Packages

  • package root

    Documentation/API for the Molecule library - a meta DSL for the Datomic database.

    Manual | scalamolecule.org | Github | Forum

    Definition Classes
    root
  • package molecule

    Molecule library - a Scala meta-DSL for the Datomic database.

    Molecule library - a Scala meta-DSL for the Datomic database.

    See api package for various api imports to start using Molecule.

    Sub-packages

    api Molecule API.
    ast Internal Molecule ASTs.
    boilerplate Internal interfaces for auto-generated DSL boilerplate code.
    composition    Builder methods to compose molecules.
    exceptions Exceptions thrown by Molecule.
    expression Attribute expressions and operations.
    facade Molecule facades to Datomic.
    factory Implicit macro methods `m` to instantiate molecules from custom DSL molecule constructs.
    input Input molecules awaiting input.
    macros Internal macros generating molecule code from custom DSL molecule constructs.
    generic Interfaces to generic information about datoms and Datomic database.
    ops Internal operational helpers for transforming DSL to molecule.
    schema Schema definition DSL.
    transform Internal transformers from DSL to Model/Query/Transaction.
    util Internal Java database functions for Datomic.

    Definition Classes
    root
  • package api

    Public interface to be imported to use Molecule.

    Public interface to be imported to use Molecule.

    To make the Molecule macro materializations as fast as possible we try to import as few macro implicits as possible. If your application code build molecules with at the most 10 attributes, then you can do the following import to start using Molecule:

    import molecule.api.out10._

    out means "output molecule" , and 10 the maximum arity or number of attributes of your molecules.

    If you use input molecules awaiting an input then you can add inX where X is how many inputs (1, 2 or 3) you will use, for instance:

    import molecule.api.in2_out10._

    This way we keep the implicit macro def lookups to a minimum and compilation speed as fast as possible.

    Arities can be changed anytime you like. But not to a lower arity than that of the molecules you use in scope of the import.

    Definition Classes
    molecule
  • package exception
    Definition Classes
    api
  • package get

    Synchronous getter methods to retrieve data from Datomic.

    Synchronous getter methods to retrieve data from Datomic.

    The Datomic On-Prem(ises) server model provides a Peer that returns data synchronously. The Peer which lives in application memory caches data aggressively and for data fitting in memory latency can be extremely low and queries return very fast. And even when access to disk is needed, clever branching is used. Memcached is also an option.

    The Datomic Cloud model data returns data asynchronously. If Datomic creates a Java API for the Cloud model, Molecule could relatively easy adapt to this model too. In the meanwhile, Future-wrapped methods in this package can be used.

    Molecule has 5 groups of synchronous getters, each returning data in various formats:

    • GetArray - fastest retrieved typed data set. Can be traversed with a fast while loop
    • GetIterable - for lazily traversing row by row
    • GetJson - data formatted as Json string
    • GetList - default getter returning Lists of tuples. Convenient typed data, suitable for smaller data sets
    • GetRaw - fastest retrieved raw un-typed data from Datomic

    Getters in each of the 5 groups come with 5 time-dependent variations:

    • get [current data]
    • getAsOf
    • getSince
    • getWith
    • getHistory

    Each time variation has various overloads taking different parameters (see each group for more info).

    Definition Classes
    api
    See also

    equivalent asynchronous getters in the getAsync package.

  • package getAsync

    Asynchronous getter methods to retrieve data from Datomic.

    Asynchronous getter methods to retrieve data from Datomic.

    For convenience, all synchronous getter methods from the get package are here wrapped in Futures.

    The Datomic On-Prem(ises) server model provides a Peer that returns data synchronously. The Peer which lives in application memory caches data aggressively and for data fitting in memory latency can be extremely low and queries return very fast. And even when access to disk is needed, clever branching is used. Memcached is also an option.

    The Datomic Cloud model data returns data asynchronously. If Datomic creates a Java API for the Cloud model, Molecule could relatively easy adapt to this model too. In the meanwhile, Future-wrapped methods in this package can be used.

    Molecule has 5 groups of asynchronous getters, each returning Futures of data in various formats:

    • GetAsyncArray - fastest retrieved typed data set. Can be traversed with a fast while loop
    • GetAsyncIterable - for lazily traversing row by row
    • GetAsyncJson - data formatted as Json string
    • GetAsyncList - default getter returning Lists of tuples. Convenient typed data, suitable for smaller data sets
    • GetAsyncRaw - fastest retrieved raw un-typed data from Datomic

    Getters in each of the 5 groups come with 5 time-dependent variations:

    • getAsync [current data]
    • getAsyncAsOf
    • getAsyncSince
    • getAsyncWith
    • getAsyncHistory

    Each time variation has various overloads taking different parameters (see each group for more info).

    Definition Classes
    api
    See also

    equivalent synchronous getters in the get package.

  • Entity
  • EntityOps
  • Molecule
  • OptionalMapOps
  • ShowDebug
  • TxMethods
  • core
  • in1_out1
  • in1_out10
  • in1_out11
  • in1_out12
  • in1_out13
  • in1_out14
  • in1_out15
  • in1_out16
  • in1_out17
  • in1_out18
  • in1_out19
  • in1_out2
  • in1_out20
  • in1_out21
  • in1_out22
  • in1_out3
  • in1_out4
  • in1_out5
  • in1_out6
  • in1_out7
  • in1_out8
  • in1_out9
  • in2_out1
  • in2_out10
  • in2_out11
  • in2_out12
  • in2_out13
  • in2_out14
  • in2_out15
  • in2_out16
  • in2_out17
  • in2_out18
  • in2_out19
  • in2_out2
  • in2_out20
  • in2_out21
  • in2_out22
  • in2_out3
  • in2_out4
  • in2_out5
  • in2_out6
  • in2_out7
  • in2_out8
  • in2_out9
  • in3_out1
  • in3_out10
  • in3_out11
  • in3_out12
  • in3_out13
  • in3_out14
  • in3_out15
  • in3_out16
  • in3_out17
  • in3_out18
  • in3_out19
  • in3_out2
  • in3_out20
  • in3_out21
  • in3_out22
  • in3_out3
  • in3_out4
  • in3_out5
  • in3_out6
  • in3_out7
  • in3_out8
  • in3_out9
  • out1
  • out10
  • out11
  • out12
  • out13
  • out14
  • out15
  • out16
  • out17
  • out18
  • out19
  • out2
  • out20
  • out21
  • out22
  • out3
  • out4
  • out5
  • out6
  • out7
  • out8
  • out9

trait TxMethods extends AnyRef

Transactional methods for bundled transactions and tx functions

Source
TxMethods.scala
Linear Supertypes
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  6. macro def debugTransact(txFnCall: Seq[Seq[Statement]], txMolecules: MoleculeBase*): Unit

    Debug tx function invocation

    Print transaction statements to output of a tx function invocation without affecting the live database.

    Debug tx function invocation

    Print transaction statements to output of a tx function invocation without affecting the live database.

    // Print debug info for tx function invocation
    debugTransact(transfer(fromAccount, toAccount, 20))
    
    // Prints produced tx statements to output:
    /*
    ## 1 ## TxReport
    ========================================================================
    1          ArrayBuffer(
      1          List(
        1          :db/add       17592186045445       :Account/balance    80        Card(1))
      2          List(
        1          :db/add       17592186045447       :Account/balance    720       Card(1)))
    ------------------------------------------------
    2          List(
      1    1     added: true ,   t: 13194139534345,   e: 13194139534345,   a: 50,   v: Thu Nov 22 16:23:09 CET 2018
    
      2    2     added: true ,   t: 13194139534345,   e: 17592186045445,   a: 64,   v: 80
           3     added: false,  -t: 13194139534345,  -e: 17592186045445,  -a: 64,  -v: 100
    
      3    4     added: true ,   t: 13194139534345,   e: 17592186045447,   a: 64,   v: 720
           5     added: false,  -t: 13194139534345,  -e: 17592186045447,  -a: 64,  -v: 700)
    ========================================================================
    */
    txFnCall

    Tx function invocation

    txMolecules

    Optional tx meta data molecules

  7. def debugTransact(stmtss: Seq[Seq[Statement]]*)(implicit conn: Conn): Unit

    Debug bundled transaction statements

    Add transaction statements from one or more molecule actions to debugTransact to see the bundled transaction statements.

    Debug bundled transaction statements

    Add transaction statements from one or more molecule actions to debugTransact to see the bundled transaction statements.

    debugTransact(
      // retract
      e1.getRetractTx,
      // save
      Ns.int(4).getSaveTx,
      // insert
      Ns.int.getInsertTx(List(5, 6)),
      // update
      Ns(e2).int(20).getUpdateTx
    )
    
    // Prints transaction data to output:
    /*
      ## 1 ## TxReport
      ========================================================================
      1          ArrayBuffer(
        1          List(
          1          :db.fn/retractEntity   17592186045445)
        2          List(
          1          :db/add       #db/id[:db.part/user -1000247]     :Ns/int          4           Card(1))
        3          List(
          1          :db/add       #db/id[:db.part/user -1000252]     :Ns/int          5           Card(1))
        4          List(
          1          :db/add       #db/id[:db.part/user -1000253]     :Ns/int          6           Card(1))
        5          List(
          1          :db/add       17592186045446                     :Ns/int          20          Card(1)))
      ------------------------------------------------
      2          List(
        1    1     added: true ,   t: 13194139534345,   e: 13194139534345,   a: 50,   v: Wed Nov 14 23:38:15 CET 2018
    
        2    2     added: false,  -t: 13194139534345,  -e: 17592186045445,  -a: 64,  -v: 1
    
        3    3     added: true ,   t: 13194139534345,   e: 17592186045450,   a: 64,   v: 4
    
        4    4     added: true ,   t: 13194139534345,   e: 17592186045451,   a: 64,   v: 5
    
        5    5     added: true ,   t: 13194139534345,   e: 17592186045452,   a: 64,   v: 6
    
        6    6     added: true ,   t: 13194139534345,   e: 17592186045446,   a: 64,   v: 20
             7     added: false,  -t: 13194139534345,  -e: 17592186045446,  -a: 64,  -v: 2)
      ========================================================================
    */
    stmtss

    Statement's from multiple molecule operations

    conn

    Implicit Conn value in scope

  8. final def eq(arg0: AnyRef): Boolean
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  17. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
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  18. def toString(): String
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  19. macro def transact(txFnCall: Seq[Seq[Statement]], txMolecules: MoleculeBase*): TxReport

    Transact tx function invocation

    Macro that takes a tx function invocation itself as its argument.

    Transact tx function invocation

    Macro that takes a tx function invocation itself as its argument. The tx function is analyzed by the macro and the necessary transaction preparations done at compile time.

    At runtime, the returned statements from the tx function is transacted as one atomic transaction.

    val txReport = transact(transfer(fromAccount, toAccount, 20))

    Transaction meta data molecules can be added

    // Add tx meta data that John did the transfer and that it is a scheduled transfer
    transact(
      transfer(fromAccount, toAccount, 20),
      Person.name("John"),
      UseCase.name("Scheduled transfer"))
    
    // Query multiple Tx meta data molecules
    Account(fromAccount).balance
      .Tx(Person.name_("John"))
      .Tx(UseCase.name_("Scheduled transfer")).get.head === 80
    Account(toAccount).balance
      .Tx(Person.name_("John"))
      .Tx(UseCase.name_("Scheduled transfer")).get.head === 720
    txFnCall

    Tx function invocation

    txMolecules

    Optional tx meta data molecules

    returns

    TxReport with result of transaction

  20. def transact(stmtss: Seq[Seq[Statement]]*)(implicit conn: Conn): TxReport

    Transact bundled transaction statements

    Supply transaction statements of one or more molecule actions to perform a single atomic transaction.

    Transact bundled transaction statements

    Supply transaction statements of one or more molecule actions to perform a single atomic transaction.

    transact(
      // retract entity
      e1.getRetractTx,
      // save new entity
      Ns.int(4).getSaveTx,
      // insert multiple new entities
      Ns.int.getInsertTx(List(5, 6)),
      // update entity
      Ns(e2).int(20).getUpdateTx
    )
    stmtss

    Statement's from multiple molecule operations

    conn

    Implicit Conn value in scope

    returns

    TxReport with result of transaction

  21. macro def transactAsync(txFnCall: Seq[Seq[Statement]], txMolecules: MoleculeBase*): TxReport

    Asynchronously transact tx function invocation

    Macro that takes a tx function invocation itself as its argument.

    Asynchronously transact tx function invocation

    Macro that takes a tx function invocation itself as its argument. The tx function is analyzed by the macro and the necessary transaction preparations done at compile time.

    At runtime, the returned statements from the tx function is asynchronously transacted as one atomic transaction using Datomic's asynchronous API.

    Await.result(
      transactAsync(transfer(fromAccount, toAccount, 20)) map { txReport =>
        Account(fromAccount).balance.get.head === 80 // (could be asynchronous too)
        Account(toAccount).balance.get.head === 720
      },
      2.seconds
    )

    Additional transaction meta data can be added

    Await.result(
      transactAsync(
        transfer(fromAccount, toAccount, 20),
        Person.name("John"),
        UseCase.name("Scheduled transfer")) map { txReport =>
          Account(fromAccount).balance
          .Tx(Person.name_("John"))
          .Tx(UseCase.name_("Scheduled transfer"))
          .get.head === 80 // (could be asynchronous too)
      },
      2.seconds
    )
    txFnCall

    Tx function invocation

    txMolecules

    Optional tx meta data molecules

    returns

    Future with TxReport with result of transaction

  22. def transactAsync(stmtss: Seq[Seq[Statement]]*)(implicit conn: Conn, ec: ExecutionContext): Future[TxReport]

    Asynchronously transact bundled transaction statements

    Asynchronously transact bundled transaction statements

    Supply transaction statements of one or more molecule actions to asynchronously transact a single atomic transaction.

    Await.result(
      transactAsync(
        e1.getRetractTx,
        Ns.int(4).getSaveTx,
        Ns.int.getInsertTx(List(5, 6)),
        Ns(e2).int(20).getUpdateTx
      ) map { bundleTx =>
        Ns.int.getAsync map { queryResult =>
          queryResult === List(3, 4, 5, 6, 20)
        }
      },
      2.seconds
    )
    stmtss

    Statement's from multiple molecule operations

    conn

    Implicit Conn value in scope

    returns

    Future with TxReport with result of transaction

  23. final def wait(): Unit
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    @throws( ... )
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Inherited from AnyRef

Inherited from Any

Bundled transactions

Multiple molecule operations in one atomic transaction.

Transaction functions

Atomic transaction logic with access to tx database value.

Ungrouped