com.espertech.esper.client.soda

Class CoalesceExpression

java.lang.Object

com.espertech.esper.client.soda.ExpressionBase

com.espertech.esper.client.soda.CoalesceExpression

All Implemented Interfaces:

Expression, Serializable

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

Constructors

Constructor and Description
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

Modifier and Type	Method and Description
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.
ExpressionPrecedenceEnum	getPrecedence() Returns precedence.
void	toPrecedenceFreeEPL(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 com.espertech.esper.client.soda.ExpressionBase

addChild, getChildren, getTreeObjectName, renderAggregation, setChildren, setTreeObjectName, toEPL, toPrecedenceFreeEPL, toPrecedenceFreeEPL

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

getPrecedence

public ExpressionPrecedenceEnum getPrecedence()

Description copied from interface: Expression

Returns precedence.

Returns:

precedence

toPrecedenceFreeEPL

public void toPrecedenceFreeEPL(StringWriter writer)

Description copied from class: ExpressionBase

Renders the expressions and all it's child expression, in full tree depth, as a string in language syntax.

Specified by:

toPrecedenceFreeEPL in class ExpressionBase

Parameters:

writer - is the output to use