Interface IExpressionFactory
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public interface IExpressionFactoryThis interface provides all the factory methods needed to create the nodes of the expression tree.- Since:
- 2.0
- Restriction:
- This interface is not intended to be implemented directly by clients.
- Restriction:
- This interface is not intended to be extended directly by clients.
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Field Summary
Fields Modifier and Type Field Description static StringFUNC_BOOLEANstatic StringFUNC_CLASSstatic StringFUNC_FILTERstatic StringFUNC_RANGEstatic StringFUNC_VERSIONstatic IExpression[]NO_ARGS
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description IExpressionall(IExpression collection, IExpression lambda)Create a collection filter that yields true if thelambdayields true for all of the elements of thecollectionIExpressionand(IExpression... operands)Create a logical and of itsoperands.IExpressionarray(IExpression... elements)Create an array of elements.IExpressionassignment(IExpression variable, IExpression expression)Creates an expression that represents a variable assignmentIExpressionat(IExpression target, IExpression key)Create an lookup ofkeyin thetarget.IExpressioncollect(IExpression collection, IExpression lambda)Create an expression that collects the result of evaluating each element in a new collection.IExpressioncondition(IExpression test, IExpression ifTrue, IExpression ifFalse)Create an expression that first evaluates atestand then, depending on the outcome, evaluates eitherifTrueorifFalse.IExpressionconstant(Object value)Creates an expression that evaluates to the constantvalue.<T> IContextExpression<T>contextExpression(IExpression expr, Object... parameters)Creates a top level expression that represents a full query.IEvaluationContextcreateContext(Object... params)Create an evaluation context with one single variableIEvaluationContextcreateContext(IExpression[] variables, Object... params)Create an evaluation context with one single variableIExpressionequals(IExpression lhs, IExpression rhs)Create an expression that tests iflhsis equal torhs.IExpressionexists(IExpression collection, IExpression lambda)Create a collection filter that yields true if thelambdayields true for at least one of the elements of thecollectionIFilterExpressionfilterExpression(IExpression expression)Creates a top level expression suitable for predicate matchingIExpressionfirst(IExpression collection, IExpression lambda)Create an expression that yields the first element of thecollectionfor which thelambdayieldstrue.IExpressionflatten(IExpression collection)Intended to be applied on collections of collections.IExpressionfunction(Object function, IExpression... args)Given one of the values in the map returned bygetFunctionMap(), this method returns a function expression.Map<String,? extends Object>getFunctionMap()Returns a map of functions supported by this factory.IExpressiongreater(IExpression lhs, IExpression rhs)Create an expression that tests iflhsis greater thanrhs.IExpressiongreaterEqual(IExpression lhs, IExpression rhs)Create an expression that tests iflhsis greater than or equal torhs.IExpressionindexedParameter(int index)Creates an indexed parameter expressionIExpressionintersect(IExpression c1, IExpression c2)Create an intersection ofc1andc2IExpressionlambda(IExpression variable, IExpression body)Creates a lambda expression that takes exactly one variable.IExpressionlambda(IExpression variable, IExpression[] initialAssignments, IExpression body)Creates a lambda expression that takes more then one variable (currying).IExpressionlatest(IExpression collection)Create an expression that yields a new collection consisting of the latest version of the elements of thecollection.IExpressionless(IExpression lhs, IExpression rhs)Create an expression that tests iflhsis less thanrhs.IExpressionlessEqual(IExpression lhs, IExpression rhs)Create an expression that tests iflhsis less than or equal torhs.IExpressionlimit(IExpression collection, int count)Create an expression that yields a new collection consisting of the count first elements of the source collection.IExpressionlimit(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 bylimit.IExpressionmatches(IExpression lhs, IExpression rhs)Create an expression that tests iflhsmatchesrhs.<T> IMatchExpression<T>matchExpression(IExpression expression, Object... parameters)Creates a parameterized top level expression suitable for predicate matchingIExpressionmember(IExpression target, String name)Creates a member accessor expression.IExpressionmemberCall(IExpression target, String name, IExpression... args)Creates a member call expression.IExpressionnormalize(List<? extends IExpression> operands, int expressionType)Performs boolean normalization on the expression to create a canonical form.IExpressionnot(IExpression operand)Creates an expression that negates the result of evaluating itsoperand.IExpressionor(IExpression... operands)Create a logical or of itsoperands.IExpressionpipe(IExpression... expressions)Create a pipe of expressions.IExpressionselect(IExpression collection, IExpression lambda)Create an expression that yields a new collection consisting of all elements of thecollectionfor which thelambdayieldstrue.IExpressionthisVariable()Returns the variable that representsthisin an expressionIExpressiontoExpression(IQuery<?> query)Wrap anIQueryas an expression.IExpressiontraverse(IExpression collection, IExpression lambda)Recursively traverse and collect elements based on a conditionIExpressionunion(IExpression c1, IExpression c2)Create a union ofc1andc2IExpressionunique(IExpression collection, IExpression cache)Create an expression that yields a new collection where each element is unique.IExpressionvariable(String name)Creates an expression that represents a variable
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Field Detail
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FUNC_BOOLEAN
static final String FUNC_BOOLEAN
- See Also:
- Constant Field Values
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FUNC_VERSION
static final String FUNC_VERSION
- See Also:
- Constant Field Values
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FUNC_CLASS
static final String FUNC_CLASS
- See Also:
- Constant Field Values
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FUNC_RANGE
static final String FUNC_RANGE
- See Also:
- Constant Field Values
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FUNC_FILTER
static final String FUNC_FILTER
- See Also:
- Constant Field Values
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NO_ARGS
static final IExpression[] NO_ARGS
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Method Detail
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all
IExpression all(IExpression collection, IExpression lambda)
Create a collection filter that yields true if thelambdayields true for all of the elements of thecollection- Parameters:
collection- The collection providing the elements to testlambda- The lambda that performs the test- Returns:
- A boolean expression
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and
IExpression and(IExpression... operands)
Create a logical and of itsoperands.- Parameters:
operands- The boolean operands- Returns:
- A boolean expression
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assignment
IExpression assignment(IExpression variable, IExpression expression)
Creates an expression that represents a variable assignment- Parameters:
variable- The variableexpression- The expression that yields the value to assign to the variable- Returns:
- An assignment expression
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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 evaluatelambda- The lambda that creates each new element- Returns:
- A collection expression
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condition
IExpression condition(IExpression test, IExpression ifTrue, IExpression ifFalse)
Create an expression that first evaluates atestand then, depending on the outcome, evaluates eitherifTrueorifFalse. The expression yields the result of theifTrueorifFalseevaluation.- Parameters:
test- The testifTrue- The code to evaluate when the test evaluates totrueifFalse- The code to evaluate when the test evaluates tofalse- Returns:
- The conditional expression
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first
IExpression first(IExpression collection, IExpression lambda)
Create an expression that yields the first element of thecollectionfor which thelambdayieldstrue.- Parameters:
collection- The collection providing the elements to testlambda- The lambda that performs the test- Returns:
- An element expression
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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
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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 usesbody- The body of the lambdainitialAssignments- Assignments to evaluate once before calling the body for each element.- Returns:
- A lambda expression with currying
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memberCall
IExpression memberCall(IExpression target, String name, IExpression... args)
Creates a member call expression.- Parameters:
target- The target for the member callname- The name of the memberargs- The arguments to use for the call- Returns:
- A member expression
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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 testlambda- The lambda that collects the children for the next iteration- Returns:
- A collection expression
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unique
IExpression unique(IExpression collection, IExpression cache)
Create an expression that yields a new collection where each element is unique. An optionalcachecan be provided if the uniqueness should span a larger scope then just the source collection.- Parameters:
collection- The source collectioncache- Optional cache to use when uniqueness should span over several invocations- Returns:
- A collection expression
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array
IExpression array(IExpression... elements)
Create an array of elements.- Parameters:
elements- The elements of the array- Returns:
- An array expression
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at
IExpression at(IExpression target, IExpression key)
Create an lookup ofkeyin thetarget. The key expression should evaluate to a string or an integer.- Parameters:
target- The target for the lookupkey- The key to use for the lookup- Returns:
- A lookup expression
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createContext
IEvaluationContext createContext(Object... params)
Create an evaluation context with one single variable- Parameters:
params- Indexed parameters to use in the expression- Returns:
- the context
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createContext
IEvaluationContext createContext(IExpression[] variables, Object... params)
Create an evaluation context with one single variable- Parameters:
params- Indexed parameters to use in the expressionvariables- The variables that will be maintained by the context- Returns:
- the context
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constant
IExpression constant(Object value)
Creates an expression that evaluates to the constantvalue.- Parameters:
value- The constant- Returns:
- A constant expression
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contextExpression
<T> IContextExpression<T> contextExpression(IExpression expr, Object... parameters)
Creates a top level expression that represents a full query.- Parameters:
expr- The queryparameters- The parameters of the query- Returns:
- A top level query expression
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equals
IExpression equals(IExpression lhs, IExpression rhs)
Create an expression that tests iflhsis equal torhs.- Parameters:
lhs- The left hand side value.rhs- The right hand side value.- Returns:
- A boolean expression
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exists
IExpression exists(IExpression collection, IExpression lambda)
Create a collection filter that yields true if thelambdayields true for at least one of the elements of thecollection- Parameters:
collection- The collection providing the elements to testlambda- The lambda that performs the test- Returns:
- A boolean expression
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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
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function
IExpression function(Object function, IExpression... args)
Given one of the values in the map returned bygetFunctionMap(), 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
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getFunctionMap
Map<String,? extends 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 thefunction(Object, IExpression[])method.- Returns:
- A key/function map.
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greater
IExpression greater(IExpression lhs, IExpression rhs)
Create an expression that tests iflhsis greater thanrhs.- Parameters:
lhs- The left hand side value.rhs- The right hand side value.- Returns:
- A boolean expression
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greaterEqual
IExpression greaterEqual(IExpression lhs, IExpression rhs)
Create an expression that tests iflhsis greater than or equal torhs.- Parameters:
lhs- The left hand side value.rhs- The right hand side value.- Returns:
- A boolean expression
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indexedParameter
IExpression indexedParameter(int index)
Creates an indexed parameter expression- Parameters:
index- The index to use- Returns:
- a parameter expression
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intersect
IExpression intersect(IExpression c1, IExpression c2)
Create an intersection ofc1andc2- Parameters:
c1- first collectionc2- second collection- Returns:
- An intersect expression
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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 usesbody- The body of the lambda- Returns:
- A lambda expression
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latest
IExpression latest(IExpression collection)
Create an expression that yields a new collection consisting of the latest version of the elements of thecollection. Each element incollectionmust implement theIVersionedIdinterface.- Parameters:
collection- The collection providing the versioned elements- Returns:
- A collection expression
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less
IExpression less(IExpression lhs, IExpression rhs)
Create an expression that tests iflhsis less thanrhs.- Parameters:
lhs- The left hand side value.rhs- The right hand side value.- Returns:
- A boolean expression
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lessEqual
IExpression lessEqual(IExpression lhs, IExpression rhs)
Create an expression that tests iflhsis less than or equal torhs.- Parameters:
lhs- The left hand side value.rhs- The right hand side value.- Returns:
- A boolean expression
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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 collectioncount- The element count limit- Returns:
- A collection expression
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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 bylimit.- Parameters:
collection- The source collectionlimit- The expression that evaluates to the element count limit- Returns:
- A collection expression
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normalize
IExpression normalize(List<? extends IExpression> operands, int expressionType)
Performs boolean normalization on the expression to create a canonical form.- Parameters:
operands- The operands to normalizeexpressionType- The type (must be eitherIExpression.TYPE_ANDorIExpression.TYPE_OR.- Returns:
- The normalized expression
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matches
IExpression matches(IExpression lhs, IExpression rhs)
Create an expression that tests iflhsmatchesrhs.- Parameters:
lhs- The left hand side value.rhs- The right hand side value.- Returns:
- A boolean expression
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matchExpression
<T> IMatchExpression<T> matchExpression(IExpression expression, Object... parameters)
Creates a parameterized top level expression suitable for predicate matching- Parameters:
expression- The boolean expressionparameters- The parameters to use in the call- Returns:
- A top level predicate expression
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member
IExpression member(IExpression target, String name)
Creates a member accessor expression.- Parameters:
target- The target for the member accessname- The name of the member- Returns:
- A member expression
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not
IExpression not(IExpression operand)
Creates an expression that negates the result of evaluating itsoperand.- Parameters:
operand- The boolean expression to negate- Returns:
- A boolean expression
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or
IExpression or(IExpression... operands)
Create a logical or of itsoperands.- Parameters:
operands- The boolean operands- Returns:
- A boolean expression
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pipe
IExpression pipe(IExpression... expressions)
Create a pipe of expressions.- Parameters:
expressions- The expressions that make out the pipe- Returns:
- A pipe expression
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select
IExpression select(IExpression collection, IExpression lambda)
Create an expression that yields a new collection consisting of all elements of thecollectionfor which thelambdayieldstrue.- Parameters:
collection- The collection providing the elements to testlambda- The lambda that performs the test- Returns:
- A collection expression
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thisVariable
IExpression thisVariable()
Returns the variable that representsthisin an expression- Returns:
- The
thisvariable.
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toExpression
IExpression toExpression(IQuery<?> query)
Wrap anIQueryas an expression.- Parameters:
query- The query to wrap.- Returns:
- An expression that wraps the query
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union
IExpression union(IExpression c1, IExpression c2)
Create a union ofc1andc2- Parameters:
c1- first collectionc2- second collection- Returns:
- A union expression
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variable
IExpression variable(String name)
Creates an expression that represents a variable- Parameters:
name- The name of the variable- Returns:
- A variable expression
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