net.liftweb.http

Bindings

object Bindings extends AnyRef

A collection of types and implicit transformations used to allow composition of page elements based upon the types of rendered objects.

In Lift, a "snippet" is a function from NodeSeq => NodeSeq, where the argument to the function is a template, and the result is a fragment of a page to be rendered. Of course, this is a bit of an abbreviation; the snippet function also has an argument which is the application state made available from S. A DataBinding[T] is very similar in this respect; it is a function from some piece of information of type T to a function from NodeSeq => NodeSeq. Since DataBinding is strongly typed with respect to the type of information being rendered, DataBinding instances are ideal for the rendering of objects that is used to build up snippets. For example:

import net.liftweb.http.Bindings._

case class MyClass(str: String, i: Int, other: MyOtherClass) case class MyOtherClass(foo: String)

trait MyClassBinding extends DataBinding[MyClass] { implicit val otherBinding: DataBinding[MyOtherClass]

override def apply(entity: MyClass) = (xhtml: NodeSeq) => { val otherTemplate = chooseTemplate("myclass", "other", xhtml) bind( "myclass", xhtml, "str" -> Text("#" + entity.str + "#"), "i" -> Text(entity.i.toString), "other" -> entity.other.bind(otherTemplate) ) }

}

object myOtherClassBinding extends DataBinding[MyOtherClass] { override def apply(other: MyOtherClass) = (xhtml: NodeSeq) => { bind("other", xhtml, "foo" -> Text("%" + other.foo + "%")) } }

object MyClassConcreteBinding extends MyClassBinding { override val otherBinding = myOtherClassBinding }

In this example, two classes and their associated bindings are constructed; the first binding for MyClass is abstract, needing a specific instance of DataBinding[MyOtherClass] to enable the implicit conversion needed to render the contained MyOtherClass instance. A subtemplate is selected, and the call to other.bind both necessitates the implicit conversion to a Bindings.Binder instance and applies the appropriate formatting. You can see how this usage keeps the concerns of the view and the model nicely separated, while allowing composition over object graphs.

Please see the tests, as well as this blog post for additional details.

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Type Members

  1. case class Binder (binding: Binding) extends Product

    A decorator for a binding function that allows it to be called as bind() rather than apply().

  2. type Binding = (NodeSeq) ⇒ NodeSeq

  3. type DataBinding [T] = (T) ⇒ (NodeSeq) ⇒ NodeSeq

Value Members

  1. def != (arg0: AnyRef) : Boolean

    attributes: final
    definition classes: AnyRef
  2. def != (arg0: Any) : Boolean

    o != arg0 is the same as !(o == (arg0)).

    o != arg0 is the same as !(o == (arg0)).

    arg0

    the object to compare against this object for dis-equality.

    returns

    false if the receiver object is equivalent to the argument; true otherwise.

    attributes: final
    definition classes: Any
  3. def ## () : Int

    attributes: final
    definition classes: AnyRef → Any
  4. def $asInstanceOf [T0] () : T0

    attributes: final
    definition classes: AnyRef
  5. def $isInstanceOf [T0] () : Boolean

    attributes: final
    definition classes: AnyRef
  6. def == (arg0: AnyRef) : Boolean

    o == arg0 is the same as if (o eq null) arg0 eq null else o.equals(arg0).

    o == arg0 is the same as if (o eq null) arg0 eq null else o.equals(arg0).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    attributes: final
    definition classes: AnyRef
  7. def == (arg0: Any) : Boolean

    o == arg0 is the same as o.equals(arg0).

    o == arg0 is the same as o.equals(arg0).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    attributes: final
    definition classes: Any
  8. object EmptyBinding extends (NodeSeq) ⇒ NodeSeq

    Bind any input value to the empty NodeSeq.

  9. def asInstanceOf [T0] : T0

    This method is used to cast the receiver object to be of type T0.

    This method is used to cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expressionList(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

    returns

    the receiver object.

    attributes: final
    definition classes: Any
  10. implicit def binder (binding: Binding) : Binder

    Wrap the specified Binding (a function from NodeSeq => NodeSeq) in a Binder so that it can be applied using Binder's bind methods.

    Wrap the specified Binding (a function from NodeSeq => NodeSeq) in a Binder so that it can be applied using Binder's bind methods.

    attributes: implicit
  11. implicit def binder [T] (t: T)(implicit binding: DataBinding[T]) : Binder

    Implicitly convert the specified object to a binder for that object if a DataBinding for that object's type is available in implicit scope.

    Implicitly convert the specified object to a binder for that object if a DataBinding for that object's type is available in implicit scope. This essentially adds a bind() method to an object if an appropriate implicit DataBinding is available.

    attributes: implicit
  12. def clone () : AnyRef

    This method creates and returns a copy of the receiver object.

    This method creates and returns a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    attributes: protected
    definition classes: AnyRef
  13. def eq (arg0: AnyRef) : Boolean

    This method is used to test whether the argument (arg0) is a reference to the receiver object (this).

    This method is used to test whether the argument (arg0) is a reference to the receiver object (this).

    The eq method implements an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation] on non-null instances of AnyRef: * It is reflexive: for any non-null instance x of type AnyRef, x.eq(x) returns true. * It is symmetric: for any non-null instances x and y of type AnyRef, x.eq(y) returns true if and only if y.eq(x) returns true. * It is transitive: for any non-null instances x, y, and z of type AnyRef if x.eq(y) returns true and y.eq(z) returns true, then x.eq(z) returns true.

    Additionally, the eq method has three other properties. * It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false. * For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false. * null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    arg0

    the object to compare against this object for reference equality.

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    attributes: final
    definition classes: AnyRef
  14. def equals (arg0: Any) : Boolean

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence.

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence.

    The default implementations of this method is an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation]: * It is reflexive: for any instance x of type Any, x.equals(x) should return true. * It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true. * It is transitive: for any instances x, y, and z of type AnyRef if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

    If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is often necessary to override hashCode to ensure that objects that are "equal" (o1.equals(o2) returns true) hash to the same scala.Int (o1.hashCode.equals(o2.hashCode)).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    definition classes: AnyRef → Any
  15. def finalize () : Unit

    This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

    This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

    The details of when and if the finalize method are invoked, as well as the interaction between finalizeand non-local returns and exceptions, are all platform dependent.

    attributes: protected
    definition classes: AnyRef
  16. def getClass () : java.lang.Class[_]

    Returns a representation that corresponds to the dynamic class of the receiver object.

    Returns a representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    attributes: final
    definition classes: AnyRef
  17. def hashCode () : Int

    Returns a hash code value for the object.

    Returns a hash code value for the object.

    The default hashing algorithm is platform dependent.

    Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

    returns

    the hash code value for the object.

    definition classes: AnyRef → Any
  18. def isInstanceOf [T0] : Boolean

    This method is used to test whether the dynamic type of the receiver object is T0.

    This method is used to test whether the dynamic type of the receiver object is T0.

    Note that the test result of the test is modulo Scala's erasure semantics. Therefore the expression1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    attributes: final
    definition classes: Any
  19. def ne (arg0: AnyRef) : Boolean

    o.ne(arg0) is the same as !(o.eq(arg0)).

    o.ne(arg0) is the same as !(o.eq(arg0)).

    arg0

    the object to compare against this object for reference dis-equality.

    returns

    false if the argument is not a reference to the receiver object; true otherwise.

    attributes: final
    definition classes: AnyRef
  20. def notify () : Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    attributes: final
    definition classes: AnyRef
  21. def notifyAll () : Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    attributes: final
    definition classes: AnyRef
  22. def synchronized [T0] (arg0: T0) : T0

    attributes: final
    definition classes: AnyRef
  23. def toString () : String

    Returns a string representation of the object.

    Returns a string representation of the object.

    The default representation is platform dependent.

    returns

    a string representation of the object.

    definition classes: AnyRef → Any
  24. def wait () : Unit

    attributes: final
    definition classes: AnyRef
  25. def wait (arg0: Long, arg1: Int) : Unit

    attributes: final
    definition classes: AnyRef
  26. def wait (arg0: Long) : Unit

    attributes: final
    definition classes: AnyRef

Inherited from AnyRef

Inherited from Any