Package org.eclipse.rdf4j.query.algebra

## Class Union

- java.lang.Object
- - org.eclipse.rdf4j.query.algebra.AbstractQueryModelNode
  - - org.eclipse.rdf4j.query.algebra.BinaryTupleOperator
    - - org.eclipse.rdf4j.query.algebra.Union

- All Implemented Interfaces:
    `Serializable`, `Cloneable`, `GraphPatternGroupable`, `QueryModelNode`, `TupleExpr`, `VariableScopeChange`

      public class Union
      extends BinaryTupleOperator

  The UNION set operator, which return the union of the result sets of two tuple expressions.
  See Also:
    Serialized Form

- - ### Field Summary

    - ### Fields inherited from class org.eclipse.rdf4j.query.algebra.BinaryTupleOperator

      `leftArg, rightArg`

  - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `Union()` |
    `Union​(TupleExpr leftArg, TupleExpr rightArg)` | Creates a new union operator that operates on the two specified arguments.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `Union` | `clone()` | Returns a (deep) clone of this query model node.
    `boolean` | `equals​(Object other)` | Returns true if this query model node and its children are recursively equal to o and its children.
    `Set<String>` | `getAssuredBindingNames()` | Gets the names of the bindings that are guaranteed to be present in the results produced by this tuple expression.
    `Set<String>` | `getBindingNames()` | Gets the names of the bindings that are, or can be, returned by this tuple expression when it is evaluated.
    `int` | `hashCode()` |
    `<X extends Exception> void` | `visit​(QueryModelVisitor<X> visitor)` | Visits this node.

    - ### Methods inherited from class org.eclipse.rdf4j.query.algebra.BinaryTupleOperator

      `getAlgorithmName, getLeftArg, getRightArg, replaceChildNode, setAlgorithm, setLeftArg, setRightArg, visitChildren`

    - ### Methods inherited from class org.eclipse.rdf4j.query.algebra.AbstractQueryModelNode

      `getCostEstimate, getParentNode, getResultSizeActual, getResultSizeEstimate, getSignature, getTotalTimeNanosActual, isGraphPatternGroup, isVariableScopeChange, nullEquals, replaceNodeInList, replaceWith, setCostEstimate, setGraphPatternGroup, setParentNode, setResultSizeActual, setResultSizeEstimate, setTotalTimeNanosActual, setVariableScopeChange, toString`

    - ### Methods inherited from class java.lang.Object

      `finalize, getClass, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface org.eclipse.rdf4j.query.algebra.QueryModelNode

      `getCostEstimate, getParentNode, getResultSizeActual, getResultSizeEstimate, getSignature, getTotalTimeNanosActual, replaceWith, setCostEstimate, setParentNode, setResultSizeActual, setResultSizeEstimate, setTotalTimeNanosActual, toString`

- - ### Constructor Detail

    - #### Union

          public Union()

    - #### Union

          public Union​(TupleExpr leftArg,
                       TupleExpr rightArg)

      Creates a new union operator that operates on the two specified arguments.
      Parameters:
        `leftArg` - The left argument of the union operator.
        `rightArg` - The right argument of the union operator.

  - ### Method Detail

    - #### getBindingNames

          public Set<String> getBindingNames()

      Description copied from interface: `TupleExpr`
      Gets the names of the bindings that are, or can be, returned by this tuple expression when it is evaluated.
      Returns:
        A set of binding names.

    - #### getAssuredBindingNames

          public Set<String> getAssuredBindingNames()

      Description copied from interface: `TupleExpr`
      Gets the names of the bindings that are guaranteed to be present in the results produced by this tuple expression.
      Returns:
        A set of binding names.

    - #### visit

          public <X extends Exception> void visit​(QueryModelVisitor<X> visitor)
                                           throws X extends Exception

      Description copied from interface: `QueryModelNode`
      Visits this node. The node reports itself to the visitor with the proper runtime type.
      Throws:
        `X extends Exception`

    - #### equals

          public boolean equals​(Object other)

      Description copied from interface: `QueryModelNode`
      Returns true if this query model node and its children are recursively equal to o and its children.
      Specified by:
        `equals` in interface `QueryModelNode`
      Overrides:
        `equals` in class `BinaryTupleOperator`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `BinaryTupleOperator`

    - #### clone

          public Union clone()

      Description copied from interface: `QueryModelNode`
      Returns a (deep) clone of this query model node. This method recursively clones the entire node tree, starting from this nodes.
      Specified by:
        `clone` in interface `QueryModelNode`
      Specified by:
        `clone` in interface `TupleExpr`
      Overrides:
        `clone` in class `BinaryTupleOperator`
      Returns:
        A deep clone of this query model node.