org.josql.expressions

类 BindVariable

java.lang.Object

org.josql.expressions.Expression

org.josql.expressions.ValueExpression

org.josql.expressions.BindVariable

public class BindVariable
extends ValueExpression

字段概要

字段

限定符和类型	字段和说明
static String	SPECIAL_NAME_PREFIX

构造器概要

构造器

构造器和说明
BindVariable()

方法概要

限定符和类型	方法和说明
boolean	equals(Object o)
Object	evaluate(Object o, Query q) Evaluates the value of this bind variable.
String	getAccessor()
Class	getExpectedReturnType(Query q) Get the expected return type.
String	getName()
Object	getValue(Object o, Query q) Gets the value of this bind variable.
boolean	hasFixedResult(Query q) Will always return false since a bind variable cannot be fixed.
void	init(Query q) Initialises this bind variable.
boolean	isAnonymous()
boolean	isTrue(Object o, Query q) Returns whether the value of this bind variable represents a true value.
void	setAccessor(String a)
void	setAnonymous(boolean v)
void	setName(String name)
String	toString() Returns a string version of this bind variable.

从类继承的方法 org.josql.expressions.Expression

isBracketed, setBracketed

从类继承的方法 java.lang.Object

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

字段详细资料

SPECIAL_NAME_PREFIX

public static final String SPECIAL_NAME_PREFIX

另请参阅:

常量字段值

构造器详细资料

BindVariable

public BindVariable()

方法详细资料

equals

public boolean equals(Object o)

覆盖:

equals 在类中 Object

getAccessor

public String getAccessor()

setAccessor

public void setAccessor(String a)

getExpectedReturnType

public Class getExpectedReturnType(Query q)
                            throws QueryParseException

Get the expected return type. The exact class returned here is dependent (obviously) on what the bind variable represents. Wherever possible it attempts to get the most specific class for the variable. It is generally better to set the variables prior to executing the: Query.parse(String) method to ensure that the correct class is returned here.

指定者:

getExpectedReturnType 在类中 Expression

参数:

q - The Query object.

返回:

The return type class or java.lang.Object.class if the class cannot be determined.

抛出:

QueryParseException - If the type cannot be determined.

init

public void init(Query q)
          throws QueryParseException

Initialises this bind variable. If the bind variable is "anonymous" then a name is gained for it from the Query object. If there is a value then it is gained from the Query object and cached. Also, if there is an accessor defined then it is inited where possible.

指定者:

init 在类中 Expression

参数:

q - The Query object.

抛出:

QueryParseException - If the bind variable cannot be inited.

getName

public String getName()

isAnonymous

public boolean isAnonymous()

setAnonymous

public void setAnonymous(boolean v)

setName

public void setName(String name)

getValue

public Object getValue(Object o,
                       Query q)
                throws QueryExecutionException

Gets the value of this bind variable.

覆盖:

getValue 在类中 ValueExpression

参数:

o - The current object. Note that this variable isn't used in this method.

q - The Query object.

返回:

The value.

抛出:

QueryExecutionException - If something goes wrong during the accessing of the value.

isTrue

public boolean isTrue(Object o,
                      Query q)
               throws QueryExecutionException

Returns whether the value of this bind variable represents a true value. See: ArithmeticExpression.isTrue(Object,Query) for details of how the return value is determined.

指定者:

isTrue 在类中 Expression

参数:

o - The current object. Not used in this method.

q - The Query object.

返回:

true if the bind variable evaluates to true.

抛出:

QueryExecutionException - If a problem occurs during evaluation.

evaluate

public Object evaluate(Object o,
                       Query q)
                throws QueryExecutionException

Evaluates the value of this bind variable. This is just a thin-wrapper around: getValue(Object,Query).

指定者:

evaluate 在类中 ValueExpression

参数:

o - The current object, not used in this method.

q - The Query object.

返回:

The value of this bind variable.

抛出:

QueryExecutionException - If there is a problem getting the value.

toString

public String toString()

Returns a string version of this bind variable. Returns in the form: ? | ":" [ "_" ] Name

指定者:

toString 在类中 Expression

返回:

A string version of the bind variable.

hasFixedResult

public boolean hasFixedResult(Query q)

Will always return false since a bind variable cannot be fixed.

指定者:

hasFixedResult 在类中 Expression

参数:

q - The Query object.

返回:

false always.