class PEROBS::PersistentObjectCacheLine
Constants
- WATERMARK
This defines the minimum size of the cache line. If it is too large, the time to find an entry will grow too much. If it is too small the number of cache lines will be too large and create more store overhead. By running benchmarks it turned out that 8 is a pretty good compromise.
Public Class Methods
new()
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# File lib/perobs/PersistentObjectCacheLine.rb, line 43 def initialize @entries = [] end
Public Instance Methods
delete(uid)
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Delete the entry that matches the given UID @param uid [Integer]
# File lib/perobs/PersistentObjectCacheLine.rb, line 77 def delete(uid) @entries.delete_if { |e| e.obj.uid == uid } end
flush(now)
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Save all modified entries and delete all but the most recently added.
# File lib/perobs/PersistentObjectCacheLine.rb, line 82 def flush(now) if now || @entries.length > WATERMARK @entries.each do |e| if e.modified e.obj.save e.modified = false end end # Delete all but the first WATERMARK entry. @entries = @entries[0..WATERMARK - 1] if @entries.length > WATERMARK end end
get(uid)
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# File lib/perobs/PersistentObjectCacheLine.rb, line 63 def get(uid) if (index = @entries.find_index{ |e| e.obj.uid == uid }) if index > 0 # Move the entry to the front. @entries.unshift(@entries.delete_at(index)) end @entries.first else nil end end
insert(object, modified)
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# File lib/perobs/PersistentObjectCacheLine.rb, line 47 def insert(object, modified) if (index = @entries.find_index{ |e| e.obj.uid == object.uid }) # We have found and removed an existing entry for this particular # object. If the modified flag is set, ensure that the entry has it # set as well. entry = @entries.delete_at(index) entry.modified = true if modified && !entry.modified else # There is no existing entry for this object. Create a new one. entry = Entry.new(object, modified) end # Insert the entry at the beginning of the line. @entries.unshift(entry) end