IExpressionFactory

All Known Implementing Classes:

ExpressionFactory
```
public interface IExpressionFactory
```
This interface provides all the factory methods needed to create the nodes of the expression tree.

Since:

2.0

Field Summary

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`FUNC_BOOLEAN`
`static java.lang.String`	`FUNC_CLASS`
`static java.lang.String`	`FUNC_FILTER`
`static java.lang.String`	`FUNC_RANGE`
`static java.lang.String`	`FUNC_VERSION`
`static IExpression[]`	`NO_ARGS`

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`IExpression`	`all(IExpression collection, IExpression lambda)` Create a collection filter that yields true if the `lambda` yields true for all of the elements of the `collection`
`IExpression`	`and(IExpression... operands)` Create a logical and of its `operands`.
`IExpression`	`array(IExpression... elements)` Create an array of elements.
`IExpression`	`assignment(IExpression variable, IExpression expression)` Creates an expression that represents a variable assignment
`IExpression`	`at(IExpression target, IExpression key)` Create an lookup of `key` in the `target`.
`IExpression`	`collect(IExpression collection, IExpression lambda)` Create an expression that collects the result of evaluating each element in a new collection.
`IExpression`	`condition(IExpression test, IExpression ifTrue, IExpression ifFalse)` Create an expression that first evaluates a `test` and then, depending on the outcome, evaluates either `ifTrue` or `ifFalse`.
`IExpression`	`constant(java.lang.Object value)` Creates an expression that evaluates to the constant `value`.
`<T> IContextExpression<T>`	`contextExpression(IExpression expr, java.lang.Object... parameters)` Creates a top level expression that represents a full query.
`IEvaluationContext`	`createContext(IExpression[] variables, java.lang.Object... params)` Create an evaluation context with one single variable
`IEvaluationContext`	`createContext(java.lang.Object... params)` Create an evaluation context with one single variable
`IExpression`	`equals(IExpression lhs, IExpression rhs)` Create an expression that tests if `lhs` is equal to `rhs`.
`IExpression`	`exists(IExpression collection, IExpression lambda)` Create a collection filter that yields true if the `lambda` yields true for at least one of the elements of the `collection`
`IFilterExpression`	`filterExpression(IExpression expression)` Creates a top level expression suitable for predicate matching
`IExpression`	`first(IExpression collection, IExpression lambda)` Create an expression that yields the first element of the `collection` for which the `lambda` yields `true`.
`IExpression`	`flatten(IExpression collection)` Intended to be applied on collections of collections.
`IExpression`	`function(java.lang.Object function, IExpression... args)` Given one of the values in the map returned by `getFunctionMap()`, this method returns a function expression.
`java.util.Map<java.lang.String,? extends java.lang.Object>`	`getFunctionMap()` Returns a map of functions supported by this factory.
`IExpression`	`greater(IExpression lhs, IExpression rhs)` Create an expression that tests if `lhs` is greater than `rhs`.
`IExpression`	`greaterEqual(IExpression lhs, IExpression rhs)` Create an expression that tests if `lhs` is greater than or equal to `rhs`.
`IExpression`	`indexedParameter(int index)` Creates an indexed parameter expression
`IExpression`	`intersect(IExpression c1, IExpression c2)` Create an intersection of `c1` and `c2`
`IExpression`	`lambda(IExpression variable, IExpression body)` Creates a lambda expression that takes exactly one variable.
`IExpression`	`lambda(IExpression variable, IExpression[] initialAssignments, IExpression body)` Creates a lambda expression that takes more then one variable (currying).
`IExpression`	`latest(IExpression collection)` Create an expression that yields a new collection consisting of the latest version of the elements of the `collection`.
`IExpression`	`less(IExpression lhs, IExpression rhs)` Create an expression that tests if `lhs` is less than `rhs`.
`IExpression`	`lessEqual(IExpression lhs, IExpression rhs)` Create an expression that tests if `lhs` is less than or equal to `rhs`.
`IExpression`	`limit(IExpression collection, IExpression limit)` Create an expression that yields a new collection consisting of the n first elements of the source collection where n is determined by `limit`.
`IExpression`	`limit(IExpression collection, int count)` Create an expression that yields a new collection consisting of the count first elements of the source collection.
`IExpression`	`matches(IExpression lhs, IExpression rhs)` Create an expression that tests if `lhs` matches `rhs`.
`<T> IMatchExpression<T>`	`matchExpression(IExpression expression, java.lang.Object... parameters)` Creates a parameterized top level expression suitable for predicate matching
`IExpression`	`member(IExpression target, java.lang.String name)` Creates a member accessor expression.
`IExpression`	`memberCall(IExpression target, java.lang.String name, IExpression... args)` Creates a member call expression.
`IExpression`	`normalize(java.util.List<? extends IExpression> operands, int expressionType)` Performs boolean normalization on the expression to create a canonical form.
`IExpression`	`not(IExpression operand)` Creates an expression that negates the result of evaluating its `operand`.
`IExpression`	`or(IExpression... operands)` Create a logical or of its `operands`.
`IExpression`	`pipe(IExpression... expressions)` Create a pipe of expressions.
`IExpression`	`select(IExpression collection, IExpression lambda)` Create an expression that yields a new collection consisting of all elements of the `collection` for which the `lambda` yields `true`.
`IExpression`	`thisVariable()` Returns the variable that represents `this` in an expression
`IExpression`	`toExpression(IQuery<?> query)` Wrap an `IQuery` as an expression.
`IExpression`	`traverse(IExpression collection, IExpression lambda)` Recursively traverse and collect elements based on a condition A common scenario in p2 is that you want to start with a set of roots and then find all items that fulfill the root requirements.
`IExpression`	`union(IExpression c1, IExpression c2)` Create a union of `c1` and `c2`
`IExpression`	`unique(IExpression collection, IExpression cache)` Create an expression that yields a new collection where each element is unique.
`IExpression`	`variable(java.lang.String name)` Creates an expression that represents a variable

- Field Detail
  - FUNC_BOOLEAN
```
static final java.lang.String FUNC_BOOLEAN
```
    See Also:
    
    Constant Field Values
  - FUNC_VERSION
```
static final java.lang.String FUNC_VERSION
```
    See Also:
    
    Constant Field Values
  - FUNC_CLASS
```
static final java.lang.String FUNC_CLASS
```
    See Also:
    
    Constant Field Values
  - FUNC_RANGE
```
static final java.lang.String FUNC_RANGE
```
    See Also:
    
    Constant Field Values
  - FUNC_FILTER
```
static final java.lang.String FUNC_FILTER
```
    See Also:
    
    Constant Field Values
  - NO_ARGS
```
static final IExpression[] NO_ARGS
```
- Method Detail
  - all
```
IExpression all(IExpression collection,
                IExpression lambda)
```
    Create a collection filter that yields true if the lambda yields true for all of the elements of the collection
    
    Parameters:
    
    collection - The collection providing the elements to test
    
    lambda - The lambda that performs the test
    
    Returns:
    
    A boolean expression
  - and
```
IExpression and(IExpression... operands)
```
    Create a logical and of its operands.
    
    Parameters:
    
    operands - The boolean operands
    
    Returns:
    
    A boolean expression
  - assignment
```
IExpression assignment(IExpression variable,
                       IExpression expression)
```
    Creates an expression that represents a variable assignment
    
    Parameters:
    
    variable - The variable
    
    expression - The expression that yields the value to assign to the variable
    
    Returns:
    
    An assignment expression
  - collect
```
IExpression collect(IExpression collection,
                    IExpression lambda)
```
    Create an expression that collects the result of evaluating each element in a new collection.
    
    Parameters:
    
    collection - The collection providing the elements to evaluate
    
    lambda - The lambda that creates each new element
    
    Returns:
    
    A collection expression
  - condition
```
IExpression condition(IExpression test,
                      IExpression ifTrue,
                      IExpression ifFalse)
```
    Create an expression that first evaluates a test and then, depending on the outcome, evaluates either ifTrue or ifFalse. The expression yields the result of the ifTrue or ifFalse evaluation.
    
    Parameters:
    
    test - The test
    
    ifTrue - The code to evaluate when the test evaluates to true
    
    ifFalse - The code to evaluate when the test evaluates to false
    
    Returns:
    
    The conditional expression
  - first
```
IExpression first(IExpression collection,
                  IExpression lambda)
```
    Create an expression that yields the first element of the collection for which the lambda yields true.
    
    Parameters:
    
    collection - The collection providing the elements to test
    
    lambda - The lambda that performs the test
    
    Returns:
    
    An element expression
  - flatten
```
IExpression flatten(IExpression collection)
```
    Intended to be applied on collections of collections. Yields a single collection with all elements from the source collections, in the order they are evaluated.
    
    Parameters:
    
    collection - The collection providing the collections that provides all elements
    
    Returns:
    
    A collection expression
  - lambda
```
IExpression lambda(IExpression variable,
                   IExpression[] initialAssignments,
                   IExpression body)
```
    Creates a lambda expression that takes more then one variable (currying). Suitable for use in most collection expressions.
    
    Parameters:
    
    variable - The element variable that the lambda uses
    
    body - The body of the lambda
    
    initialAssignments - Assignments to evaluate once before calling the body for each element.
    
    Returns:
    
    A lambda expression with currying
  - memberCall
```
IExpression memberCall(IExpression target,
                       java.lang.String name,
                       IExpression... args)
```
    Creates a member call expression.
    
    Parameters:
    
    target - The target for the member call
    
    name - The name of the member
    
    args - The arguments to use for the call
    
    Returns:
    
    A member expression
  - traverse
```
IExpression traverse(IExpression collection,
                     IExpression lambda)
```
    Recursively traverse and collect elements based on a condition
    
    A common scenario in p2 is that you want to start with a set of roots and then find all items that fulfill the root requirements. Those items in turn introduce new requirements so you want to find them too. The process continues until no more requirements can be satisfied. This type of query can be performed using the traverse function.
    
    The function will evaluate an expression, once for each element, collect elements for which the evaluation returned true, then then re-evaluate using the collected result as source of elements. No element is evaluated twice. This continues until no more elements are found.
    
    Parameters:
    
    collection - The collection providing the elements to test
    
    lambda - The lambda that collects the children for the next iteration
    
    Returns:
    
    A collection expression
  - unique
```
IExpression unique(IExpression collection,
                   IExpression cache)
```
    Create an expression that yields a new collection where each element is unique. An optional cache can be provided if the uniqueness should span a larger scope then just the source collection.
    
    Parameters:
    
    collection - The source collection
    
    cache - Optional cache to use when uniqueness should span over several invocations
    
    Returns:
    
    A collection expression
  - array
```
IExpression array(IExpression... elements)
```
    Create an array of elements.
    
    Parameters:
    
    elements - The elements of the array
    
    Returns:
    
    An array expression
  - at
```
IExpression at(IExpression target,
               IExpression key)
```
    Create an lookup of key in the target. The key expression should evaluate to a string or an integer.
    
    Parameters:
    
    target - The target for the lookup
    
    key - The key to use for the lookup
    
    Returns:
    
    A lookup expression
  - createContext
```
IEvaluationContext createContext(java.lang.Object... params)
```
    Create an evaluation context with one single variable
    
    Parameters:
    
    params - Indexed parameters to use in the expression
    
    Returns:
    
    the context
  - createContext
```
IEvaluationContext createContext(IExpression[] variables,
                                 java.lang.Object... params)
```
    Create an evaluation context with one single variable
    
    Parameters:
    
    params - Indexed parameters to use in the expression
    
    variables - The variables that will be maintained by the context
    
    Returns:
    
    the context
  - constant
```
IExpression constant(java.lang.Object value)
```
    Creates an expression that evaluates to the constant value.
    
    Parameters:
    
    value - The constant
    
    Returns:
    
    A constant expression
  - contextExpression
```
<T> IContextExpression<T> contextExpression(IExpression expr,
                                            java.lang.Object... parameters)
```
    Creates a top level expression that represents a full query.
    
    Parameters:
    
    expr - The query
    
    parameters - The parameters of the query
    
    Returns:
    
    A top level query expression
  - equals
```
IExpression equals(IExpression lhs,
                   IExpression rhs)
```
    Create an expression that tests if lhs is equal to rhs.
    
    Parameters:
    
    lhs - The left hand side value.
    
    rhs - The right hand side value.
    
    Returns:
    
    A boolean expression
  - exists
```
IExpression exists(IExpression collection,
                   IExpression lambda)
```
    Create a collection filter that yields true if the lambda yields true for at least one of the elements of the collection
    
    Parameters:
    
    collection - The collection providing the elements to test
    
    lambda - The lambda that performs the test
    
    Returns:
    
    A boolean expression
  - filterExpression
```
IFilterExpression filterExpression(IExpression expression)
```
    Creates a top level expression suitable for predicate matching
    
    Parameters:
    
    expression - The boolean expression
    
    Returns:
    
    A top level predicate expression
  - function
```
IExpression function(java.lang.Object function,
                     IExpression... args)
```
    Given one of the values in the map returned by getFunctionMap(), this method returns a function expression.
    
    Parameters:
    
    function - The value obtained from the map.
    
    args - The arguments to evaluate and pass when evaluating the function.
    
    Returns:
    
    A function expression
  - getFunctionMap
```
java.util.Map<java.lang.String,? extends java.lang.Object> getFunctionMap()
```
    Returns a map of functions supported by this factory. The map is keyed by function names and the value is an object suitable to pass to the function(Object, IExpression[]) method.
    
    Returns:
    
    A key/function map.
  - greater
```
IExpression greater(IExpression lhs,
                    IExpression rhs)
```
    Create an expression that tests if lhs is greater than rhs.
    
    Parameters:
    
    lhs - The left hand side value.
    
    rhs - The right hand side value.
    
    Returns:
    
    A boolean expression
  - greaterEqual
```
IExpression greaterEqual(IExpression lhs,
                         IExpression rhs)
```
    Create an expression that tests if lhs is greater than or equal to rhs.
    
    Parameters:
    
    lhs - The left hand side value.
    
    rhs - The right hand side value.
    
    Returns:
    
    A boolean expression
  - indexedParameter
```
IExpression indexedParameter(int index)
```
    Creates an indexed parameter expression
    
    Parameters:
    
    index - The index to use
    
    Returns:
    
    a parameter expression
  - intersect
```
IExpression intersect(IExpression c1,
                      IExpression c2)
```
    Create an intersection of c1 and c2
    
    Parameters:
    
    c1 - first collection
    
    c2 - second collection
    
    Returns:
    
    An intersect expression
  - lambda
```
IExpression lambda(IExpression variable,
                   IExpression body)
```
    Creates a lambda expression that takes exactly one variable. Suitable for use in most collection expressions.
    
    Parameters:
    
    variable - The element variable that the lambda uses
    
    body - The body of the lambda
    
    Returns:
    
    A lambda expression
  - latest
```
IExpression latest(IExpression collection)
```
    Create an expression that yields a new collection consisting of the latest version of the elements of the collection. Each element in collection must implement the IVersionedId interface.
    
    Parameters:
    
    collection - The collection providing the versioned elements
    
    Returns:
    
    A collection expression
  - less
```
IExpression less(IExpression lhs,
                 IExpression rhs)
```
    Create an expression that tests if lhs is less than rhs.
    
    Parameters:
    
    lhs - The left hand side value.
    
    rhs - The right hand side value.
    
    Returns:
    
    A boolean expression
  - lessEqual
```
IExpression lessEqual(IExpression lhs,
                      IExpression rhs)
```
    Create an expression that tests if lhs is less than or equal to rhs.
    
    Parameters:
    
    lhs - The left hand side value.
    
    rhs - The right hand side value.
    
    Returns:
    
    A boolean expression
  - limit
```
IExpression limit(IExpression collection,
                  int count)
```
    Create an expression that yields a new collection consisting of the count first elements of the source collection.
    
    Parameters:
    
    collection - The source collection
    
    count - The element count limit
    
    Returns:
    
    A collection expression
  - limit
```
IExpression limit(IExpression collection,
                  IExpression limit)
```
    Create an expression that yields a new collection consisting of the n first elements of the source collection where n is determined by limit.
    
    Parameters:
    
    collection - The source collection
    
    limit - The expression that evaluates to the element count limit
    
    Returns:
    
    A collection expression
  - normalize
```
IExpression normalize(java.util.List<? extends IExpression> operands,
                      int expressionType)
```
    Performs boolean normalization on the expression to create a canonical form.
    
    Parameters:
    
    operands - The operands to normalize
    
    expressionType - The type (must be either IExpression.TYPE_AND or IExpression.TYPE_OR.
    
    Returns:
    
    The normalized expression
  - matches
```
IExpression matches(IExpression lhs,
                    IExpression rhs)
```
    Create an expression that tests if lhs matches rhs.
    
    Parameters:
    
    lhs - The left hand side value.
    
    rhs - The right hand side value.
    
    Returns:
    
    A boolean expression
  - matchExpression
```
<T> IMatchExpression<T> matchExpression(IExpression expression,
                                        java.lang.Object... parameters)
```
    Creates a parameterized top level expression suitable for predicate matching
    
    Parameters:
    
    expression - The boolean expression
    
    parameters - The parameters to use in the call
    
    Returns:
    
    A top level predicate expression
  - member
```
IExpression member(IExpression target,
                   java.lang.String name)
```
    Creates a member accessor expression.
    
    Parameters:
    
    target - The target for the member access
    
    name - The name of the member
    
    Returns:
    
    A member expression
  - not
```
IExpression not(IExpression operand)
```
    Creates an expression that negates the result of evaluating its operand.
    
    Parameters:
    
    operand - The boolean expression to negate
    
    Returns:
    
    A boolean expression
  - or
```
IExpression or(IExpression... operands)
```
    Create a logical or of its operands.
    
    Parameters:
    
    operands - The boolean operands
    
    Returns:
    
    A boolean expression
  - pipe
```
IExpression pipe(IExpression... expressions)
```
    Create a pipe of expressions.
    
    Parameters:
    
    expressions - The expressions that make out the pipe
    
    Returns:
    
    A pipe expression
  - select
```
IExpression select(IExpression collection,
                   IExpression lambda)
```
    Create an expression that yields a new collection consisting of all elements of the collection for which the lambda yields true.
    
    Parameters:
    
    collection - The collection providing the elements to test
    
    lambda - The lambda that performs the test
    
    Returns:
    
    A collection expression
  - thisVariable
```
IExpression thisVariable()
```
    Returns the variable that represents this in an expression
    
    Returns:
    
    The this variable.
  - toExpression
```
IExpression toExpression(IQuery<?> query)
```
    Wrap an IQuery as an expression.
    
    Parameters:
    
    query - The query to wrap.
    
    Returns:
    
    An expression that wraps the query
  - union
```
IExpression union(IExpression c1,
                  IExpression c2)
```
    Create a union of c1 and c2
    
    Parameters:
    
    c1 - first collection
    
    c2 - second collection
    
    Returns:
    
    A union expression
  - variable
```
IExpression variable(java.lang.String name)
```
    Creates an expression that represents a variable
    
    Parameters:
    
    name - The name of the variable
    
    Returns:
    
    A variable expression

Interface IExpressionFactory

Field Summary

Method Summary

Field Detail

FUNC_BOOLEAN

FUNC_VERSION

FUNC_CLASS

FUNC_RANGE

FUNC_FILTER

NO_ARGS

Method Detail

all

and

assignment

collect

condition

first

flatten

lambda

memberCall

traverse

unique

array

at

createContext

createContext

constant

contextExpression

equals

exists

filterExpression

function

getFunctionMap

greater

greaterEqual

indexedParameter

intersect

lambda

latest

less

lessEqual

limit

limit

normalize

matches

matchExpression

member

not

or

pipe

select

thisVariable

toExpression

union

variable