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

Class BindingBuilder

java.lang.Object

org.apache.jena.sparql.engine.binding.BindingBuilder

public class BindingBuilder
extends java.lang.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 Summary

Fields

Modifier and Type	Field	Description
static Binding	noParent

Method Summary

Modifier and Type	Method	Description
BindingBuilder	add(Var var, Node node)
BindingBuilder	addAll(Binding other)	Add all the (var, value) pairs from another binding
Binding	build()	Construct the binding.
boolean	contains(Var var)
static BindingBuilder	create()
static BindingBuilder	create(Binding parent)
Node	get(Var var)
Node	getOrSame(Var var)	Get or return the variable.
boolean	isEmpty()
BindingBuilder	reset()	Reset the builder state, while keeping the parent
BindingBuilder	set(Var var, Node node)	Accumulate (var,value) pairs.
Binding	snapshot()	Build a view of the current state.
java.lang.String	toString()
java.util.Iterator<Var>	vars1()	Variables in the builder - does not include the parent.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

noParent

public static final Binding noParent

Method Detail

create

public static BindingBuilder create()

create

public static BindingBuilder create(Binding parent)

set

public BindingBuilder set(Var var,
                          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,
                          Node node)

addAll

public BindingBuilder addAll(Binding other)

Add all the (var, value) pairs from another binding

getOrSame

public Node getOrSame(Var var)

Get or return the variable.

get

public Node get(Var var)

contains

public boolean contains(Var var)

isEmpty

public boolean isEmpty()

vars1

public java.util.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 java.lang.String toString()

Overrides:

toString in class java.lang.Object