/*
* Copyright 2018-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.repository.query;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.Collectors;
import org.springframework.data.repository.query.SpelQueryContext.SpelExtractor;
import org.springframework.data.spel.ExpressionDependencies;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
Evaluates SpEL expressions as extracted by the SpelExtractor
based on parameter information from a method and parameter values from a method call. Author: Jens Schauder, Gerrit Meier, Oliver Gierke See Also: Since: 2.1
/**
* Evaluates SpEL expressions as extracted by the {@link SpelExtractor} based on parameter information from a method and
* parameter values from a method call.
*
* @author Jens Schauder
* @author Gerrit Meier
* @author Oliver Gierke
* @since 2.1
* @see SpelQueryContext#parse(String, Parameters)
*/
public class SpelEvaluator {
private final static SpelExpressionParser PARSER = new SpelExpressionParser();
private final QueryMethodEvaluationContextProvider evaluationContextProvider;
private final Parameters<?, ?> parameters;
private final SpelExtractor extractor;
public SpelEvaluator(QueryMethodEvaluationContextProvider evaluationContextProvider, Parameters<?, ?> parameters,
SpelExtractor extractor) {
this.evaluationContextProvider = evaluationContextProvider;
this.parameters = parameters;
this.extractor = extractor;
}
Evaluate all the SpEL expressions in parameterNameToSpelMap
based on values provided as an argument. Params: - values – Parameter values. Must not be null.
Returns: a map from parameter name to evaluated value. Guaranteed to be not null.
/**
* Evaluate all the SpEL expressions in {@link #parameterNameToSpelMap} based on values provided as an argument.
*
* @param values Parameter values. Must not be {@literal null}.
* @return a map from parameter name to evaluated value. Guaranteed to be not {@literal null}.
*/
public Map<String, Object> evaluate(Object[] values) {
Assert.notNull(values, "Values must not be null.");
return extractor.getParameters().collect(Collectors.toMap(//
Entry::getKey, //
it -> getSpElValue(it.getValue(), values) //
));
}
Returns the query string produced by the intermediate SpEL expression collection step.
Returns:
/**
* Returns the query string produced by the intermediate SpEL expression collection step.
*
* @return
*/
public String getQueryString() {
return extractor.getQueryString();
}
@Nullable
private Object getSpElValue(String expressionString, Object[] values) {
Expression expression = PARSER.parseExpression(expressionString);
EvaluationContext evaluationContext = evaluationContextProvider.getEvaluationContext(parameters, values,
ExpressionDependencies.discover(expression));
return expression.getValue(evaluationContext);
}
}