SequencedInStackHandler

Handler that forwards inputs to a first handler until that handler yields a result, at which point the result is used to create a second handler, to which all further inputs are forwarded until it yields a result.

Before the second handler is generated, the input "stack" is tracked so that it can be replayed to the second handler (so that it can acquire the correct context even though it was not available when the inputs forming that context were initially handled). The "stack" behavior is generalized with the Stackable typeclass.

An example usage of this is to faciliate creation of a Parser for an XML element which starts with some "dictionary" element, followed by a large number of "data" objects that reference the dictionary. Normally, a user of xml-spac would have to choose between;

loading the large list of data objects into a List (high memory usage) in order to use regular parser combination methods like and
creating an external map and having the dictionary parser side effect by populating the map, and the data object parser read from that map (this is against the spirit of xml-spac since it breaks the immutability/encapsulation of the parser). Instead, with this handler, the user can write a parser for the dictionary element and have its result be passed into the parser for its sibling elements (the data elements). No external mutable state is required.

In: The input type
T1: The first handler's result type
T2: The second handler's result type

Source: SequencedInStackHandler.scala

Linear Supertypes

Handler[In, T2], AnyRef, Any

Instance Constructors

new SequencedInStackHandler(handler1: Handler[In, T1], getHandler2: (T1) ⇒ Handler[In, T2])(implicit arg0: Stackable[In])

handler1
The first handler
getHandler2
A function to generate the second handler from the first handler's result

Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
def +(other: String): String

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to any2stringadd[SequencedInStackHandler[In, T1, T2]] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd
def ->[B](y: B): (SequencedInStackHandler[In, T1, T2], B)

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to ArrowAssoc[SequencedInStackHandler[In, T1, T2]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def ensuring(cond: (SequencedInStackHandler[In, T1, T2]) ⇒ Boolean, msg: ⇒ Any): SequencedInStackHandler[In, T1, T2]

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to Ensuring[SequencedInStackHandler[In, T1, T2]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: (SequencedInStackHandler[In, T1, T2]) ⇒ Boolean): SequencedInStackHandler[In, T1, T2]

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to Ensuring[SequencedInStackHandler[In, T1, T2]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean, msg: ⇒ Any): SequencedInStackHandler[In, T1, T2]

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to Ensuring[SequencedInStackHandler[In, T1, T2]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean): SequencedInStackHandler[In, T1, T2]

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to Ensuring[SequencedInStackHandler[In, T1, T2]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def formatted(fmtstr: String): String

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to StringFormat[SequencedInStackHandler[In, T1, T2]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def handleEnd(): T2

Causes this handler to finalize and produce a result.
Causes this handler to finalize and produce a result.
This method should not be called if isFinished is already true.
returns
The final output of this parser

Definition Classes
SequencedInStackHandler → Handler
def handleError(error: Throwable): Option[T2]

Causes this handler to process an error.
Causes this handler to process an error.
This method should not be called if isFinished == true
error
an error to be processed
returns
An option containing the final output if this handler became finished as a result of processing the error, or None if the handler is ready for more input.

Definition Classes
SequencedInStackHandler → Handler
def handleInput(event: In): Option[T2]

Causes this handler to process an input element.
Causes this handler to process an input element.
This method should not be called if isFinished == true
returns
An option containing the final output if this handler became finished as a result of processing the input, or None if the handler is ready for more input.

Definition Classes
SequencedInStackHandler → Handler
def hashCode(): Int

Definition Classes
AnyRef → Any
def isFinished: Boolean

Tells if this handler is finished.
Tells if this handler is finished.
If a handler is finished, its handleX methods should no longer be called. Doing so after the handler finishes will cause undefined behavior. Typically a handler should be discarded once it is finished.
returns
whether this handler is finished

Definition Classes
SequencedInStackHandler → Handler
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String

Definition Classes
SequencedInStackHandler → AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def →[B](y: B): (SequencedInStackHandler[In, T1, T2], B)

Implicit information
This member is added by an implicit conversion from SequencedInStackHandler[In, T1, T2] to ArrowAssoc[SequencedInStackHandler[In, T1, T2]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

Related Doc: package handlers

class SequencedInStackHandler[In, T1, T2] extends Handler[In, T2]

Instance Constructors

new SequencedInStackHandler(handler1: Handler[In, T1], getHandler2: (T1) ⇒ Handler[In, T2])(implicit arg0: Stackable[In])

Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

def +(other: String): String

def ->[B](y: B): (SequencedInStackHandler[In, T1, T2], B)

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

def ensuring(cond: (SequencedInStackHandler[In, T1, T2]) ⇒ Boolean, msg: ⇒ Any): SequencedInStackHandler[In, T1, T2]

def ensuring(cond: (SequencedInStackHandler[In, T1, T2]) ⇒ Boolean): SequencedInStackHandler[In, T1, T2]

def ensuring(cond: Boolean, msg: ⇒ Any): SequencedInStackHandler[In, T1, T2]

def ensuring(cond: Boolean): SequencedInStackHandler[In, T1, T2]

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

def formatted(fmtstr: String): String

final def getClass(): Class[_]

def handleEnd(): T2

def handleError(error: Throwable): Option[T2]

def handleInput(event: In): Option[T2]

def hashCode(): Int

def isFinished: Boolean

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

def →[B](y: B): (SequencedInStackHandler[In, T1, T2], B)

Inherited from Handler[In, T2]

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from SequencedInStackHandler[In, T1, T2] to any2stringadd[SequencedInStackHandler[In, T1, T2]]

Inherited by implicit conversion StringFormat from SequencedInStackHandler[In, T1, T2] to StringFormat[SequencedInStackHandler[In, T1, T2]]

Inherited by implicit conversion Ensuring from SequencedInStackHandler[In, T1, T2] to Ensuring[SequencedInStackHandler[In, T1, T2]]

Inherited by implicit conversion ArrowAssoc from SequencedInStackHandler[In, T1, T2] to ArrowAssoc[SequencedInStackHandler[In, T1, T2]]

Ungrouped