org.jsimpledb.parse.expr

Class FieldValue

java.lang.Object

org.jsimpledb.parse.expr.AbstractValue

org.jsimpledb.parse.expr.FieldValue

All Implemented Interfaces:

Value

Direct Known Subclasses:

SimpleFieldValue

public class FieldValue
extends AbstractValue

Value that reflects a core API Field in some database object.

See Also:

JFieldValue

Field Summary

Fields

Modifier and Type	Field and Description
protected Field<?>	field
protected ObjId	id

Fields inherited from interface org.jsimpledb.parse.expr.Value

EQ, GT, LT, NO_VALUE

Constructor Summary

Constructors

Constructor and Description
FieldValue(ObjId id, Field<?> field) Constructor.

Method Summary

Modifier and Type	Method and Description
Object	get(ParseSession session) Evaluate this value within the given context.
Class<?>	getType(ParseSession session) Get the type of this value without evaluating it.

Methods inherited from class org.jsimpledb.parse.expr.AbstractValue

add, and, asLValue, checkBoolean, checkIntegral, checkNotNull, checkNumeric, checkType, compare, divide, invert, lshift, mod, multiply, negate, or, rshift, subtract, urshift, xor, xxcrement

Methods inherited from class java.lang.Object

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

Field Detail

id

protected final ObjId id

field

protected final Field<?> field

Constructor Detail

FieldValue

public FieldValue(ObjId id,
                  Field<?> field)

Constructor.

Parameters:

id - object ID

field - database field

Throws:

IllegalArgumentException - if id is null

IllegalArgumentException - if field is null

Method Detail

get

public Object get(ParseSession session)

Description copied from interface: Value

Evaluate this value within the given context.

Normally this method should only be invoked once, and the result cached, because evaluation could have side effects.

Parameters:

session - parse session

Returns:

the evaluated result

getType

public Class<?> getType(ParseSession session)

Description copied from interface: Value

Get the type of this value without evaluating it.

This should perform a best-effort attempt to determine the type, but should not invoke get(). If the type is unknown, Object.class should be returned.

Specified by:

getType in interface Value

Overrides:

getType in class AbstractValue

Parameters:

session - parse session

Returns:

the expected type of the evaluated result