https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.beans.finder;


This class is designed to be a key of a cache
of constructors or methods.

Author:Sergey A. Malenkov
Since:1.7
/**
 * This class is designed to be a key of a cache
 * of constructors or methods.
 *
 * @since 1.7
 *
 * @author Sergey A. Malenkov
 */
final class Signature {
    private final Class<?> type;
    private final String name;
    private final Class<?>[] args;

    private volatile int code;

    
Constructs signature for constructor.

Params:
  • type –  the class that contains constructor
  • args –  the types of constructor's parameters
/**
     * Constructs signature for constructor.
     *
     * @param type  the class that contains constructor
     * @param args  the types of constructor's parameters
     */
    Signature(Class<?> type, Class<?>[] args) {
        this(type, null, args);
    }

    
Constructs signature for method.

Params:
  • type –  the class that contains method
  • name –  the name of the method
  • args –  the types of method's parameters
/**
     * Constructs signature for method.
     *
     * @param type  the class that contains method
     * @param name  the name of the method
     * @param args  the types of method's parameters
     */
    Signature(Class<?> type, String name, Class<?>[] args) {
        this.type = type;
        this.name = name;
        this.args = args;
    }

    Class<?> getType() {
        return this.type;
    }

    String getName() {
        return this.name;
    }

    Class<?>[] getArgs() {
        return this.args;
    }

    
Indicates whether some other object is "equal to" this one.

Params:
  • object –  the reference object with which to compare
See Also:
Returns:true if this object is the same as the object argument, false otherwise
/**
     * Indicates whether some other object is "equal to" this one.
     *
     * @param object  the reference object with which to compare
     * @return {@code true} if this object is the same as the
     *         {@code object} argument, {@code false} otherwise
     * @see #hashCode()
     */
    @Override
    public boolean equals(Object object) {
        if (this == object) {
            return true;
        }
        if (object instanceof Signature) {
            Signature signature = (Signature) object;
            return isEqual(signature.type, this.type)
                && isEqual(signature.name, this.name)
                && isEqual(signature.args, this.args);
        }
        return false;
    }

    
Indicates whether some object is "equal to" another one. This method supports null values. 
Params:
  • obj1 –  the first reference object that will compared
  • obj2 –  the second reference object that will compared
Returns:true if first object is the same as the second object, false otherwise
/**
     * Indicates whether some object is "equal to" another one.
     * This method supports {@code null} values.
     *
     * @param obj1  the first reference object that will compared
     * @param obj2  the second reference object that will compared
     * @return {@code true} if first object is the same as the second object,
     *         {@code false} otherwise
     */
    private static boolean isEqual(Object obj1, Object obj2) {
        return (obj1 == null)
                ? obj2 == null
                : obj1.equals(obj2);
    }

    
Indicates whether some array is "equal to" another one. This method supports null values. 
Params:
  • args1 – the first reference array that will compared
  • args2 – the second reference array that will compared
Returns:true if first array is the same as the second array, false otherwise
/**
     * Indicates whether some array is "equal to" another one.
     * This method supports {@code null} values.
     *
     * @param args1 the first reference array that will compared
     * @param args2 the second reference array that will compared
     * @return {@code true} if first array is the same as the second array,
     *         {@code false} otherwise
     */
    private static boolean isEqual(Class<?>[] args1, Class<?>[] args2) {
        if ((args1 == null) || (args2 == null)) {
            return args1 == args2;
        }
        if (args1.length != args2.length) {
            return false;
        }
        for (int i = 0; i < args1.length; i++) {
            if (!isEqual(args1[i], args2[i])) {
                return false;
            }
        }
        return true;
    }

    
Returns a hash code value for the object. This method is supported for the benefit of hashtables such as HashMap or HashSet. Hash code computed using algorithm suggested in Effective Java, Item 8. 
See Also:
Returns:a hash code value for this object
/**
     * Returns a hash code value for the object.
     * This method is supported for the benefit of hashtables
     * such as {@link java.util.HashMap} or {@link java.util.HashSet}.
     * Hash code computed using algorithm
     * suggested in Effective Java, Item 8.
     *
     * @return a hash code value for this object
     * @see #equals(Object)
     */
    @Override
    public int hashCode() {
        if (this.code == 0) {
            int code = 17;
            code = addHashCode(code, this.type);
            code = addHashCode(code, this.name);

            if (this.args != null) {
                for (Class<?> arg : this.args) {
                    code = addHashCode(code, arg);
                }
            }
            this.code = code;
        }
        return this.code;
    }

    
Adds hash code value if specified object.
This is a part of the algorithm
suggested in Effective Java, Item 8.

Params:
  • code –    current hash code value
  • object –  object that updates hash code value
See Also:
Returns:updated hash code value
/**
     * Adds hash code value if specified object.
     * This is a part of the algorithm
     * suggested in Effective Java, Item 8.
     *
     * @param code    current hash code value
     * @param object  object that updates hash code value
     * @return updated hash code value
     * @see #hashCode()
     */
    private static int addHashCode(int code, Object object) {
        code *= 37;
        return (object != null)
                ? code + object.hashCode()
                : code;
    }
}