org.datanucleus.store.rdbms.sql.expression
Class SQLExpression

java.lang.Object
  org.datanucleus.store.rdbms.sql.expression.SQLExpression

Direct Known Subclasses:

ArrayExpression, BinaryExpression, BooleanExpression, CaseExpression, CharacterExpression, CollectionExpression, ColumnExpression, DelegatedExpression, MapExpression, MapLiteral.MapKeyLiteral, MapLiteral.MapValueLiteral, NewObjectExpression, NullLiteral, NumericExpression, ObjectExpression, ParameterLiteral, StringExpression, SubqueryExpression, TemporalExpression, UnboundExpression

public abstract class SQLExpression
extends Object

Base expression for SQL. The principle here is that any expression (be it a field, literal, parameter, variable etc) has a type and so needs a JavaTypeMapping to control reading/writing of that type. An expression will typically have an SQLTable (in the overall statement) that it refers to. A literal will not have an SQLTable since it represents a value. The actual SQL for the expression is embodied in the SQLText field. Construction typically sets the SQL for the respective expression.

Nested Class Summary

static class

SQLExpression.ColumnExpressionList

Field Summary

protected static org.datanucleus.util.Localiser	LOCALISER Localiser for messages
protected org.datanucleus.query.expression.Expression.Operator	lowestOperator
protected org.datanucleus.store.mapped.mapping.JavaTypeMapping	mapping Mapping for this expression, defining how it is get/set.
protected String	parameterName Parameter name that this represents (if this is a parameter, "?" in JDBC).
protected SQLText	st The Statement Text representing the SQL for this expression.
protected SQLStatement	stmt The SQL statement that this is part of.
protected SQLExpression.ColumnExpressionList	subExprs Sub-expressions, where we have a field with multiple columns for example.
protected SQLTable	table Table in the SQL statement that this mapping applies to.

Constructor Summary

protected	SQLExpression(org.datanucleus.query.expression.Expression.MonadicOperator op, SQLExpression expr1) Perform an operation "op" on expression "expr1".
protected	SQLExpression(SQLExpression expr1, org.datanucleus.query.expression.Expression.DyadicOperator op, SQLExpression expr2) Perform an operation "op" between "expr1" and "expr2".
protected	SQLExpression(SQLStatement stmt, org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping, String functionName, List<SQLExpression> args, List types) Generates statement as "FUNCTION_NAME(arg [AS type] [,argN [AS typeN]])".
protected	SQLExpression(SQLStatement stmt, SQLTable table, org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping) Constructor for an SQL expression for a (field) mapping in a specified table.

Method Summary

SQLExpression	add(SQLExpression expr) Additive Operator.
BooleanExpression	and(SQLExpression expr) Conditional And.
SQLExpression	cast(SQLExpression expr) A cast expression converts, at run time, a value of one type to a similar value of another type; or confirms, at compile time, that the type of an expression is boolean; or checks, at run time, that a reference value refers to an object whose class is compatible with a specified reference type.
SQLExpression	com() Bitwise Complement Operator
SQLExpression	distinct() Distinct operator.
SQLExpression	div(SQLExpression expr) Division Operator.
SQLExpression	encloseInParentheses() Method to request the enclosure of this expression within parentheses.
BooleanExpression	eor(SQLExpression expr) Exclusive OR
BooleanExpression	eq(SQLExpression expr) Equality operator (equals to)
BooleanExpression	ge(SQLExpression expr) Relational operator (greater than or equals)
org.datanucleus.store.mapped.mapping.JavaTypeMapping	getJavaTypeMapping()
org.datanucleus.query.expression.Expression.Operator	getLowestOperator()
int	getNumberOfSubExpressions()
String	getParameterName()
SQLStatement	getSQLStatement()
SQLTable	getSQLTable()
ColumnExpression	getSubExpression(int index)
BooleanExpression	gt(SQLExpression expr) Relational operator (greater than)
BooleanExpression	in(SQLExpression expr, boolean not) In expression.
SQLExpression	invoke(String methodName, List args) Invocation of a method on this expression.
BooleanExpression	ior(SQLExpression expr) Conditional OR.
BooleanExpression	is(SQLExpression expr, boolean not) An "is" (instanceOf) expression, providing a BooleanExpression whether this expression is an instanceof the provided type.
boolean	isParameter()
BooleanExpression	le(SQLExpression expr) Relational operator (lower than or equals)
BooleanExpression	lt(SQLExpression expr) Relational operator (lower than)
SQLExpression	mod(SQLExpression expr) Remainder Operator.
SQLExpression	mul(SQLExpression expr) Multiplication Operator
BooleanExpression	ne(SQLExpression expr) Not equality operator (not equals to)
SQLExpression	neg() Unary Minus Operator
BooleanExpression	not() Logical complement
void	setJavaTypeMapping(org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping)
SQLExpression	sub(SQLExpression expr) Additive Operator.
SQLText	toSQLText() Method to return the SQL form of this expression.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOCALISER

protected static final org.datanucleus.util.Localiser LOCALISER

Localiser for messages

stmt

protected SQLStatement stmt

The SQL statement that this is part of.

table

protected SQLTable table

Table in the SQL statement that this mapping applies to.

mapping

protected org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping

Mapping for this expression, defining how it is get/set.

st

protected final SQLText st

The Statement Text representing the SQL for this expression.

lowestOperator

protected org.datanucleus.query.expression.Expression.Operator lowestOperator

subExprs

protected SQLExpression.ColumnExpressionList subExprs

Sub-expressions, where we have a field with multiple columns for example.

parameterName

protected String parameterName

Parameter name that this represents (if this is a parameter, "?" in JDBC).

Constructor Detail

SQLExpression

protected SQLExpression(SQLStatement stmt,
                        SQLTable table,
                        org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping)

Constructor for an SQL expression for a (field) mapping in a specified table.

Parameters:

stmt - The statement

table - The table in the statement

mapping - The mapping for the field

SQLExpression

protected SQLExpression(org.datanucleus.query.expression.Expression.MonadicOperator op,
                        SQLExpression expr1)

Perform an operation "op" on expression "expr1".

Parameters:

op - operator

expr1 - operand

SQLExpression

protected SQLExpression(SQLExpression expr1,
                        org.datanucleus.query.expression.Expression.DyadicOperator op,
                        SQLExpression expr2)

Perform an operation "op" between "expr1" and "expr2".

Parameters:

expr1 - the first expression

op - the operator between operands

expr2 - the second expression

SQLExpression

protected SQLExpression(SQLStatement stmt,
                        org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping,
                        String functionName,
                        List<SQLExpression> args,
                        List types)

Generates statement as "FUNCTION_NAME(arg [AS type] [,argN [AS typeN]])". Number of objects in types (when supplied) is assumed to be the same as the number of arguments.

Parameters:

stmt - The statement to use for this expression

mapping - Mapping to use

functionName - Name of function

args - SQLExpression list

types - List of String/SQLExpression for the types of arguments

Method Detail

getLowestOperator

public org.datanucleus.query.expression.Expression.Operator getLowestOperator()

getNumberOfSubExpressions

public int getNumberOfSubExpressions()

getSubExpression

public ColumnExpression getSubExpression(int index)

getSQLStatement

public SQLStatement getSQLStatement()

isParameter

public boolean isParameter()

getParameterName

public String getParameterName()

getJavaTypeMapping

public org.datanucleus.store.mapped.mapping.JavaTypeMapping getJavaTypeMapping()

setJavaTypeMapping

public void setJavaTypeMapping(org.datanucleus.store.mapped.mapping.JavaTypeMapping mapping)

getSQLTable

public SQLTable getSQLTable()

toSQLText

public SQLText toSQLText()

Method to return the SQL form of this expression.

Returns:

The SQL

encloseInParentheses

public SQLExpression encloseInParentheses()

Method to request the enclosure of this expression within parentheses.

Returns:

the enclosed expression

and

public BooleanExpression and(SQLExpression expr)

Conditional And. Evaluates its right-hand operand only if the value of its left-hand operand is true.

Parameters:

expr - the right-hand operand

Returns:

the result value is true if both operand values are true; otherwise, the result is false.

eor

public BooleanExpression eor(SQLExpression expr)

Exclusive OR

Parameters:

expr - the right-hand operand

Returns:

the result value is the bitwise exclusive OR of the operand values.

ior

public BooleanExpression ior(SQLExpression expr)

Conditional OR. Evaluates its right-hand operand only if the value of its left-hand operand is false.

Parameters:

expr - the right-hand operand

Returns:

the result value is false if both operand values are false; otherwise, the result is true.

not

public BooleanExpression not()

Logical complement

Returns:

the result value is false if operand is true; otherwise, the result is true.

eq

public BooleanExpression eq(SQLExpression expr)

Equality operator (equals to)

Parameters:

expr - the right-hand operand

Returns:

The type of an equality expression is a boolean

ne

public BooleanExpression ne(SQLExpression expr)

Not equality operator (not equals to)

Parameters:

expr - the right-hand operand

Returns:

The type of an equality expression is a boolean

lt

public BooleanExpression lt(SQLExpression expr)

Relational operator (lower than)

Parameters:

expr - the right-hand operand

Returns:

true if the value of the left-hand operand is less than the value of the right-hand operand, and otherwise is false.

le

public BooleanExpression le(SQLExpression expr)

Relational operator (lower than or equals)

Parameters:

expr - the right-hand operand

Returns:

true if the value of the left-hand operand is less than or equal to the value of the right-hand operand, and otherwise is false.

gt

public BooleanExpression gt(SQLExpression expr)

Relational operator (greater than)

Parameters:

expr - the right-hand operand

Returns:

true if the value of the left-hand operand is greater than the value of the right-hand operand, and otherwise is false.

ge

public BooleanExpression ge(SQLExpression expr)

Relational operator (greater than or equals)

Parameters:

expr - the right-hand operand

Returns:

true if the value of the left-hand operand is greater than or equal the value of the right-hand operand, and otherwise is false.

in

public BooleanExpression in(SQLExpression expr,
                            boolean not)

In expression. Return true if this is contained by expr

Parameters:

expr - the right-hand expression

not - Whether we really want "not in"

Returns:

true if the left-hand expression is contained by the right-hand expression. Otherwise the result is false.

add

public SQLExpression add(SQLExpression expr)

Additive Operator. The binary + operator performs addition when applied to two operands of numeric type, producing the sum of the operands. If the type of either operand of a + operator is String, then the operation is string concatenation.

Parameters:

expr - the right-hand operand

Returns:

If one of the operands is String, the returned value is the string concatenation; The sum of two operands of numeric type. The left-hand operand is the minuend and the right-hand operand is the subtrahend;

sub

public SQLExpression sub(SQLExpression expr)

Additive Operator. The binary - operator subtracts right-hand operand from left-hand operand.

Parameters:

expr - the right-hand operand

Returns:

The binary - operator performs subtraction when applied to two operands of numeric type producing the difference of its operands; the left-hand operand is the minuend and the right-hand operand is the subtrahend.

mul

public SQLExpression mul(SQLExpression expr)

Multiplication Operator

Parameters:

expr - the right-hand operator

Returns:

The binary * operator performs multiplication, producing the product of its operands.

div

public SQLExpression div(SQLExpression expr)

Division Operator. The left-hand operand is the dividend and the right-hand operand is the divisor.

Parameters:

expr - the right-hand operator

Returns:

The binary / operator performs division, producing the quotient of its operands

mod

public SQLExpression mod(SQLExpression expr)

Remainder Operator. The left-hand operand is the dividend and the right-hand operand is the divisor.

Parameters:

expr - the right-hand operator

Returns:

The binary % operator is said to yield the remainder of its operands from an implied division

neg

public SQLExpression neg()

Unary Minus Operator

Returns:

the type of the unary minus expression is the promoted type of the operand.

com

public SQLExpression com()

Bitwise Complement Operator

Returns:

the type of the unary bitwise complement expression is the promoted type of the operand.

distinct

public SQLExpression distinct()

Distinct operator.

Returns:

converts the expression into "DISTINCT (expr)"

cast

public SQLExpression cast(SQLExpression expr)

A cast expression converts, at run time, a value of one type to a similar value of another type; or confirms, at compile time, that the type of an expression is boolean; or checks, at run time, that a reference value refers to an object whose class is compatible with a specified reference type. The type of the operand expression must be converted to the type explicitly named by the cast operator.

Parameters:

expr - expression representing the type to cast to

Returns:

the converted value

is

public BooleanExpression is(SQLExpression expr,
                            boolean not)

An "is" (instanceOf) expression, providing a BooleanExpression whether this expression is an instanceof the provided type.

Parameters:

expr - the expression representing the type

not - Whether we really want "!instanceof"

Returns:

Whether this expression is an instance of the provided type

invoke

public SQLExpression invoke(String methodName,
                            List args)

Invocation of a method on this expression.

Parameters:

methodName - name of the method to invoke

args - Args to this method (if any)

Returns:

the converted value