Package org.h2.expression.function
Class JavaFunction
- java.lang.Object
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- org.h2.expression.Expression
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- org.h2.expression.function.JavaFunction
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- All Implemented Interfaces:
NamedExpression
,HasSQL
,Typed
public final class JavaFunction extends Expression implements NamedExpression
This class wraps a user-defined function.
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Field Summary
Fields Modifier and Type Field Description private Expression[]
args
private FunctionAlias
functionAlias
private FunctionAlias.JavaMethod
javaMethod
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Fields inherited from class org.h2.expression.Expression
AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES
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Fields inherited from interface org.h2.util.HasSQL
ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS
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Constructor Summary
Constructors Constructor Description JavaFunction(FunctionAlias functionAlias, Expression[] args)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
getCost()
Estimate the cost to process the expression.java.lang.String
getName()
Get the name.Expression
getSubexpression(int index)
Returns subexpression with specified index.int
getSubexpressionCount()
Returns count of subexpressions.TypeInfo
getType()
Returns the data type.java.lang.StringBuilder
getUnenclosedSQL(java.lang.StringBuilder builder, int sqlFlags)
Get the SQL statement of this expression.Value
getValue(SessionLocal session)
Return the resulting value for the current row.boolean
isEverything(ExpressionVisitor visitor)
Check if this expression and all sub-expressions can fulfill a criteria.void
mapColumns(ColumnResolver resolver, int level, int state)
Map the columns of the resolver to expression columns.Expression
optimize(SessionLocal session)
Try to optimize the expression.void
setEvaluatable(TableFilter tableFilter, boolean b)
Tell the expression columns whether the table filter can return values now.void
updateAggregate(SessionLocal session, int stage)
Update an aggregate value.-
Methods inherited from class org.h2.expression.Expression
addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimizeCondition, toString, writeExpressions, writeExpressions
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.h2.util.HasSQL
getTraceSQL
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Field Detail
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functionAlias
private final FunctionAlias functionAlias
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javaMethod
private final FunctionAlias.JavaMethod javaMethod
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args
private final Expression[] args
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Constructor Detail
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JavaFunction
public JavaFunction(FunctionAlias functionAlias, Expression[] args)
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Method Detail
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getValue
public Value getValue(SessionLocal session)
Description copied from class:Expression
Return the resulting value for the current row.- Specified by:
getValue
in classExpression
- Parameters:
session
- the session- Returns:
- the result
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getType
public TypeInfo getType()
Description copied from class:Expression
Returns the data type. The data type may be unknown before the optimization phase.- Specified by:
getType
in interfaceTyped
- Specified by:
getType
in classExpression
- Returns:
- the data type
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mapColumns
public void mapColumns(ColumnResolver resolver, int level, int state)
Description copied from class:Expression
Map the columns of the resolver to expression columns.- Specified by:
mapColumns
in classExpression
- Parameters:
resolver
- the column resolverlevel
- the subquery nesting levelstate
- current state for nesting checks, initial value isExpression.MAP_INITIAL
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optimize
public Expression optimize(SessionLocal session)
Description copied from class:Expression
Try to optimize the expression.- Specified by:
optimize
in classExpression
- Parameters:
session
- the session- Returns:
- the optimized expression
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setEvaluatable
public void setEvaluatable(TableFilter tableFilter, boolean b)
Description copied from class:Expression
Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.- Specified by:
setEvaluatable
in classExpression
- Parameters:
tableFilter
- the table filterb
- true if the table filter can return value
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getUnenclosedSQL
public java.lang.StringBuilder getUnenclosedSQL(java.lang.StringBuilder builder, int sqlFlags)
Description copied from class:Expression
Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.- Specified by:
getUnenclosedSQL
in classExpression
- Parameters:
builder
- string buildersqlFlags
- formatting flags- Returns:
- the specified string builder
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updateAggregate
public void updateAggregate(SessionLocal session, int stage)
Description copied from class:Expression
Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.- Specified by:
updateAggregate
in classExpression
- Parameters:
session
- the sessionstage
- select stage
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getName
public java.lang.String getName()
Description copied from interface:NamedExpression
Get the name.- Specified by:
getName
in interfaceNamedExpression
- Returns:
- the name in uppercase
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isEverything
public boolean isEverything(ExpressionVisitor visitor)
Description copied from class:Expression
Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.- Specified by:
isEverything
in classExpression
- Parameters:
visitor
- the visitor- Returns:
- if the criteria can be fulfilled
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getCost
public int getCost()
Description copied from class:Expression
Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.- Specified by:
getCost
in classExpression
- Returns:
- the estimated cost
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getSubexpressionCount
public int getSubexpressionCount()
Description copied from class:Expression
Returns count of subexpressions.- Overrides:
getSubexpressionCount
in classExpression
- Returns:
- count of subexpressions
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getSubexpression
public Expression getSubexpression(int index)
Description copied from class:Expression
Returns subexpression with specified index.- Overrides:
getSubexpression
in classExpression
- Parameters:
index
- 0-based index- Returns:
- subexpression with specified index, may be null
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