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Editing: cdesc-PStore.yaml
--- !ruby/object:RI::ClassDescription attributes: [] class_methods: - !ruby/object:RI::MethodSummary name: new comment: - !ruby/struct:SM::Flow::P body: PStore implements a file based persistence mechanism based on a Hash. User code can store hierarchies of Ruby objects (values) into the data store file by name (keys). An object hierarchy may be just a single object. User code may later read values back from the data store or even update data, as needed. - !ruby/struct:SM::Flow::P body: The transactional behavior ensures that any changes succeed or fail together. This can be used to ensure that the data store is not left in a transitory state, where some values were updated but others were not. - !ruby/struct:SM::Flow::P body: Behind the scenes, Ruby objects are stored to the data store file with Marshal. That carries the usual limitations. Proc objects cannot be marshalled, for example. - !ruby/struct:SM::Flow::H level: 2 text: "Usage example:" - !ruby/struct:SM::Flow::VERB body: " require "pstore"\n\n # a mock wiki object...\n class WikiPage\n def initialize( page_name, author, contents )\n @page_name = page_name\n @revisions = Array.new\n\n add_revision(author, contents)\n end\n\n attr_reader :page_name\n\n def add_revision( author, contents )\n @revisions << { :created => Time.now,\n :author => author,\n :contents => contents }\n end\n\n def wiki_page_references\n [@page_name] + @revisions.last[:contents].scan(/\\b(?:[A-Z]+[a-z]+){2,}/)\n end\n\n # ...\n end\n\n # create a new page...\n home_page = WikiPage.new( "HomePage", "James Edward Gray II",\n "A page about the JoysOfDocumentation..." )\n\n # then we want to update page data and the index together, or not at all...\n wiki = PStore.new("wiki_pages.pstore")\n wiki.transaction do # begin transaction; do all of this or none of it\n # store page...\n wiki[home_page.page_name] = home_page\n # ensure that an index has been created...\n wiki[:wiki_index] ||= Array.new\n # update wiki index...\n wiki[:wiki_index].push(*home_page.wiki_page_references)\n end # commit changes to wiki data store file\n\n ### Some time later... ###\n\n # read wiki data...\n wiki.transaction(true) do # begin read-only transaction, no changes allowed\n wiki.roots.each do |data_root_name|\n p data_root_name\n p wiki[data_root_name]\n end\n end\n" constants: - !ruby/object:RI::Constant comment: name: RDWR_ACCESS value: File::RDWR | File::CREAT | binmode - !ruby/object:RI::Constant comment: name: RD_ACCESS value: File::RDONLY | binmode - !ruby/object:RI::Constant comment: name: WR_ACCESS value: File::WRONLY | File::CREAT | File::TRUNC | binmode full_name: PStore includes: [] instance_methods: - !ruby/object:RI::MethodSummary name: "[]" - !ruby/object:RI::MethodSummary name: "[]=" - !ruby/object:RI::MethodSummary name: abort - !ruby/object:RI::MethodSummary name: commit - !ruby/object:RI::MethodSummary name: commit_new - !ruby/object:RI::MethodSummary name: delete - !ruby/object:RI::MethodSummary name: fetch - !ruby/object:RI::MethodSummary name: in_transaction - !ruby/object:RI::MethodSummary name: in_transaction_wr - !ruby/object:RI::MethodSummary name: path - !ruby/object:RI::MethodSummary name: root? - !ruby/object:RI::MethodSummary name: roots - !ruby/object:RI::MethodSummary name: transaction name: PStore superclass: Object
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