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  • 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
    Definition Classes
    molecule
  • 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.

  • GetAsyncArray
  • GetAsyncIterable
  • GetAsyncJson
  • GetAsyncList
  • GetAsyncRaw
t

molecule.api.getAsync

GetAsyncIterable

trait GetAsyncIterable[Tpl] extends AnyRef

Asynchronous data getter methods on molecules returning Future[Iterable[Tpl]].

Suitable for data sets that are lazily consumed.

val iterableFuture: Future[Iterable[(String, Int)]] = Person.name.age.getAsyncIterable
for {
  iterable <- iterableFuture
} yield {
  iterable.iterator.next === ("Ben" 42)
}

Each asynchronous getter in this package simply wraps the result of its equivalent synchronous getter (in the get package) in a Future. getAsyncIterableAsOf thus wraps the result of getIterableAsOf in a Future and so on.

Self Type
Molecule[Tpl] with GetIterable[Tpl]
Source
GetAsyncIterable.scala
Linear Supertypes
AnyRef, Any
Known Subclasses
Molecule, Molecule01, Molecule02, Molecule03, Molecule04, Molecule05, Molecule06, Molecule07, Molecule08, Molecule09, Molecule10, Molecule11, Molecule12, Molecule13, Molecule14, Molecule15, Molecule16, Molecule17, Molecule18, Molecule19, Molecule20, Molecule21, Molecule22
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  9. def getAsyncIterable(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching the molecule.

    Get Future with Iterable of all rows as tuples matching the molecule.

    Rows are lazily type-casted on each call to iterator.next().

    For more info and code examples see equivalent synchronous getIterable method.

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is a tuple of types matching the attributes of the molecule

  10. def getAsyncIterableAsOf(date: Date)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule as of date.

    Get Future with Iterable of all rows as tuples matching molecule as of date.

    Get data at a human point in time (a java.util.Date).

    For more info and code examples see equivalent synchronous getIterableAsOf method.

    date

    java.util.Date

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is tuple of data matching molecule

    See also

    Manual on asof/since

  11. def getAsyncIterableAsOf(tx: TxReport)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule as of tx.

    Get Future with Iterable of all rows as tuples matching molecule as of tx.

    Datomic's internal asOf method can take a transaction entity id as argument to retrieve a database value as of that transaction (including).

    Instead of supplying the transaction entity id, in Molecule we supply a TxReport that contains the transaction entity id (which is used as argument to Datomic internally). This is more convenient when using Molecule since we get a TxReport from transaction operations like get, update, retract etc.

    For more info and code examples see equivalent synchronous getIterableAsOf method.

    tx

    TxReport (returned from all molecule transaction operations)

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is tuple of data matching molecule

    See also

    Manual on asof/since

  12. def getAsyncIterableAsOf(t: Long)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule as of transaction time t.

    Get Future with Iterable of all rows as tuples matching molecule as of transaction time t.

    Transaction time t is an auto-incremented transaction number assigned internally by Datomic.

    t can for instance be retrieved in a getHistory call for an attribute and then be used to get data as of that point in time (including that transaction).

    Call getIterableAsOf for large result sets to maximize runtime performance. Data is lazily type-casted on each call to next on the iterator.

    For more info and code examples see equivalent synchronous getIterableAsOf method.

    t

    Transaction time t

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is tuple of data matching molecule

    See also

    Manual on asof/since

  13. def getAsyncIterableSince(date: Date)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule since date.

    Get Future with Iterable of all rows as tuples matching molecule since date.

    Get data added/retracted since a human point in time (a java.util.Date).

    For more info and code examples see equivalent synchronous getIterableSince method.

    date

    java.util.Date

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is tuple of data matching molecule

    See also

    Manual on asof/since

  14. def getAsyncIterableSince(tx: TxReport)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule since tx.

    Get Future with Iterable of all rows as tuples matching molecule since tx.

    Datomic's internal since method can take a transaction entity id as argument to retrieve a database value since that transaction (excluding the transaction itself).

    Instead of supplying the transaction entity id, in Molecule we supply a TxReport that contains the transaction entity id (which is used as argument to Datomic internally). This is more convenient when using Molecule since we get a TxReport from transaction operations like get, update, retract etc.

    For more info and code examples see equivalent synchronous getIterableSince method.

    tx

    TxReport

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is tuple of data matching molecule

    See also

    Manual on asof/since

  15. def getAsyncIterableSince(t: Long)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule since transaction time t.

    Get Future with Iterable of all rows as tuples matching molecule since transaction time t.

    Transaction time t is an auto-incremented transaction number assigned internally by Datomic.

    Call getIterableSince for large result sets to maximize runtime performance. Data is lazily type-casted on each call to next on the iterator.

    For more info and code examples see equivalent synchronous getIterableSince method.

    t

    Transaction time t

    conn

    Implicit Conn value in scope

    returns

    Iterable[Tpl] where Tpl is tuple of data matching molecule

    See also

    Manual on asof/since

  16. def getAsyncIterableWith(txData: List[_])(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule with applied raw transaction data.

    Get Future with Iterable of all rows as tuples matching molecule with applied raw transaction data.

    Apply raw transaction data to in-memory "branch" of db without affecting db. *

    * For more info and code examples see equivalent synchronous * getIterableWith method.

    txData

    Raw transaction data as java.util.List[Object]

    conn

    Implicit Conn value in scope

    returns

    Iterable of molecule data

    See also

    Manual on with

  17. def getAsyncIterableWith(txMolecules: Seq[Seq[Statement]]*)(implicit conn: Conn): Future[Iterable[Tpl]]

    Get Future with Iterable of all rows as tuples matching molecule with applied molecule transaction data.

    Get Future with Iterable of all rows as tuples matching molecule with applied molecule transaction data.

    Apply one or more molecule transactions to in-memory "branch" of db without affecting db.

    For more info and code examples see equivalent synchronous getIterableWith method.

    Multiple transactions can be applied to test more complex what-if scenarios!

    txMolecules

    Transaction statements from applied Molecules with test data

    conn

    Implicit Conn value in scope

    returns

    Iterable of molecule data

    See also

    Manual on with

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Inherited from AnyRef

Inherited from Any

getAsync

getAsyncIterableAsOf

getAsyncIterableSince

getAsyncIterableWith

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