public class Coercions extends Object
This class contains the logic for coercing data types before operators are applied to them.
The following is the list of rules applied for various type conversions.
Applying arithmetic operator
Binary operator - A {+,-,*} B
if A and B are null
return 0
if A or B is Float, Double, or String containing ".", "e", or "E"
coerce both A and B to Double
apply operator
otherwise
coerce both A and B to Long
apply operator
if operator results in exception (such as divide by 0), error
Binary operator - A {/,div} B
if A and B are null
return 0
otherwise
coerce both A and B to Double
apply operator
if operator results in exception (such as divide by 0), error
Binary operator - A {%,mod} B
if A and B are null
return 0
if A or B is Float, Double, or String containing ".", "e" or "E"
coerce both to Double
apply operator
otherwise
coerce both A and B to Long
apply operator
if operator results in exception (such as divide by 0), error
Unary minus operator - -A
if A is null
return 0
if A is String
if A contains ".", "e", or "E"
coerce to Double, apply operator
otherwise
coerce to a Long and apply operator
if A is Byte,Short,Integer,Long,Float,Double
retain type, apply operator
if operator results in exception, error
otherwise
error
Applying "empty" operator - empty A
if A is null
return true
if A is zero-length String
return true
if A is zero-length array
return true
if A is List and ((List) A).isEmpty()
return true
if A is Map and ((Map) A).isEmpty()
return true
otherwise
return false
Applying logical operators
Binary operator - A {and,or} B
coerce both A and B to Boolean, apply operator
NOTE - operator stops as soon as expression can be determined, i.e.,
A and B and C and D - if B is false, then only A and B is evaluated
Unary not operator - not A
coerce A to Boolean, apply operator
Applying relational operator
A {<,>,<=,>=,lt,gt,lte,gte} B
if A==B
if operator is >= or <=
return true
otherwise
return false
if A or B is null
return false
if A or B is Float or Double
coerce both A and B to Double
apply operator
if A or B is Byte,Short,Character,Integer,Long
coerce both A and B to Long
apply operator
if A or B is String
coerce both A and B to String, compare lexically
if A is Comparable
if A.compareTo (B) throws exception
error
otherwise
use result of A.compareTo(B)
if B is Comparable
if B.compareTo (A) throws exception
error
otherwise
use result of B.compareTo(A)
otherwise
error
Applying equality operator
A {==,!=} B
if A==B
apply operator
if A or B is null
return false for ==, true for !=
if A or B is Float or Double
coerce both A and B to Double
apply operator
if A or B is Byte,Short,Character,Integer,Long
coerce both A and B to Long
apply operator
if A or B is Boolean
coerce both A and B to Boolean
apply operator
if A or B is String
coerce both A and B to String, compare lexically
otherwise
if an error occurs while calling A.equals(B)
error
apply operator to result of A.equals(B)
coercions
coerce A to String
A is String
return A
A is null
return ""
A.toString throws exception
error
otherwise
return A.toString
coerce A to primitive Number type N
A is null or ""
return 0
A is Character
convert to short, apply following rules
A is Boolean
error
A is Number type N
return A
A is Number with less precision than N
coerce quietly
A is Number with greater precision than N
coerce quietly
A is String
new N.valueOf(A) throws exception
error
return N.valueOf(A)
otherwise
error
coerce A to Character should be
A is null or ""
return (char) 0
A is Character
return A
A is Boolean
error
A is Number with less precision than short
coerce quietly - return (char) A
A is Number with greater precision than short
coerce quietly - return (char) A
A is String
return A.charAt (0)
otherwise
error
coerce A to Boolean
A is null or ""
return false
A is Boolean
return A
A is String
Boolean.valueOf(A) throws exception
error
return Boolean.valueOf(A)
otherwise
error
coerce A to any other type T
A is null
return null
A is assignable to T
coerce quietly
A is String
T has no PropertyEditor
if A is "", return null
otherwise error
T's PropertyEditor throws exception
if A is "", return null
otherwise error
otherwise
apply T's PropertyEditor
otherwise
error
| Constructor and Description |
|---|
Coercions() |
| Modifier and Type | Method and Description |
|---|---|
static Object |
applyArithmeticOperator(Object pLeft,
Object pRight,
ArithmeticOperator pOperator,
Logger pLogger)
Performs all of the necessary type conversions, then calls on the
appropriate operator.
|
static Object |
applyEqualityOperator(Object pLeft,
Object pRight,
EqualityOperator pOperator,
Logger pLogger)
Performs all of the necessary type conversions, then calls on the
appropriate operator.
|
static Object |
applyRelationalOperator(Object pLeft,
Object pRight,
RelationalOperator pOperator,
Logger pLogger)
Performs all of the necessary type conversions, then calls on the
appropriate operator.
|
static Object |
coerce(Object pValue,
Class pClass,
Logger pLogger)
Coerces the given value to the specified class.
|
static Boolean |
coerceToBoolean(Object pValue,
Logger pLogger)
Coerces a value to a Boolean
|
static Character |
coerceToCharacter(Object pValue,
Logger pLogger)
Coerces a value to a Character
|
static Integer |
coerceToInteger(Object pValue,
Logger pLogger)
Coerces a value to an Integer, returning null if the coercion
isn't possible.
|
static Object |
coerceToObject(Object pValue,
Class pClass,
Logger pLogger)
Coerces a value to the specified Class that is not covered by any
of the above cases
|
static Number |
coerceToPrimitiveNumber(Object pValue,
Class pClass,
Logger pLogger)
Coerces a value to the given primitive number class
|
static String |
coerceToString(Object pValue,
Logger pLogger)
Coerces the specified value to a String
|
static boolean |
isFloatingPointString(Object pObject)
Returns true if the given string might contain a floating point
number - i.e., it contains ".", "e", or "E"
|
static boolean |
isFloatingPointType(Class pClass)
Returns true if the given class is of a floating point type
|
static boolean |
isFloatingPointType(Object pObject)
Returns true if the given Object is of a floating point type
|
static boolean |
isIntegerType(Class pClass)
Returns true if the given class is of an integer type
|
static boolean |
isIntegerType(Object pObject)
Returns true if the given Object is of an integer type
|
public static Object coerce(Object pValue, Class pClass, Logger pLogger) throws ELException
ELExceptionpublic static String coerceToString(Object pValue, Logger pLogger) throws ELException
ELExceptionpublic static Number coerceToPrimitiveNumber(Object pValue, Class pClass, Logger pLogger) throws ELException
ELExceptionpublic static Integer coerceToInteger(Object pValue, Logger pLogger) throws ELException
ELExceptionpublic static Character coerceToCharacter(Object pValue, Logger pLogger) throws ELException
ELExceptionpublic static Boolean coerceToBoolean(Object pValue, Logger pLogger) throws ELException
ELExceptionpublic static Object coerceToObject(Object pValue, Class pClass, Logger pLogger) throws ELException
ELExceptionpublic static Object applyArithmeticOperator(Object pLeft, Object pRight, ArithmeticOperator pOperator, Logger pLogger) throws ELException
ELExceptionpublic static Object applyRelationalOperator(Object pLeft, Object pRight, RelationalOperator pOperator, Logger pLogger) throws ELException
ELExceptionpublic static Object applyEqualityOperator(Object pLeft, Object pRight, EqualityOperator pOperator, Logger pLogger) throws ELException
ELExceptionpublic static boolean isFloatingPointType(Object pObject)
public static boolean isFloatingPointType(Class pClass)
public static boolean isFloatingPointString(Object pObject)
public static boolean isIntegerType(Object pObject)
public static boolean isIntegerType(Class pClass)
Copyright © 2016 JBoss by Red Hat. All rights reserved.