/*
* Copyright 2017 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.integration.file.filters;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.integration.expression.ExpressionUtils;
import org.springframework.util.Assert;
/**
* A SpEL expression based {@link AbstractFileListFilter} implementation.
*
* @author Artem Bilan
*
* @since 5.0
*/
public class ExpressionFileListFilter<F> extends AbstractFileListFilter<F>
implements BeanFactoryAware {
private static final ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();
private final Expression expression;
private BeanFactory beanFactory;
private EvaluationContext evaluationContext;
public ExpressionFileListFilter(String expression) {
this(EXPRESSION_PARSER.parseExpression(expression));
Assert.hasText(expression, "'expression' must not be empty");
}
public ExpressionFileListFilter(Expression expression) {
Assert.notNull(expression, "'expression' must not be null");
this.expression = expression;
}
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
this.beanFactory = beanFactory;
}
@Override
public boolean accept(F file) {
return this.expression.getValue(getEvaluationContext(), file, Boolean.class);
}
private EvaluationContext getEvaluationContext() {
if (this.evaluationContext == null) {
this.evaluationContext = ExpressionUtils.createStandardEvaluationContext(this.beanFactory);
}
return this.evaluationContext;
}
}