org.springframework.cache.interceptor.DefaultKeyGenerator Maven / Gradle / Ivy
/*
* Copyright 2002-2011 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.cache.interceptor;
import java.lang.reflect.Method;
import org.springframework.cache.interceptor.KeyGenerator;
/**
* Default key generator. Returns {@value #NO_PARAM_KEY} if no
* parameters are provided, the parameter itself if only one is given or
* a hash code computed from all given parameters' hash code values.
* Uses the constant value {@value #NULL_PARAM_KEY} for any
* {@code null} parameters given.
*
* @author Costin Leau
* @author Chris Beams
* @since 3.1
*/
public class DefaultKeyGenerator implements KeyGenerator {
public static final int NO_PARAM_KEY = 0;
public static final int NULL_PARAM_KEY = 53;
public Object generate(Object target, Method method, Object... params) {
if (params.length == 1) {
return (params[0] == null ? NULL_PARAM_KEY : params[0]);
}
if (params.length == 0) {
return NO_PARAM_KEY;
}
int hashCode = 17;
for (Object object : params) {
hashCode = 31 * hashCode + (object == null ? NULL_PARAM_KEY : object.hashCode());
}
return Integer.valueOf(hashCode);
}
}