Package io.objectbox

Class BoxStoreBuilder

    • Field Detail

      • DEFAULT_MAX_DB_SIZE_KBYTE

        public static final int DEFAULT_MAX_DB_SIZE_KBYTE
        The default maximum size the DB can grow to, which can be overwritten using maxSizeInKByte.
        See Also:
        Constant Field Values
    • Constructor Detail

      • BoxStoreBuilder

        @Internal
        public BoxStoreBuilder​(byte[] model)
        Called internally from the generated class "MyObjectBox". Check MyObjectBox.builder() to get an instance.
    • Method Detail

      • createDebugWithoutModel

        @Internal
        public static BoxStoreBuilder createDebugWithoutModel()
        Not for application use, for DebugCursor.
      • baseDirectory

        public BoxStoreBuilder baseDirectory​(java.io.File baseDirectory)
        In combination with name(String), this lets you specify the location of where the DB files should be stored. Cannot be used in combination with directory(File).
      • androidContext

        public BoxStoreBuilder androidContext​(java.lang.Object context)
        On Android, you can pass a Context to set the base directory using this method. This will conveniently configure the storage location to be in the files directory of your app.

        In more detail, this assigns the base directory (see baseDirectory) to context.getFilesDir() + "/objectbox/". Thus, when using the default name (also "objectbox" unless overwritten using name(String)), the default location of DB files will be "objectbox/objectbox/" inside the app files directory. If you specify a custom name, for example with name("foobar"), it would become "objectbox/foobar/".

        Alternatively, you can also use baseDirectory or directory(File) instead.

      • androidReLinker

        public BoxStoreBuilder androidReLinker​(java.lang.Object reLinkerInstance)
        Pass a custom ReLinkerInstance, for example ReLinker.log(logger) to use for loading the native library on Android devices. Note that setting androidContext(Object) is required for ReLinker to work.
      • fileMode

        public BoxStoreBuilder fileMode​(int mode)
        Specify unix-style file permissions for database files. E.g. for -rw-r---- (owner, group, other) pass the octal code 0640. Any newly generated directory additionally gets searchable (01) for groups with read or write permissions. It's not allowed to pass in an executable flag.
      • maxReaders

        public BoxStoreBuilder maxReaders​(int maxReaders)
        Sets the maximum number of concurrent readers. For most applications, the default is fine (~ 126 readers).

        A "reader" is short for a thread involved in a read transaction.

        If you hit DbMaxReadersExceededException, you should first worry about the amount of threads you are using. For highly concurrent setups (e.g. you are using ObjectBox on the server side) it may make sense to increase the number. Note: Each thread that performed a read transaction and is still alive holds on to a reader slot. These slots only get vacated when the thread ends. Thus, be mindful with the number of active threads. Alternatively, you can opt to try the experimental noReaderThreadLocals option flag.

      • noReaderThreadLocals

        public BoxStoreBuilder noReaderThreadLocals()
        Disables the usage of thread locals for "readers" related to read transactions. This can make sense if you are using a lot of threads that are kept alive. Note: This is still experimental, as it comes with subtle behavior changes at a low level and may affect corner cases with e.g. transactions, which may not be fully tested at the moment.
      • maxSizeInKByte

        public BoxStoreBuilder maxSizeInKByte​(long maxSizeInKByte)
        Sets the maximum size the database file can grow to. By default this is 1 GB, which should be sufficient for most applications.

        In general, a maximum size prevents the DB from growing indefinitely when something goes wrong (for example you insert data in an infinite loop).

      • readOnly

        public BoxStoreBuilder readOnly()
        Open the store in read-only mode: no schema update, no write transactions are allowed (would throw).
      • usePreviousCommit

        public BoxStoreBuilder usePreviousCommit()
        Ignores the latest data snapshot (committed transaction state) and uses the previous snapshot instead. When used with care (e.g. backup the DB files first), this option may also recover data removed by the latest transaction.

        To ensure no data is lost accidentally, it is recommended to use this in combination with readOnly() to examine and validate the database first.

      • validateOnOpen

        public BoxStoreBuilder validateOnOpen​(short validateOnOpenMode)
        When a database is opened, ObjectBox can perform additional consistency checks on its database structure. Reliable file systems already guarantee consistency, so this is primarily meant to deal with unreliable OSes, file systems, or hardware.

        Note: ObjectBox builds upon ACID storage, which already has strong consistency mechanisms in place.

        Parameters:
        validateOnOpenMode - One of ValidateOnOpenMode.
      • validateOnOpenPageLimit

        public BoxStoreBuilder validateOnOpenPageLimit​(long limit)
        To fine-tune validateOnOpen(short), you can specify a limit on how much data is looked at. This is measured in "pages" with a page typically holding 4000. Usually a low number (e.g. 1-20) is sufficient and does not impact startup performance significantly.

        This can only be used with ValidateOnOpenMode.Regular and ValidateOnOpenMode.WithLeaves.

      • debugRelations

        public BoxStoreBuilder debugRelations()
        Enables some debug logging for relations.
      • queryAttempts

        @Experimental
        public BoxStoreBuilder queryAttempts​(int queryAttempts)
        For massive concurrent setups (app is using a lot of threads), you can enable automatic retries for queries. This can resolve situations in which resources are getting sparse (e.g. DbMaxReadersExceededException or other variations of DbException are thrown during query execution).
        Parameters:
        queryAttempts - number of attempts a query find operation will be executed before failing. Recommended values are in the range of 2 to 5, e.g. a value of 3 as a starting point.
      • initialDbFile

        @Experimental
        public BoxStoreBuilder initialDbFile​(java.io.File initialDbFile)
        Let's you specify an DB file to be used during initial start of the app (no DB file exists yet).
      • initialDbFile

        @Experimental
        public BoxStoreBuilder initialDbFile​(Factory<java.io.InputStream> initialDbFileFactory)
        Let's you specify a provider for a DB file to be used during initial start of the app (no DB file exists yet). The provider will only be called if no DB file exists yet.
      • build

        public BoxStore build()
        Builds a BoxStore using any given configuration.