org.josql.expressions

类 Accessor

java.lang.Object

org.josql.expressions.Expression

org.josql.expressions.ValueExpression

org.josql.expressions.Accessor

public class Accessor
extends ValueExpression

构造器概要

构造器

构造器和说明
Accessor()

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)
String	getAccessor()
Class	getExpectedReturnType(Query q) Return the class of the object that "should" be returned from a call to the: Expression.getValue(Object,Query) method.
Getter	getGetter()
boolean	hasFixedResult(Query q) Return whether the expression will evaluate to a fixed/constant result.
void	init(Query q) Perform the necessary initialisation for this expression.
boolean	isTrue(Object o, Query q) This method allows ANY expression (including those that extend ValueExpression) to be used in the WHERE and HAVING clauses but ensuring that a boolean value is available for every expression.
void	setAccessor(String a)
void	setName(String name)
String	toString() Return a string representation of the expression, making this abstract forces sub-classes to provide an implementation.

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

getValue

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

构造器详细资料

Accessor

public Accessor()

方法详细资料

getExpectedReturnType

public Class getExpectedReturnType(Query q)
                            throws QueryParseException

从类复制的说明: Expression

Return the class of the object that "should" be returned from a call to the: Expression.getValue(Object,Query) method. It may be that repeated executions of a query will return different classes from this method. In general sub-classes should take this variance into account.

指定者:

getExpectedReturnType 在类中 Expression

参数:

q - The Query object.

返回:

The expected type that will be returned from the Expression.getValue(Object,Query) method.

抛出:

QueryParseException - If something goes wrong with determining the type.

init

public void init(Query q)
          throws QueryParseException

从类复制的说明: Expression

Perform the necessary initialisation for this expression. The exact operations performed are defined by the sub-class.

指定者:

init 在类中 Expression

参数:

q - The Query object.

抛出:

QueryParseException - If something goes wrong with the initialisation.

getAccessor

public String getAccessor()

setAccessor

public void setAccessor(String a)

getGetter

public Getter getGetter()

setName

public void setName(String name)

isTrue

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

从类复制的说明: Expression

This method allows ANY expression (including those that extend ValueExpression) to be used in the WHERE and HAVING clauses but ensuring that a boolean value is available for every expression.

指定者:

isTrue 在类中 Expression

参数:

o - The current object to evaluate the expression on.

q - The Query object.

返回:

true if the expression evaluates to true (well duh...).

抛出:

QueryExecutionException - If there is a problem with the execution of the expression.

hasFixedResult

public boolean hasFixedResult(Query q)

从类复制的说明: Expression

Return whether the expression will evaluate to a fixed/constant result. This allows certain optimisations to be performed when an expression is evaluated. A "fixed result" is basically one in which multiple calls to either the: Expression.isTrue(Object,Query) or Expression.getValue(Object,Query) methods will return the same object (or that o1.equals (o2) == true) regardless of the object passed to the method.

指定者:

hasFixedResult 在类中 Expression

参数:

q - The Query object.

返回:

true if the expression evaluates to a fixed/constant result.

evaluate

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

指定者:

evaluate 在类中 ValueExpression

抛出:

QueryExecutionException

equals

public boolean equals(Object o)

覆盖:

equals 在类中 Object

toString

public String toString()

从类复制的说明: Expression

Return a string representation of the expression, making this abstract forces sub-classes to provide an implementation.

指定者:

toString 在类中 Expression

返回:

A string representation of the expression.