ELSupport (Apache Tomcat 8.0.53 API Documentation)

java.lang.Object
- org.apache.el.lang.ELSupport

Direct Known Subclasses:

SimpleNode
```
public class ELSupport
extends java.lang.Object
```
A helper class that implements the EL Specification

Author:

Jacob Hookom [jacob@hookom.net]

Field Summary

Fields
Modifier and Type Field and Description

protected static boolean COERCE_TO_ZERO

Fields
Modifier and Type	Field and Description
`protected static boolean`	`COERCE_TO_ZERO`

Constructor Summary

Constructors
Constructor and Description

ELSupport()

Constructors
Constructor and Description
`ELSupport()`

Method Summary

Methods
Modifier and Type	Method and Description
`static java.lang.Boolean`	`coerceToBoolean(ELContext ctx, java.lang.Object obj, boolean primitive)` Convert an object to Boolean.
`static java.lang.Enum<?>`	`coerceToEnum(ELContext ctx, java.lang.Object obj, java.lang.Class type)`
`static java.lang.Number`	`coerceToNumber(ELContext ctx, java.lang.Object obj, java.lang.Class<?> type)`
`protected static java.lang.Number`	`coerceToNumber(java.lang.Number number, java.lang.Class<?> type)`
`protected static java.lang.Number`	`coerceToNumber(java.lang.String val, java.lang.Class<?> type)`
`static java.lang.String`	`coerceToString(ELContext ctx, java.lang.Object obj)` Coerce an object to a string.
`static java.lang.Object`	`coerceToType(ELContext ctx, java.lang.Object obj, java.lang.Class<?> type)`
`static int`	`compare(ELContext ctx, java.lang.Object obj0, java.lang.Object obj1)` Compare two objects, after coercing to the same type if appropriate.
`static boolean`	`equals(ELContext ctx, java.lang.Object obj0, java.lang.Object obj1)` Compare two objects for equality, after coercing to the same type if appropriate.
`static boolean`	`isBigDecimalOp(java.lang.Object obj0, java.lang.Object obj1)`
`static boolean`	`isBigIntegerOp(java.lang.Object obj0, java.lang.Object obj1)`
`static boolean`	`isDoubleOp(java.lang.Object obj0, java.lang.Object obj1)`
`static boolean`	`isLongOp(java.lang.Object obj0, java.lang.Object obj1)`
`static boolean`	`isStringFloat(java.lang.String str)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - COERCE_TO_ZERO
```
protected static final boolean COERCE_TO_ZERO
```
- Constructor Detail
  - ELSupport
```
public ELSupport()
```
- Method Detail
  - compare
```
public static final int compare(ELContext ctx,
          java.lang.Object obj0,
          java.lang.Object obj1)
                         throws ELException
```
    Compare two objects, after coercing to the same type if appropriate. If the objects are identical, or they are equal according to equals(ELContext, Object, Object) then return 0. If either object is a BigDecimal, then coerce both to BigDecimal first. Similarly for Double(Float), BigInteger, and Long(Integer, Char, Short, Byte). Otherwise, check that the first object is an instance of Comparable, and compare against the second object. If that is null, return 1, otherwise return the result of comparing against the second object. Similarly, if the second object is Comparable, if the first is null, return -1, else return the result of comparing against the first object. A null object is considered as:
    - ZERO when compared with Numbers
    - the empty string for String compares
    - Otherwise null is considered to be lower than anything else.
    Parameters:
    ctx - the context in which this comparison is taking place
    obj0 - first object
    obj1 - second object
    
    Returns:
    -1, 0, or 1 if this object is less than, equal to, or greater than val.
    
    Throws:
    
    ELException - if neither object is Comparable
    
    java.lang.ClassCastException - if the objects are not mutually comparable
  - equals
```
public static final boolean equals(ELContext ctx,
             java.lang.Object obj0,
             java.lang.Object obj1)
                            throws ELException
```
    Compare two objects for equality, after coercing to the same type if appropriate. If the objects are identical (including both null) return true. If either object is null, return false. If either object is Boolean, coerce both to Boolean and check equality. Similarly for Enum, String, BigDecimal, Double(Float), Long(Integer, Short, Byte, Character) Otherwise default to using Object.equals().
    
    Parameters:
    ctx - the context in which this equality test is taking place
    obj0 - the first object
    obj1 - the second object
    
    Returns:
    true if the objects are equal
    
    Throws:
    
    ELException - if one of the coercion fails
  - coerceToEnum
```
public static final java.lang.Enum<?> coerceToEnum(ELContext ctx,
                             java.lang.Object obj,
                             java.lang.Class type)
```
  - coerceToBoolean
```
public static final java.lang.Boolean coerceToBoolean(ELContext ctx,
                                java.lang.Object obj,
                                boolean primitive)
                                               throws ELException
```
    Convert an object to Boolean. Null and empty string are false.
    
    Parameters:
    ctx - the context in which this conversion is taking place
    obj - the object to convert
    primitive - is the target a primitive in which case coercion to null is not permitted
    
    Returns:
    the Boolean value of the object
    
    Throws:
    
    ELException - if object is not Boolean or String
  - coerceToNumber
```
protected static final java.lang.Number coerceToNumber(java.lang.Number number,
                              java.lang.Class<?> type)
                                                throws ELException
```
    Throws:
    
    ELException
  - coerceToNumber
```
public static final java.lang.Number coerceToNumber(ELContext ctx,
                              java.lang.Object obj,
                              java.lang.Class<?> type)
                                             throws ELException
```
    Throws:
    
    ELException
  - coerceToNumber
```
protected static final java.lang.Number coerceToNumber(java.lang.String val,
                              java.lang.Class<?> type)
                                                throws ELException
```
    Throws:
    
    ELException
  - coerceToString
```
public static final java.lang.String coerceToString(ELContext ctx,
                              java.lang.Object obj)
```
    Coerce an object to a string.
    
    Parameters:
    ctx - the context in which this conversion is taking place
    obj - the object to convert
    
    Returns:
    the String value of the object
  - coerceToType
```
public static final java.lang.Object coerceToType(ELContext ctx,
                            java.lang.Object obj,
                            java.lang.Class<?> type)
                                           throws ELException
```
    Throws:
    
    ELException
  - isBigDecimalOp
```
public static final boolean isBigDecimalOp(java.lang.Object obj0,
                     java.lang.Object obj1)
```
  - isBigIntegerOp
```
public static final boolean isBigIntegerOp(java.lang.Object obj0,
                     java.lang.Object obj1)
```
  - isDoubleOp
```
public static final boolean isDoubleOp(java.lang.Object obj0,
                 java.lang.Object obj1)
```
  - isLongOp
```
public static final boolean isLongOp(java.lang.Object obj0,
               java.lang.Object obj1)
```
  - isStringFloat
```
public static final boolean isStringFloat(java.lang.String str)
```

Class ELSupport

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

COERCE_TO_ZERO

Constructor Detail

ELSupport

Method Detail

compare

equals

coerceToEnum

coerceToBoolean

coerceToNumber

coerceToNumber

coerceToNumber

coerceToString

coerceToType

isBigDecimalOp

isBigIntegerOp

isDoubleOp

isLongOp

isStringFloat