Module org.apache.jena.arq
Package org.apache.jena.sparql.engine.binding

Class BindingBuilder

java.lang.Object
org.apache.jena.sparql.engine.binding.BindingBuilder
public class BindingBuilder extends Object
Build Bindings.

Binding are immutable and can not be changed once constructed. A BindingBuilder accumulates some var/node pairs and, at the build step, chooses the most efficient Binding implementation. 

   Binding binding = Binding.builder()
                        .add(var, value)
                        ...
                        .build();
The build() method can only be called once per binding constructed. A BindingBuilder can be reused but is not thread safe.

Example: 

   BindingBuilder builder = Binding.builder(parent);
   for .... {

      builder.reset()
      for ( ... each variable ... ) {
          builder.add(var, node)
      }
      Binding binding = builder.build();
      ... accumulate binding ...
   }

Example: 

   BindingBuilder builder = Binding.builder(parent);
   for .... {
      Binding binding =
          builder.reset()
             .add(var1, node1)
             .add(var2, node2)
             .add(var3, node3)
             .build();
      }
      ... accumulate binding ...
   }
See also BindingFactory. When the number of var/node pairs is fixed and known, operations in BindingFactory directly create a binding without needing a builder.

  • Field Details

    • noParent

      public static final Binding noParent

  • Method Details

    • create

      public static BindingBuilder create()

    • create

      public static BindingBuilder create(Binding parent)

    • set

      public BindingBuilder set(Var var, org.apache.jena.graph.Node node)
      Accumulate (var,value) pairs. Allow binding in this level to be replaced (i.e. not in parent)

    • add

      public BindingBuilder add(Var var, org.apache.jena.graph.Node node)

    • addAll

      public BindingBuilder addAll(Binding other)
      Add all the (var, value) pairs from another binding

    • getOrSame

      public org.apache.jena.graph.Node getOrSame(Var var)
      Get or return the variable.

    • get

      public org.apache.jena.graph.Node get(Var var)

    • contains

      public boolean contains(Var var)

    • isEmpty

      public boolean isEmpty()

    • vars1

      public Iterator<Var> vars1()
      Variables in the builder - does not include the parent.

    • reset

      public BindingBuilder reset()
      Reset the builder state, while keeping the parent

    • build

      public Binding build()
      Construct the binding. This can be called only once for a binding but the builder can be reused after a call to reset().

    • snapshot

      public Binding snapshot()
      Build a view of the current state.

      Do not modify the builder while this binding is in use. Changes to the builder make this view unstable. To create a finished binding, call build().

    • toString

      public String toString()
      Overrides:
      toString in class Object