org.apache.flink.table.expressions

类 ValueLiteralExpression

java.lang.Object

org.apache.flink.table.expressions.ValueLiteralExpression

所有已实现的接口:

Expression, ResolvedExpression

@PublicEvolving
public final class ValueLiteralExpression
extends Object
implements ResolvedExpression

Expression for constant literal values.

By design, this class can take any value described by a DataType. However, it is recommended to use instances with default conversion (see DataType.getConversionClass().

Equals/hashCode support of this expression depends on the equals/hashCode support of the value.

The data type can be extracted automatically from non-null values using value-based extraction (see ValueDataTypeConverter).

Symbols (enums extending from TableSymbol) are considered as literal values.

构造器概要

构造器

构造器和说明
ValueLiteralExpression(Object value)
ValueLiteralExpression(Object value, DataType dataType)

方法概要

限定符和类型	方法和说明
<R> R	accept(ExpressionVisitor<R> visitor)
String	asSummaryString() Returns a string that summarizes this expression for printing to a console.
boolean	equals(Object o)
List<Expression>	getChildren()
DataType	getOutputDataType() Returns the data type of the computation result.
List<ResolvedExpression>	getResolvedChildren()
<T> Optional<T>	getValueAs(Class<T> clazz) Returns the value (excluding null) as an instance of the given class.
int	hashCode()
boolean	isNull()
String	toString()

从类继承的方法 java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

从接口继承的方法 org.apache.flink.table.expressions.ResolvedExpression

asSerializableString

构造器详细资料

ValueLiteralExpression

public ValueLiteralExpression(@Nonnull
                              Object value)

ValueLiteralExpression

public ValueLiteralExpression(@Nullable
                              Object value,
                              DataType dataType)

方法详细资料

isNull

public boolean isNull()

getValueAs

public <T> Optional<T> getValueAs(Class<T> clazz)

Returns the value (excluding null) as an instance of the given class.

It supports conversions to default conversion classes of LogicalTypes and additionally to BigDecimal for all types of LogicalTypeFamily.NUMERIC. This method should not be called with other classes.

Note to implementers: Whenever we add a new class here, make sure to also update the planner for supporting the class via CallContext.getArgumentValue(int, Class).

getOutputDataType

public DataType getOutputDataType()

从接口复制的说明: ResolvedExpression

Returns the data type of the computation result.

指定者:

getOutputDataType 在接口中 ResolvedExpression

getResolvedChildren

public List<ResolvedExpression> getResolvedChildren()

指定者:

getResolvedChildren 在接口中 ResolvedExpression

asSummaryString

public String asSummaryString()

从接口复制的说明: Expression

Returns a string that summarizes this expression for printing to a console. An implementation might skip very specific properties.

指定者:

asSummaryString 在接口中 Expression

返回:

summary string of this expression for debugging purposes

getChildren

public List<Expression> getChildren()

指定者:

getChildren 在接口中 Expression

accept

public <R> R accept(ExpressionVisitor<R> visitor)

指定者:

accept 在接口中 Expression

equals

public boolean equals(Object o)

覆盖:

equals 在类中 Object

hashCode

public int hashCode()

覆盖:

hashCode 在类中 Object

toString

public String toString()

覆盖:

toString 在类中 Object