  12         private final Map<ICompilationUnit, Long> modificationStamps = new HashMap<ICompilationUnit, Long>();
  13         private CompilationUnit tmpStrongCURef;
  14
  15         @Override
  16         public boolean contains(ICompilationUnit unit) {
  17                 SoftReference<CompilationUnit> softRef = cache.get(unit);
  18
  19                 if (softRef == null)
  20                         return false;
  21
  22                 tmpStrongCURef = softRef.get();
  23                 if (tmpStrongCURef != null) {
  24                         Long modificationStamp = modificationStamps.get(unit);
  25                         assert modificationStamp != null;
  26                         boolean modificationStampMatches = CacheCompilationUnitUtils.hasMatchingModificationStamp(unit, modificationStamp);
  27                         if (!modificationStampMatches)
  28                                 cleanCache(unit);
  29                         return modificationStampMatches;
  30                 }
  31
  32                 return false;
  33         }
  34
  35         private void cleanCache(ICompilationUnit unit) {
  36                 cache.remove(unit);
  37                 modificationStamps.remove(unit);
  38         }
  39
  40         @Override
  41         public CompilationUnit get(ICompilationUnit unit) {
  42                 try {
  43                         SoftReference<CompilationUnit> cachedRef = cache.get(unit);
  44                         CompilationUnit cachedCU = cachedRef.get();
  45                         assert cachedCU != null;
  46                         return cachedCU;
  47                 } finally {
  48                         tmpStrongCURef = null;
  49                 }
  50         }
  51
  52         @Override
  53         public void add(ICompilationUnit unit, CompilationUnit concreteCompilationUnit) {
  54                 cache.put(unit, new SoftReference<CompilationUnit>(concreteCompilationUnit));
  55                 modificationStamps.put(unit, CacheCompilationUnitUtils.getModificationStampOf(unit));
  56         }
  57
  58 }