org.bitbucket.gt_tech.spring.data.querydsl.value.operators

Interface ExpressionProvider<P extends com.querydsl.core.types.Path,V>

Type Parameters:

P - type of Path, example - StringPath or EnumPath.

V - type of value for path. Depending on type of path, this could be a collection of String or else Collection of String or String or Enum or Collection of Enum. This must not be wrapped in Optional.

public interface ExpressionProvider<P extends com.querydsl.core.types.Path,V>

Interface establishes contract for providing Predicate or BooleanExpression to be used to pass to QueryDSL for querying underlying store.

This interface and entire component of QueryDSL extension is to build on top of Spring data QueryDSL extensions for QueryDSL by providing further low level of search operators within values which is a powerful extension by empowering client application to perform variety searches, an improvement over largely static capability out of the box to statically define different binding using QuerydslBinderCustomizer.

With this extension, client's can request in a variety of forms like below:

• Search all resources which has either any email in 'company.com' domain or else have a specific email specified by second parameter /api/user/search?emails.value=endsWith(@company.com)&emails.value=johndoe@somemail.com
• Search for a user having any *admin* role - /api/user/search?role=contains(admin)
• Search for any user having not having email in some specific domain - /api/user/search?emails .value=not(contains(@company.com))
• Search any user not having a specific attribute - job_level as "executive" /api/user/search?profile.job_level=ne(executive)

Interface also defines supported operators though specific implementation may only support a subset of them so must be checked on implementation on supported Operators to avoid unpredictable errors in search logic/processing. Implementation must support all Logical Operators.

Author:

gt_tech

See Also:

Operator, Spring data Querydsl Extensions, QuerydslBinderCustomizer

Field Summary

Fields

Modifier and Type	Field and Description
static String	OPERATOR_VALUE_DELIMITER_PREFIX Provides a operator value delimiter prefix for when explicit delimiter is provided.
static String	OPERATOR_VALUE_DELIMITER_SUFFIX Provides a operator value delimiter suffix for when explicit delimiter is provided.

Method Summary

Modifier and Type	Method and Description
default Optional<com.querydsl.core.types.dsl.BooleanExpression>	getExpression(P path, V value) Method establishes the contract to retrieve a BooleanExpression based on implementation specific logic's processing of supplied value(s).
default Optional<com.querydsl.core.types.Predicate>	getPredicate(P path, V value) Method establishes contract to retrieve a predicate based on implementation specific logic's processing of supplied value(s).
static <S extends String> Optional<Operator>	isOperator(Operator[] operators, S value) Utility function to check if provided value starts with an Operator.
static boolean	isOperator(Operator operator, String value) Returns true if provided value is wrapped in supplied operator
static <S extends String> Optional<Operator>	isOperator(S value) Utility function to check if provided value starts with an Operator.
static void	validateComposition(String value) Utility method which validates proper ordering and opening/closing delimiters of operators on supplied value

Field Detail

OPERATOR_VALUE_DELIMITER_PREFIX

static final String OPERATOR_VALUE_DELIMITER_PREFIX

Provides a operator value delimiter prefix for when explicit delimiter is provided. for e.g. operator(value)

See Also:

Constant Field Values

OPERATOR_VALUE_DELIMITER_SUFFIX

static final String OPERATOR_VALUE_DELIMITER_SUFFIX

Provides a operator value delimiter suffix for when explicit delimiter is provided. for e.g. operator(value)

See Also:

Constant Field Values

Method Detail

getPredicate

default Optional<com.querydsl.core.types.Predicate> getPredicate(P path,
                                                                 V value)

Method establishes contract to retrieve a predicate based on implementation specific logic's processing of supplied value(s).

Default implementation delegates to getExpression(Path, Object)

Parameters:

path - Q Path Path for which expression is to be formed using supplied value

value - Input value value(s) to be used to form expression, this can be a primitive or a collection of values but must not be wrapped in Optional

Returns:

Optional of Predicate based on provided value.

getExpression

default Optional<com.querydsl.core.types.dsl.BooleanExpression> getExpression(P path,
                                                                              V value)

Method establishes the contract to retrieve a BooleanExpression based on implementation specific logic's processing of supplied value(s).

Default implementation returns an empty Optional.

Parameters:

path - Q Path Path for which expression is to be formed using supplied value

value - Input value value(s) to be used to form expression, this can be a primitive or a collection of values but must not be wrapped in Optional

Returns:

Optional of BooleanExpression based on provided value.

Throws:

UnsupportedOperationException - if an operator is used in unsupported order or on unsupported digits (for example, startWith operator being used on String values)

isOperator

static <S extends String> Optional<Operator> isOperator(S value)

Utility function to check if provided value starts with an Operator. Compares against all available Operators.

Parameters:

value - input string to check for Operator

Returns:

Operator if supplied String starts with an operator, empty Optional otherwise

Throws:

UnsupportedOperationException - if an operator is used in unsupported order or on unsupported digits (for example, startWith operator being used on String values)

isOperator

static <S extends String> Optional<Operator> isOperator(Operator[] operators,
                                                        S value)

Utility function to check if provided value starts with an Operator. Compares against provided operators.

Parameters:

value - input string to check for Operator

operators - List of operators to check against

Returns:

Operator if supplied String starts with an operator, empty Optional otherwise

Throws:

UnsupportedOperationException - if an operator is used in unsupported order or on unsupported digits (for example, startWith operator being used on String values)

isOperator

static boolean isOperator(Operator operator,
                          String value)

Returns true if provided value is wrapped in supplied operator

Parameters:

operator - Operator to check for on provided value

value - value to check against if it's wrapped in provided operator

Returns:

true if provided value is wrapped in supplied operator, false otherwise

validateComposition

static void validateComposition(String value)

Utility method which validates proper ordering and opening/closing delimiters of operators on supplied value

Parameters:

value - value to check for proper composition

Throws:

IllegalArgumentException - if an invalid composition is found in provided value