Package org.springframework.data.repository.query

Class ValueExpressionQueryRewriter

java.lang.Object

org.springframework.data.repository.query.ValueExpressionQueryRewriter

Direct Known Subclasses:

ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter

public class ValueExpressionQueryRewriter
extends Object

A ValueExpressionQueryRewriter is able to detect Value expressions in a query string and to replace them with bind variables.

Result of the parse process is a ValueExpressionQueryRewriter.ParsedQuery which provides the transformed query string. Alternatively and preferred one may provide a QueryMethodValueEvaluationContextAccessor via withEvaluationContextAccessor(QueryMethodValueEvaluationContextAccessor) which will yield the more powerful ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter.

Typical usage looks like

 ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter rewriter = ValueExpressionQueryRewriter
                .of(valueExpressionParser, (counter, expression) -> String.format("__$synthetic$__%d", counter), String::concat)
                .withEvaluationContextAccessor(evaluationContextProviderFactory);

 ValueExpressionQueryRewriter.QueryExpressionEvaluator evaluator = rewriter.parse(query, queryMethod.getParameters());

 evaluator.evaluate(objects).forEach(parameterMap::addValue);
 

Since:

3.3

Author:

Jens Schauder, Gerrit Meier, Mark Paluch

See Also:

• ValueExpression

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter	An extension of ValueExpressionQueryRewriter that can create ValueExpressionQueryRewriter.QueryExpressionEvaluator instances as it also knows about a QueryMethodValueEvaluationContextAccessor.
class	ValueExpressionQueryRewriter.ParsedQuery	Parses a query string, identifies the contained Value expressions, replaces them with bind parameters and offers a Map from those bind parameters to the value expression.
class	ValueExpressionQueryRewriter.QueryExpressionEvaluator	Evaluates Value expressions as detected by ValueExpressionQueryRewriter.ParsedQuery based on parameter information from a method and parameter values from a method call.

Method Summary

Modifier and Type	Method	Description
static ValueExpressionQueryRewriter	of(ValueExpressionParser expressionParser, BiFunction<Integer,String,String> parameterNameSource, BiFunction<String,String,String> replacementSource)	Creates a new ValueExpressionQueryRewriter using the given ValueExpressionParser and rewrite functions.
static ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter	of(ValueExpressionDelegate delegate, BiFunction<Integer,String,String> parameterNameSource, BiFunction<String,String,String> replacementSource)	Creates a new EvaluatingValueExpressionQueryRewriter using the given ValueExpressionDelegate and rewrite functions.
ValueExpressionQueryRewriter.ParsedQuery	parse(String query)	Parses the query for value expressions using the pattern:
ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter	withEvaluationContextAccessor(QueryMethodValueEvaluationContextAccessor accessor)	Creates a ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter from the current one and the given QueryMethodValueEvaluationContextAccessor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

of

public static ValueExpressionQueryRewriter of(ValueExpressionParser expressionParser,
 BiFunction<Integer,String,String> parameterNameSource,
 BiFunction<String,String,String> replacementSource)

Creates a new ValueExpressionQueryRewriter using the given ValueExpressionParser and rewrite functions.

Parameters:

expressionParser - the expression parser to use.

parameterNameSource - function to generate parameter names. Typically, a function of the form (index, expression) -> "__some_placeholder_" + index.

replacementSource - function to generate replacements. Typically, a concatenation of the prefix and the parameter name such as String::concat.

Returns:

a ValueExpressionQueryRewriter instance to rewrite queries and extract parsed ValueExpressions.

of

public static ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter of(ValueExpressionDelegate delegate,
 BiFunction<Integer,String,String> parameterNameSource,
 BiFunction<String,String,String> replacementSource)

Creates a new EvaluatingValueExpressionQueryRewriter using the given ValueExpressionDelegate and rewrite functions.

Parameters:

delegate - the ValueExpressionDelegate to use for parsing and to obtain EvaluationContextAccessor from.

parameterNameSource - function to generate parameter names. Typically, a function of the form (index, expression) -> "__some_placeholder_" + index.

replacementSource - function to generate replacements. Typically, a concatenation of the prefix and the parameter name such as String::concat.

Returns:

a EvaluatingValueExpressionQueryRewriter instance to rewrite queries and extract parsed ValueExpressions.

Since:

3.4

parse

public ValueExpressionQueryRewriter.ParsedQuery parse(String query)

Parses the query for value expressions using the pattern:

 <prefix>#{<spel>}
 <prefix>${<property placeholder>}
 

with prefix being the character ':' or '?'. Parsing honors quoted Strings enclosed in single or double quotation marks.

Parameters:

query - a query containing Value Expressions in the format described above. Must not be null.

Returns:

A ValueExpressionQueryRewriter.ParsedQuery which makes the query with Value Expressions replaced by bind parameters and a map from bind parameter to Value Expression available. Guaranteed to be not null.

withEvaluationContextAccessor

public ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter withEvaluationContextAccessor(QueryMethodValueEvaluationContextAccessor accessor)

Creates a ValueExpressionQueryRewriter.EvaluatingValueExpressionQueryRewriter from the current one and the given QueryMethodValueEvaluationContextAccessor.

Parameters:

accessor - must not be null.

Returns:

EvaluatingValueExpressionQueryRewriter instance to rewrite and evaluate Value Expressions.