net.esper.client.soda
Class CoalesceExpression

java.lang.Object
  extended by net.esper.client.soda.ExpressionBase
      extended by net.esper.client.soda.CoalesceExpression
All Implemented Interfaces:
Serializable, Expression

public class CoalesceExpression
extends ExpressionBase

Coalesce-function which returns the first non-null value in a list of values.

See Also:
Serialized Form

Constructor Summary
CoalesceExpression()
          Ctor - for use to create an expression tree, without child expression.
CoalesceExpression(Expression exprOne, Expression exprTwo, Expression... moreExpressions)
          Ctor.
CoalesceExpression(String propertyOne, String propertyTwo, String... moreProperties)
          Ctor.
 
Method Summary
 CoalesceExpression add(Expression expression)
          Add an expression to include in the computation.
 CoalesceExpression add(Object object)
          Add a constant to include in the computation.
 CoalesceExpression add(String propertyName)
          Add a property to include in the computation.
 void toEQL(StringWriter writer)
          Renders the expressions and all it's child expression, in full tree depth, as a string in language syntax.
 
Methods inherited from class net.esper.client.soda.ExpressionBase
addChild, getChildren
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

CoalesceExpression

public CoalesceExpression()
Ctor - for use to create an expression tree, without child expression.

Use add methods to add child expressions to acts upon.


CoalesceExpression

public CoalesceExpression(String propertyOne,
                          String propertyTwo,
                          String... moreProperties)
Ctor.

Parameters:
propertyOne - the first property in the expression
propertyTwo - the second property in the expression
moreProperties - optional more properties in the expression

CoalesceExpression

public CoalesceExpression(Expression exprOne,
                          Expression exprTwo,
                          Expression... moreExpressions)
Ctor.

Parameters:
exprOne - provides the first value in the expression
exprTwo - provides the second value in the expression
moreExpressions - optional more expressions that are part of the function
Method Detail

add

public CoalesceExpression add(Object object)
Add a constant to include in the computation.

Parameters:
object - constant to add
Returns:
expression

add

public CoalesceExpression add(Expression expression)
Add an expression to include in the computation.

Parameters:
expression - to add
Returns:
expression

add

public CoalesceExpression add(String propertyName)
Add a property to include in the computation.

Parameters:
propertyName - is the name of the property
Returns:
expression

toEQL

public void toEQL(StringWriter writer)
Description copied from interface: Expression
Renders the expressions and all it's child expression, in full tree depth, as a string in language syntax.

Parameters:
writer - is the output to use

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