org.springframework.integration.util.FixedMethodFilter.java Source code

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Here is the source code for org.springframework.integration.util.FixedMethodFilter.java

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/*
 * Copyright 2002-2019 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.integration.util;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.springframework.expression.MethodFilter;
import org.springframework.util.Assert;

/**
 * A {@link MethodFilter} implementation that will always return
 * the same Method instance within a single-element list if it is
 * present in the candidate list. If the Method is not present
 * in the candidate list, it will return an empty list.
 *
 * @author Mark Fisher
 * @author Gary Russell
 * @since 2.0
 */
public class FixedMethodFilter implements MethodFilter {

    private final Method method;

    public FixedMethodFilter(Method method) {
        Assert.notNull(method, "method must not be null");
        this.method = method;
    }

    public List<Method> filter(List<Method> methods) {
        if (methods != null && methods.contains(this.method)) {
            List<Method> filteredList = new ArrayList<Method>(1);
            filteredList.add(this.method);
            return filteredList;
        }
        return Collections.<Method>emptyList();
    }

}