com.googlecode.memcachefy.hashkey.HashKeyGenerator.java Source code

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Here is the source code for com.googlecode.memcachefy.hashkey.HashKeyGenerator.java

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/*
 * Copyright 2012 neppo.com.br. All Rights Reserved.
 *
 * 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 com.googlecode.memcachefy.hashkey;

import org.apache.commons.lang.builder.HashCodeBuilder;

import java.lang.reflect.Method;

/**
 * Hash key generator
 *
 * @author bhlangonijr
 */
public class HashKeyGenerator {

    private static final int NULL_PARAM_KEY = 53;

    /**
     *  Generates a hashkey using reflection
     *
     * @param method
     * @param parameters
     * @return
     */
    public static Integer reflectionHashKey(Method method, Object[] parameters) {

        int hashCode = method.getName().hashCode();

        if (parameters == null || parameters.length == 0) {
            return hashCode;
        }

        if (parameters.length == 1) {
            return 17 * hashCode + (parameters[0] == null ? method.getName().hashCode()
                    : HashCodeBuilder.reflectionHashCode(parameters[0]));
        }

        for (Object object : parameters) {
            hashCode = 31 * hashCode
                    + (object == null ? NULL_PARAM_KEY : HashCodeBuilder.reflectionHashCode(object));
        }

        return hashCode;
    }

    /**
     * Generates a hashkey using the object's own hashCode function
     *
     * @param method
     * @param parameters
     * @return
     */
    public static Integer defaultHashKey(Method method, Object[] parameters) {

        int hashCode = method.getName().hashCode();

        if (parameters == null || parameters.length == 0) {
            return hashCode;
        }

        if (parameters.length == 1) {
            return 17 * hashCode + (parameters[0] == null ? method.getName().hashCode() : parameters[0].hashCode());
        }

        for (Object object : parameters) {
            hashCode = 31 * hashCode + (object == null ? NULL_PARAM_KEY : object.hashCode());
        }

        return hashCode;
    }
}