Class: PEROBS::Hash
- Inherits:
-
ObjectBase
- Object
- ObjectBase
- PEROBS::Hash
- Defined in:
- lib/perobs/Hash.rb
Overview
A Hash that is transparently persisted in the back-end storage. It is very similar to the Ruby built-in Hash class but has some additional limitations. The hash key must always be a String.
The implementation is largely a proxy around the standard Hash class. But all mutating methods must be re-implemented to convert PEROBS::Objects to POXReference objects and to register the object as modified with the cache. However, it is not designed for large data sets as it always reads and writes the full data set for every access (unless it is cached). For data sets that could have more than a few hundred entries BigHash is the recommended alternative.
We explicitely don’t support Hash::store() as it conflicts with ObjectBase::store() method to access the store.
Constant Summary
Constants inherited from ObjectBase
Instance Attribute Summary
Attributes inherited from ObjectBase
Instance Method Summary collapse
-
#[]=(key, value) ⇒ Object
Proxy for assignment method.
-
#_delete_reference_to_id(id) ⇒ Object
This method should only be used during store repair operations.
-
#_deserialize(data) ⇒ Object
Restore the persistent data from a single data structure.
-
#_referenced_object_ids ⇒ Array of Integer
Return a list of all object IDs of all persistend objects that this Hash is referencing.
-
#default=(value) ⇒ Object
Proxy for default= method.
-
#initialize(p, default = nil, &block) ⇒ Hash
constructor
New PEROBS objects must always be created by calling # Store.new().
-
#inspect ⇒ String
Textual dump for debugging purposes.
Methods inherited from ObjectBase
#==, #_check_assignment_value, _finalize, #_initialize, #_restore, #_stash, #_sync, #_transfer, read, #restore
Constructor Details
#initialize(p, default = nil, &block) ⇒ Hash
New PEROBS objects must always be created by calling # Store.new(). PEROBS users should never call this method or equivalents of derived methods directly.
112 113 114 115 116 117 118 119 120 121 122 123 |
# File 'lib/perobs/Hash.rb', line 112 def initialize(p, default = nil, &block) super(p) _check_assignment_value(default) if block_given? @data = ::Hash.new(&block) else @data = ::Hash.new(default) end # Ensure that the newly created object will be pushed into the database. @store.cache.cache_write(self) end |
Instance Method Details
#[]=(key, value) ⇒ Object
Proxy for assignment method.
126 127 128 129 130 |
# File 'lib/perobs/Hash.rb', line 126 def []=(key, value) _check_assignment_value(value) @store.cache.cache_write(self) @data[key] = value end |
#_delete_reference_to_id(id) ⇒ Object
This method should only be used during store repair operations. It will delete all referenced to the given object ID.
149 150 151 152 153 154 |
# File 'lib/perobs/Hash.rb', line 149 def _delete_reference_to_id(id) @data.delete_if do |k, v| v && v.respond_to?(:is_poxreference?) && v.id == id end @store.cache.cache_write(self) end |
#_deserialize(data) ⇒ Object
Restore the persistent data from a single data structure. This is a library internal method. Do not use outside of this library.
160 161 162 163 164 165 |
# File 'lib/perobs/Hash.rb', line 160 def _deserialize(data) @data = {} data.each { |k, v| @data[k] = v.is_a?(POReference) ? POXReference.new(@store, v.id) : v } @data end |
#_referenced_object_ids ⇒ Array of Integer
Return a list of all object IDs of all persistend objects that this Hash is referencing.
141 142 143 144 |
# File 'lib/perobs/Hash.rb', line 141 def _referenced_object_ids @data.each_value.select { |v| v && v.respond_to?(:is_poxreference?) }. map { |o| o.id } end |
#default=(value) ⇒ Object
Proxy for default= method.
133 134 135 136 |
# File 'lib/perobs/Hash.rb', line 133 def default=(value) _check_assignment_value(value) @data.default=(value) end |
#inspect ⇒ String
Textual dump for debugging purposes
169 170 171 172 173 174 175 176 |
# File 'lib/perobs/Hash.rb', line 169 def inspect "<#{self.class}:#{@_id}>\n{\n" + @data.map do |k, v| " #{k.inspect} => " + (v.respond_to?(:is_poxreference?) ? "<PEROBS::ObjectBase:#{v._id}>" : v.inspect) end.join(",\n") + "\n}\n" end |