com.github.dreamroute.reflect.ClassUtil Maven / Gradle / Ivy

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package com.github.dreamroute.reflect;

import java.lang.reflect.Method;
import java.lang.reflect.ReflectPermission;
import java.util.HashMap;
import java.util.Map;

/**
 * 
 * @author w.dehai
 *
 */
public class ClassUtil {

    private ClassUtil() {}

    public static Map getClassMethods(Class cls) {
        Map uniqueMethods = new HashMap<>();
        Class currentClass = cls;
        while (currentClass != null && currentClass != Object.class) {
            addUniqueMethods(uniqueMethods, currentClass.getDeclaredMethods());

            // we also need to look for interface methods -
            // because the class may be abstract
            Class[] interfaces = currentClass.getInterfaces();
            for (Class anInterface : interfaces) {
                addUniqueMethods(uniqueMethods, anInterface.getMethods());
            }

            currentClass = currentClass.getSuperclass();
        }

        return uniqueMethods;
    }

    private static void addUniqueMethods(Map uniqueMethods, Method[] methods) {
        for (Method currentMethod : methods) {
            if (!currentMethod.isBridge()) {
                String signature = getSignature(currentMethod);
                // check to see if the method is already known
                // if it is known, then an extended class must have
                // overridden a method
                if (!uniqueMethods.containsKey(signature)) {
                    if (canAccessPrivateMethods()) {
                        try {
                            currentMethod.setAccessible(true);
                        } catch (Exception e) {
                            // Ignored. This is only a final precaution, nothing we can do.
                        }
                    }

                    uniqueMethods.put(signature, currentMethod);
                }
            }
        }
    }

    public static String getSignature(Method method) {
        StringBuilder sb = new StringBuilder();
        Class returnType = method.getReturnType();
        if (returnType != null) {
            sb.append(returnType.getName()).append('#');
        }
        sb.append(method.getName());
        Class[] parameters = method.getParameterTypes();
        for (int i = 0; i < parameters.length; i++) {
            if (i == 0) {
                sb.append(':');
            } else {
                sb.append(',');
            }
            sb.append(parameters[i].getName());
        }
        return sb.toString();
    }

    public static boolean canAccessPrivateMethods() {
        try {
            SecurityManager securityManager = System.getSecurityManager();
            if (null != securityManager) {
                securityManager.checkPermission(new ReflectPermission("suppressAccessChecks"));
            }
        } catch (SecurityException e) {
            return false;
        }
        return true;
    }

}