{"action":"closed","issue":{"url":"https://api.github.com/repos/jankotek/mapdb/issues/549","labels_url":"https://api.github.com/repos/jankotek/mapdb/issues/549/labels{/name}","comments_url":"https://api.github.com/repos/jankotek/mapdb/issues/549/comments","events_url":"https://api.github.com/repos/jankotek/mapdb/issues/549/events","html_url":"https://github.com/jankotek/mapdb/issues/549","id":95379883,"number":549,"title":"Could DB make or get ?","user":{"login":"bwzhang2011","id":749788,"avatar_url":"https://avatars.githubusercontent.com/u/749788?v=3","gravatar_id":"","url":"https://api.github.com/users/bwzhang2011","html_url":"https://github.com/bwzhang2011","followers_url":"https://api.github.com/users/bwzhang2011/followers","following_url":"https://api.github.com/users/bwzhang2011/following{/other_user}","gists_url":"https://api.github.com/users/bwzhang2011/gists{/gist_id}","starred_url":"https://api.github.com/users/bwzhang2011/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bwzhang2011/subscriptions","organizations_url":"https://api.github.com/users/bwzhang2011/orgs","repos_url":"https://api.github.com/users/bwzhang2011/repos","events_url":"https://api.github.com/users/bwzhang2011/events{/privacy}","received_events_url":"https://api.github.com/users/bwzhang2011/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/jankotek/mapdb/labels/2.0","name":"2.0","color":"009800"},{"url":"https://api.github.com/repos/jankotek/mapdb/labels/document","name":"document","color":"0052cc"}],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":12,"created_at":"2015-07-16T08:31:47Z","updated_at":"2015-08-18T07:44:36Z","closed_at":"2015-08-18T07:44:36Z","body":"@jankotek, as we use dbMaker to create db associated with either memory one or file based one.\r\nas for the file one, the current use cases need us to create the mapdb (just mean the DB instance) many times. just like the application will generate daily file and I will create the mapdb instance based on the daily file. so here comes my doubt, if I could not set the db instance to be the global one, I should get the DB (or open such exists) due to whether the file exists or not. so I dare Maker class should leave us such to open the exists file for DB creation. what's more, I notice that HTreeMapMaker  to  create the HTreeMap with makeOrGet(). so how could I generate the HTreeMap based on different file. here comes some use cases:\r\n```\r\npublic class AbstractMonitorCompositeStoreImpl extends MapStoreAdapter<String, MonitorComposite>\r\n\t\timplements IMonitorCompositeStore {\r\n\t@Override\r\n\tpublic void store(final String key, final MonitorComposite value) {\r\n\r\n\t}\r\n\r\n\t@Override\r\n\tpublic MonitorComposite load(final String key) {\r\n\t\treturn null;\r\n\t}\r\n\r\n\t@Override\r\n\tpublic Set<String> loadAllKeys() {\r\n\t\treturn null;\r\n\t}\r\n\r\n}\r\n```\r\njust like the mapstore (from hazelcast) I want to persist the object MonitorComposite  into mapdb with special key. and I want to generate many files based the key with some configuration just like\r\nparentpath/date/db.data    the date change daily and each time when it invoke store I will load the DB according to the key (just for HTreeMap creation) and then store value afterwards."}}