Package org.eclipse.handly.model.impl.support

Class ElementCache

java.lang.Object
org.eclipse.handly.util.LruCache<K,V>
org.eclipse.handly.util.BoundedLruCache<IElement,Object>
org.eclipse.handly.model.impl.support.ElementCache
public class ElementCache extends BoundedLruCache<IElement,Object>
A bounded LRU cache of element handle/body relationships that is intended to be used in advanced implementations of IBodyCache. The cache is not strictly bounded, but can overflow if an entry is added when the cache is full but the current state of elements in the cache does not permit closing.

This implementation is not thread-safe. If multiple threads access the cache concurrently, it must be synchronized externally.

  • Constructor Details

    • ElementCache

      public ElementCache(int maxSize)
      Constructs an empty ElementCache with the given maximum size and a default load factor.
      Parameters:
      maxSize - the maximum size of the cache (the bound)
      Throws:
      IllegalArgumentException - if maxSize < 1

  • Method Details

    • getOverflow

      public int getOverflow()
      Returns the size of cache overflow.
      Returns:
      the size of cache overflow

    • getLoadFactor

      public double getLoadFactor()
      Returns the load factor of this cache. The load factor determines how much space is reclaimed when the cache overflows.
      Returns:
      the load factor of the cache (a value in the interval (0, 1])

    • setLoadFactor

      public void setLoadFactor(double loadFactor)
      Changes the load factor for this cache. The load factor determines how much space is reclaimed when the cache overflows.
      Parameters:
      loadFactor - a new value for load factor
      Throws:
      IllegalArgumentException - if loadFactor <= 0 or loadFactor > 1

    • ensureMaxSize

      public void ensureMaxSize(int childCount, IElement parent)
      Ensures that there is enough room for adding the given number of child elements. If the maximum size of the cache must be increased, records the parent element that needed the new maximum size.
      Parameters:
      childCount - the number of child elements (>= 0)
      parent - the parent element (not null)

    • resetMaxSize

      public void resetMaxSize(int maxSize, IElement parent)
      If the given parent element was the one that increased the maximum size of this cache in ensureMaxSize, resets the maximum size of the cache to the given value.
      Parameters:
      maxSize - a new value for maximum size of the cache (> 0)
      parent - the parent element (not null)

    • toString

      public String toString()
      Overrides:
      toString in class LruCache<IElement,Object>

    • makeSpace

      protected void makeSpace(int sizeNeeded)
      Description copied from class: BoundedLruCache
      Attempts to evict stale entries to make space as requested. Follows the access order, starting from the least recently used entry.
      Overrides:
      makeSpace in class BoundedLruCache<IElement,Object>
      Parameters:
      sizeNeeded - the requested space (>= 0)

    • evict

      protected void evict(LruCache.Entry<IElement,Object> entry)
      Attempts to evict an existing entry from this cache in response to request to makeSpace. It is permitted for this method to remove other cache entries along with the given entry or, if the given entry cannot currently be evicted, retain it in the cache.

      This implementation invokes ((IElementImplExtension)entry.key).close_ (of(CLOSE_HINT, CACHE_OVERFLOW)).

      Overrides:
      evict in class BoundedLruCache<IElement,Object>
      Parameters:
      entry - an existing entry