java.lang.Object
- com.zfabrik.util.expression.X

Direct Known Subclasses:

X.BinaryOp, X.UnaryOp, X.Val, X.Var
```
public abstract class X
extends java.lang.Object
```
Simple boolean expression language as a Java expressed DSL. X is used in component repositories to formulate component queries but may be used anywhere where simple boolean expressions are useful.
A built-in evaluation of an expression over a map defining a context is supported.
For example, given a map m={"a":5, "b":"hello"},
```
 var("a").ge(val(6)).and(var("b").eq(val("hello"))).eval(m) 
 
```
would evaluate to false while
```
 var("a").le(val(6)).and(var("b").eq(val("hello"))).eval(m) 
 
```
would evaluate to true.
Author:

hb

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`X.And`	"AND" logical operator
`static class`	`X.BinaryOp`	Abstract binary operators
`static class`	`X.Eq`	"equality" comparison operator.
`static class`	`X.Ge`	"greater or equal" comparison operator.
`static class`	`X.Gt`	"greater than" comparison operator.
`static class`	`X.In`	"containment" operator.
`static class`	`X.Le`	"less or equal" comparison operator.
`static class`	`X.Lt`	"less than" comparison operator.
`static class`	`X.Neq`	"not equals" comparison operator.
`static class`	`X.Not`	Negation logical operator
`static class`	`X.Or`	"OR" logical operator
`static class`	`X.UnaryOp`	Abstract single-operand operator
`static class`	`X.Val`	Explicit value.
`static class`	`X.Var`	Variable of field value operator.
`static class`	`X.Xor`	"XOR" logical operator

Constructor Summary

Constructors
Constructor Description

X()

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`X`	`and(X x)`	Convenience method for chain-style notation of expressions.
`static X`	`and(X x, X y)`	Static factory method, for convenience
`X`	`eq(X x)`	Convenience method for chain-style notation of expressions.
`static X`	`eq(X x, X y)`	Static factory method, for convenience
`java.lang.Object`	`eval()`	Convenience version of `eval(Map)` that is equivalent to calling `eval(Map)` with an empty map or a null argument.
`abstract java.lang.Object`	`eval(java.util.Map<java.lang.String,java.lang.Object> context)`	Evaluation of the expression over a map style context that defines variable values.
`java.lang.Object`	`eval(java.util.Properties context)`	Convenience version of `eval(Map)` accepting a `Properties` argument
`X`	`ge(X x)`	Convenience method for chain-style notation of expressions.
`X`	`gt(X x)`	Convenience method for chain-style notation of expressions.
`X`	`in(X x)`	Convenience method for chain-style notation of expressions.
`X`	`le(X x)`	Convenience method for chain-style notation of expressions.
`X`	`lt(X x)`	Convenience method for chain-style notation of expressions.
`X`	`neq(X x)`	Convenience method for chain-style notation of expressions.
`static X`	`neq(X x, X y)`	Static factory method, for convenience
`X`	`not()`	Convenience method for chain-style notation of expressions.
`static X`	`not(X x)`	Static factory method, for convenience
`X`	`or(X x)`	Convenience method for chain-style notation of expressions.
`static X`	`or(X x, X y)`	Static factory method, for convenience
`static X`	`val(java.lang.Object val)`	Static factory method, for convenience
`static X`	`var(java.lang.String name)`	Static factory method, for convenience
`X`	`xor(X x)`	Convenience method for chain-style notation of expressions.
`static X`	`xor(X x, X y)`	Static factory method, for convenience

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

- Constructor Detail
  - X
```
public X()
```
- Method Detail
  - or
```
public X or(X x)
```
    Convenience method for chain-style notation of expressions.
  - and
```
public X and(X x)
```
    Convenience method for chain-style notation of expressions.
  - xor
```
public X xor(X x)
```
    Convenience method for chain-style notation of expressions.
  - eq
```
public X eq(X x)
```
    Convenience method for chain-style notation of expressions.
  - lt
```
public X lt(X x)
```
    Convenience method for chain-style notation of expressions.
  - le
```
public X le(X x)
```
    Convenience method for chain-style notation of expressions.
  - gt
```
public X gt(X x)
```
    Convenience method for chain-style notation of expressions.
  - ge
```
public X ge(X x)
```
    Convenience method for chain-style notation of expressions.
  - in
```
public X in(X x)
```
    Convenience method for chain-style notation of expressions.
  - neq
```
public X neq(X x)
```
    Convenience method for chain-style notation of expressions.
  - not
```
public X not()
```
    Convenience method for chain-style notation of expressions.
  - or
```
public static X or(X x,
                   X y)
```
    Static factory method, for convenience
  - and
```
public static X and(X x,
                    X y)
```
    Static factory method, for convenience
  - xor
```
public static X xor(X x,
                    X y)
```
    Static factory method, for convenience
  - eq
```
public static X eq(X x,
                   X y)
```
    Static factory method, for convenience
  - neq
```
public static X neq(X x,
                    X y)
```
    Static factory method, for convenience
  - not
```
public static X not(X x)
```
    Static factory method, for convenience
  - val
```
public static X val(java.lang.Object val)
```
    Static factory method, for convenience
  - var
```
public static X var(java.lang.String name)
```
    Static factory method, for convenience
  - eval
```
public abstract java.lang.Object eval(java.util.Map<java.lang.String,java.lang.Object> context)
```
    Evaluation of the expression over a map style context that defines variable values.
  - eval
```
public java.lang.Object eval(java.util.Properties context)
```
    Convenience version of eval(Map) accepting a Properties argument
  - eval
```
public java.lang.Object eval()
```
    Convenience version of eval(Map) that is equivalent to calling eval(Map) with an empty map or a null argument.

Class X

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

X

Method Detail

or

and

xor

eq

lt

le

gt

ge

in

neq

not

or

and

xor

eq

neq

not

val

var

eval

eval

eval