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Spring Data module for JPA repositories.
/*
* Copyright 2014 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
*
* http://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.jpa.repository.query;
import java.util.List;
import javax.persistence.Query;
import org.springframework.data.jpa.repository.query.JpaParameters.JpaParameter;
import org.springframework.data.jpa.repository.query.StringQuery.ParameterBinding;
import org.springframework.data.repository.query.EvaluationContextProvider;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.Assert;
/**
* A {@link StringQueryParameterBinder} that is able to bind synthetic query parameters.
*
* @author Thomas Darimont
*/
class SpelExpressionStringQueryParameterBinder extends StringQueryParameterBinder {
private final StringQuery query;
private final EvaluationContextProvider evaluationContextProvider;
private final SpelExpressionParser parser;
/**
* Creates a new {@link SpelExpressionStringQueryParameterBinder}.
*
* @param parameters must not be {@literal null}
* @param values must not be {@literal null}
* @param query must not be {@literal null}
* @param evaluationContextProvider must not be {@literal null}
* @param parser must not be {@literal null}
*/
public SpelExpressionStringQueryParameterBinder(JpaParameters parameters, Object[] values, StringQuery query,
EvaluationContextProvider evaluationContextProvider, SpelExpressionParser parser) {
super(parameters, values, query);
Assert.notNull(evaluationContextProvider, "EvaluationContextProvider must not be null!");
Assert.notNull(parser, "SpelExpressionParser must not be null!");
this.evaluationContextProvider = evaluationContextProvider;
this.query = query;
this.parser = parser;
}
/*
* (non-Javadoc)
* @see org.springframework.data.jpa.repository.query.ParameterBinder#bind(javax.persistence.Query)
*/
@Override
public T bind(T jpaQuery) {
return potentiallyBindExpressionParameters(super.bind(jpaQuery));
}
/**
* @param jpaQuery must not be {@literal null}
* @return
*/
private T potentiallyBindExpressionParameters(T jpaQuery) {
if (isJpaParameterInformationReliable(jpaQuery) && jpaQuery.getParameters().isEmpty()) {
// We can rely on the fact there are no parameters in the given query.
return jpaQuery;
}
for (ParameterBinding binding : query.getParameterBindings()) {
if (binding.isExpression()) {
Expression expr = parseExpressionString(binding.getExpression());
Object value = evaluateExpression(expr);
try {
if (binding.getName() != null) {
jpaQuery.setParameter(binding.getName(), binding.prepare(value));
} else {
jpaQuery.setParameter(binding.getPosition(), binding.prepare(value));
}
} catch (IllegalArgumentException iae) {
// Since Eclipse doesn't reliably report whether a query has parameters
// we simply try to set the parameters and ignore possible failures.
}
}
}
return jpaQuery;
}
private boolean isJpaParameterInformationReliable(T jpaQuery) {
String className = jpaQuery.getClass().getName();
return className.startsWith("org.apache.openjpa") || className.startsWith("org.hibernate");
}
/**
* Parses the given {@code expressionString} into a SpEL {@link Expression}.
*
* @param expressionString
* @return
*/
private Expression parseExpressionString(String expressionString) {
return parser.parseExpression(expressionString);
}
/**
* Evaluates the given SpEL {@link Expression}.
*
* @param expr
* @return
*/
private Object evaluateExpression(Expression expr) {
return expr.getValue(getEvaluationContext(), Object.class);
}
/**
* Returns the {@link StandardEvaluationContext} to use for evaluation.
*
* @return
*/
private EvaluationContext getEvaluationContext() {
return evaluationContextProvider.getEvaluationContext(getParameters(), getValues());
}
/*
* (non-Javadoc)
* @see org.springframework.data.jpa.repository.query.ParameterBinder#canBindParameter(org.springframework.data.jpa.repository.query.JpaParameters.JpaParameter)
*/
@Override
protected boolean canBindParameter(JpaParameter parameter) {
List parameterBindings = query.getParameterBindings();
// if no parameter bindings are present, we simply rely on the check in super.
if (parameterBindings.isEmpty()) {
return super.canBindParameter(parameter);
}
// otherwise determine whether there are any non expression parameters left to be bound.
int expressionParameterCount = 0;
for (ParameterBinding binding : parameterBindings) {
if (binding.isExpression()) {
expressionParameterCount++;
}
}
boolean allParametersAreUsedInExpressions = parameterBindings.size() - expressionParameterCount == 0;
// if all parameters are used in expressions, then we can skip their bindings now, since they'll get bound later.
return !allParametersAreUsedInExpressions && super.canBindParameter(parameter);
}
}