Package org.apache.commons.el
Class Coercions
- java.lang.Object
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- org.apache.commons.el.Coercions
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public class Coercions extends java.lang.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 BigDecimal, coerce both to BigDecimal and then: if operator is +, return
A.add(B)
if operator is -, returnA.subtract(B)
if operator is *, returnA.multiply(B)
if A or B is Float, Double, or String containing ".", "e", or "E" if A or B is BigInteger, coerce both A and B to BigDecimal and apply operator coerce both A and B to Double and apply operator if A or B is BigInteger, coerce both to BigInteger and then: if operator is +, returnA.add(B)
if operator is -, returnA.subtract(B)
if operator is *, returnA.multiply(B)
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 if A or B is a BigDecimal or BigInteger, coerce both to BigDecimal and returnA.divide(B, BigDecimal.ROUND_HALF_UP)
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 BigDecimal, Float, Double, or String containing ".", "e" or "E" coerce both to Double apply operator if A or B is BigInteger, coerce both to BigInteger and returnA.remainder(B)
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 BigInteger or BigDecimal, returnA.negate()
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 if A is Collection an ((Collection) 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 BigDecimal, coerce both A and B to BigDecimal and use the return value ofA.compareTo(B)
if A or B is Float or Double coerce both A and B to Double apply operator if A or B is BigInteger, coerce both A and B to BigInteger and use the return value ofA.compareTo(B)
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 BigDecimal, coerce both A and B to BigDecimal and then: if operator is == or eq, returnA.equals(B)
if operator is != or ne, return!A.equals(B)
if A or B is Float or Double coerce both A and B to Double apply operator if A or B is BigInteger, coerce both A and B to BigInteger and then: if operator is == or eq, returnA.equals(B)
if operator is != or ne, return!A.equals(B)
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 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, coerce quietly to type N using the following algorithm If N is BigInteger If A is BigDecimal, returnA.toBigInteger()
Otherwise, returnBigInteger.valueOf(A.longValue())
if N is BigDecimal If A is a BigInteger, returnnew BigDecimal(A)
Otherwise, returnnew BigDecimal(A.doubleValue())
If N is Byte, returnnew Byte(A.byteValue())
If N is Short, returnnew Short(A.shortValue())
If N is Integer, returnnew Integer(A.integerValue())
If N is Long, returnnew Long(A.longValue())
If N is Float, returnnew Float(A.floatValue())
If N is Double, returnnew Double(A.doubleValue())
otherwise ERROR A is String If N is BigDecimal then: Ifnew BigDecimal(A)
throws an exception then ERROR Otherwise, returnnew BigDecimal(A)
If N is BigInteger then: Ifnew BigInteger(A)
throws an exception, then ERROR Otherwise, returnnew BigInteger(A)
newN.valueOf(A)
throws exception error returnN.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- Version:
- $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
- Author:
- Nathan Abramson - Art Technology Group
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Field Summary
Fields Modifier and Type Field Description private static java.lang.Number
ZERO
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Constructor Summary
Constructors Constructor Description Coercions()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static java.lang.Object
applyArithmeticOperator(java.lang.Object pLeft, java.lang.Object pRight, ArithmeticOperator pOperator, Logger pLogger)
Performs all of the necessary type conversions, then calls on the appropriate operator.static java.lang.Object
applyEqualityOperator(java.lang.Object pLeft, java.lang.Object pRight, EqualityOperator pOperator, Logger pLogger)
Performs all of the necessary type conversions, then calls on the appropriate operator.static java.lang.Object
applyRelationalOperator(java.lang.Object pLeft, java.lang.Object pRight, RelationalOperator pOperator, Logger pLogger)
Performs all of the necessary type conversions, then calls on the appropriate operator.static java.lang.Object
coerce(java.lang.Object pValue, java.lang.Class pClass, Logger pLogger)
Coerces the given value to the specified class.static java.lang.Boolean
coerceToBoolean(java.lang.Object pValue, Logger pLogger)
Coerces a value to a Booleanstatic java.lang.Character
coerceToCharacter(java.lang.Object pValue, Logger pLogger)
Coerces a value to a Characterstatic java.lang.Integer
coerceToInteger(java.lang.Object pValue, Logger pLogger)
Coerces a value to an Integer, returning null if the coercion isn't possible.static java.lang.Object
coerceToObject(java.lang.Object pValue, java.lang.Class pClass, Logger pLogger)
Coerces a value to the specified Class that is not covered by any of the above cases(package private) static java.lang.Number
coerceToPrimitiveNumber(double pValue, java.lang.Class pClass)
Coerces a double to the given primitive number class(package private) static java.lang.Number
coerceToPrimitiveNumber(long pValue, java.lang.Class pClass)
Coerces a long to the given primitive number class(package private) static java.lang.Number
coerceToPrimitiveNumber(java.lang.Number pValue, java.lang.Class pClass)
Coerces a Number to the given primitive number classstatic java.lang.Number
coerceToPrimitiveNumber(java.lang.Object pValue, java.lang.Class pClass, Logger pLogger)
Coerces a value to the given primitive number class(package private) static java.lang.Number
coerceToPrimitiveNumber(java.lang.String pValue, java.lang.Class pClass)
Coerces a String to the given primitive number classstatic java.lang.String
coerceToString(java.lang.Object pValue, Logger pLogger)
Coerces the specified value to a Stringstatic boolean
isBigDecimal(java.lang.Object pObject)
Returns true if the given object is BigDecimal.static boolean
isBigInteger(java.lang.Object pObject)
Returns true if the given object is BigInteger.static boolean
isFloatingPointString(java.lang.Object pObject)
Returns true if the given string might contain a floating point number - i.e., it contains ".", "e", or "E"static boolean
isFloatingPointType(java.lang.Class pClass)
Returns true if the given class is of a floating point typestatic boolean
isFloatingPointType(java.lang.Object pObject)
Returns true if the given Object is of a floating point typestatic boolean
isIntegerType(java.lang.Class pClass)
Returns true if the given class is of an integer typestatic boolean
isIntegerType(java.lang.Object pObject)
Returns true if the given Object is of an integer type(package private) static boolean
isNumberClass(java.lang.Class pClass)
Returns true if the given class is Byte, Short, Integer, Long, Float, Double, BigInteger, or BigDecimal
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Method Detail
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coerce
public static java.lang.Object coerce(java.lang.Object pValue, java.lang.Class pClass, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces the given value to the specified class.- Throws:
javax.servlet.jsp.el.ELException
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isNumberClass
static boolean isNumberClass(java.lang.Class pClass)
Returns true if the given class is Byte, Short, Integer, Long, Float, Double, BigInteger, or BigDecimal
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coerceToString
public static java.lang.String coerceToString(java.lang.Object pValue, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces the specified value to a String- Throws:
javax.servlet.jsp.el.ELException
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coerceToPrimitiveNumber
public static java.lang.Number coerceToPrimitiveNumber(java.lang.Object pValue, java.lang.Class pClass, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces a value to the given primitive number class- Throws:
javax.servlet.jsp.el.ELException
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coerceToInteger
public static java.lang.Integer coerceToInteger(java.lang.Object pValue, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces a value to an Integer, returning null if the coercion isn't possible.- Throws:
javax.servlet.jsp.el.ELException
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coerceToPrimitiveNumber
static java.lang.Number coerceToPrimitiveNumber(long pValue, java.lang.Class pClass) throws javax.servlet.jsp.el.ELException
Coerces a long to the given primitive number class- Throws:
javax.servlet.jsp.el.ELException
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coerceToPrimitiveNumber
static java.lang.Number coerceToPrimitiveNumber(double pValue, java.lang.Class pClass) throws javax.servlet.jsp.el.ELException
Coerces a double to the given primitive number class- Throws:
javax.servlet.jsp.el.ELException
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coerceToPrimitiveNumber
static java.lang.Number coerceToPrimitiveNumber(java.lang.Number pValue, java.lang.Class pClass) throws javax.servlet.jsp.el.ELException
Coerces a Number to the given primitive number class- Throws:
javax.servlet.jsp.el.ELException
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coerceToPrimitiveNumber
static java.lang.Number coerceToPrimitiveNumber(java.lang.String pValue, java.lang.Class pClass) throws javax.servlet.jsp.el.ELException
Coerces a String to the given primitive number class- Throws:
javax.servlet.jsp.el.ELException
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coerceToCharacter
public static java.lang.Character coerceToCharacter(java.lang.Object pValue, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces a value to a Character- Throws:
javax.servlet.jsp.el.ELException
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coerceToBoolean
public static java.lang.Boolean coerceToBoolean(java.lang.Object pValue, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces a value to a Boolean- Throws:
javax.servlet.jsp.el.ELException
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coerceToObject
public static java.lang.Object coerceToObject(java.lang.Object pValue, java.lang.Class pClass, Logger pLogger) throws javax.servlet.jsp.el.ELException
Coerces a value to the specified Class that is not covered by any of the above cases- Throws:
javax.servlet.jsp.el.ELException
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applyArithmeticOperator
public static java.lang.Object applyArithmeticOperator(java.lang.Object pLeft, java.lang.Object pRight, ArithmeticOperator pOperator, Logger pLogger) throws javax.servlet.jsp.el.ELException
Performs all of the necessary type conversions, then calls on the appropriate operator.- Throws:
javax.servlet.jsp.el.ELException
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applyRelationalOperator
public static java.lang.Object applyRelationalOperator(java.lang.Object pLeft, java.lang.Object pRight, RelationalOperator pOperator, Logger pLogger) throws javax.servlet.jsp.el.ELException
Performs all of the necessary type conversions, then calls on the appropriate operator.- Throws:
javax.servlet.jsp.el.ELException
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applyEqualityOperator
public static java.lang.Object applyEqualityOperator(java.lang.Object pLeft, java.lang.Object pRight, EqualityOperator pOperator, Logger pLogger) throws javax.servlet.jsp.el.ELException
Performs all of the necessary type conversions, then calls on the appropriate operator.- Throws:
javax.servlet.jsp.el.ELException
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isFloatingPointType
public static boolean isFloatingPointType(java.lang.Object pObject)
Returns true if the given Object is of a floating point type
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isFloatingPointType
public static boolean isFloatingPointType(java.lang.Class pClass)
Returns true if the given class is of a floating point type
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isFloatingPointString
public static boolean isFloatingPointString(java.lang.Object pObject)
Returns true if the given string might contain a floating point number - i.e., it contains ".", "e", or "E"
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isIntegerType
public static boolean isIntegerType(java.lang.Object pObject)
Returns true if the given Object is of an integer type
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isIntegerType
public static boolean isIntegerType(java.lang.Class pClass)
Returns true if the given class is of an integer type
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isBigInteger
public static boolean isBigInteger(java.lang.Object pObject)
Returns true if the given object is BigInteger.- Parameters:
pObject
- - Object to evaluate- Returns:
- - true if the given object is BigInteger
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isBigDecimal
public static boolean isBigDecimal(java.lang.Object pObject)
Returns true if the given object is BigDecimal.- Parameters:
pObject
- - Object to evaluate- Returns:
- - true if the given object is BigDecimal
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