com.mysql.cj.util

Class Util

java.lang.Object

com.mysql.cj.util.Util

public class Util
extends Object

Various utility methods for the driver.

Field Summary

Fields

Modifier and Type	Field and Description
private static ConcurrentMap<Class<?>,Class<?>[]>	implementedInterfacesCache Cache for the implemented interfaces searched.
private static ConcurrentMap<Class<?>,Boolean>	isJdbcInterfaceCache Cache for the JDBC interfaces already verified
private static int	jvmUpdateNumber
private static int	jvmVersion

Constructor Summary

Constructors

Constructor and Description
Util()

Method Summary

Modifier and Type	Method and Description
static Map<Object,Object>	calculateDifferences(Map<?,?> map1, Map<?,?> map2)
static Class<?>[]	getImplementedInterfaces(Class<?> clazz) Retrieves a list with all interfaces implemented by the given class.
static <T> T	getInstance(Class<T> returnType, String className, Class<?>[] argTypes, Object[] args, ExceptionInterceptor exceptionInterceptor) Creates an instance of the specified class name through reflection using the given arguments, as long as the class implements the return type specified.
static int	getJVMUpdateNumber()
static int	getJVMVersion()
static String	getPackageName(Class<?> clazz) Returns the package name of the given class.
static <T> T	handleNewInstance(Constructor<T> ctor, Object[] args, ExceptionInterceptor exceptionInterceptor) Handles constructing new instance with the given constructor and wrapping (or not, as required) the exceptions that could possibly be generated.
static boolean	isCommunityEdition(String serverVersion) Checks whether the given server version string is a MySQL Community edition.
static boolean	isEnterpriseEdition(String serverVersion) Checks whether the given server version string is a MySQL Enterprise/Commercial edition.
static boolean	isJdbcInterface(Class<?> clazz) Recursively checks for interfaces on the given class to determine if it implements a java.sql, javax.sql or com.mysql.cj.jdbc interface.
static boolean	isJdbcPackage(String packageName) Check if the package name is a known JDBC package.
static boolean	isRunningOnWindows() Checks if the JVM is running on Windows Operating System.
static boolean	jvmMeetsMinimum(int version, int updateNumber)
static <T> List<T>	loadClasses(Class<T> instancesType, String extensionClassNames, String errorMessageKey, ExceptionInterceptor exceptionInterceptor)
static int	readBlock(InputStream i, byte[] b, ExceptionInterceptor exceptionInterceptor)
static int	readBlock(InputStream i, byte[] b, int length, ExceptionInterceptor exceptionInterceptor)
static int	readFully(Reader reader, char[] buf, int length) Reads length bytes from reader into buf.
static long	secondsSinceMillis(long timeInMillis) Computes the number of seconds elapsed since the given time in milliseconds.
static String	stackTraceToString(Throwable ex) Converts a nested exception into a nicer message.
static int	truncateAndConvertToInt(long longValue) Converts long to int, truncating to maximum/minimum value if needed.
static int[]	truncateAndConvertToInt(long[] longArray) Converts long[] to int[], truncating to maximum/minimum value if needed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

jvmVersion

private static int jvmVersion

jvmUpdateNumber

private static int jvmUpdateNumber

isJdbcInterfaceCache

private static final ConcurrentMap<Class<?>,Boolean> isJdbcInterfaceCache

Cache for the JDBC interfaces already verified

implementedInterfacesCache

private static final ConcurrentMap<Class<?>,Class<?>[]> implementedInterfacesCache

Cache for the implemented interfaces searched.

Constructor Detail

Util

public Util()

Method Detail

getJVMVersion

public static int getJVMVersion()

jvmMeetsMinimum

public static boolean jvmMeetsMinimum(int version,
                                      int updateNumber)

getJVMUpdateNumber

public static int getJVMUpdateNumber()

isCommunityEdition

public static boolean isCommunityEdition(String serverVersion)

Checks whether the given server version string is a MySQL Community edition.

Parameters:

serverVersion - full server version string

Returns:

true if version does not contain "enterprise", "commercial" or "advanced"

isEnterpriseEdition

public static boolean isEnterpriseEdition(String serverVersion)

Checks whether the given server version string is a MySQL Enterprise/Commercial edition.

Parameters:

serverVersion - full server version string

Returns:

true if version contains "enterprise", "commercial" or "advanced"

stackTraceToString

public static String stackTraceToString(Throwable ex)

Converts a nested exception into a nicer message.

Parameters:

ex - the exception to expand into a message.

Returns:

a message containing the exception, the message (if any), and a stacktrace.

getInstance

public static <T> T getInstance(Class<T> returnType,
                                String className,
                                Class<?>[] argTypes,
                                Object[] args,
                                ExceptionInterceptor exceptionInterceptor)

Creates an instance of the specified class name through reflection using the given arguments, as long as the class implements the return type specified.

Type Parameters:

T - The return type of the new instance.

Parameters:

returnType - the class of the return type of the new instance, usually an interface.

className - the name of the class to instantiate through reflection.

argTypes - the type of the arguments of the constructor to be used for instantiating the class.

args - the arguments to supply when exectuing the new instance constructor.

exceptionInterceptor - the ExceptionInterceptor to handle new exceptions thrown.

Returns:

if all validations succeed, an instance of the class with the specified name.

handleNewInstance

public static <T> T handleNewInstance(Constructor<T> ctor,
                                      Object[] args,
                                      ExceptionInterceptor exceptionInterceptor)

Handles constructing new instance with the given constructor and wrapping (or not, as required) the exceptions that could possibly be generated.

Type Parameters:

T - The type of the new class instance to return.

Parameters:

ctor - constructor

args - arguments for constructor

exceptionInterceptor - exception interceptor

Returns:

object

calculateDifferences

public static Map<Object,Object> calculateDifferences(Map<?,?> map1,
                                                      Map<?,?> map2)

loadClasses

public static <T> List<T> loadClasses(Class<T> instancesType,
                                      String extensionClassNames,
                                      String errorMessageKey,
                                      ExceptionInterceptor exceptionInterceptor)

isJdbcInterface

public static boolean isJdbcInterface(Class<?> clazz)

Recursively checks for interfaces on the given class to determine if it implements a java.sql, javax.sql or com.mysql.cj.jdbc interface.

Parameters:

clazz - The class to investigate.

Returns:

boolean

isJdbcPackage

public static boolean isJdbcPackage(String packageName)

Check if the package name is a known JDBC package.

Parameters:

packageName - The package name to check.

Returns:

boolean

getImplementedInterfaces

public static Class<?>[] getImplementedInterfaces(Class<?> clazz)

Retrieves a list with all interfaces implemented by the given class. If possible gets this information from a cache instead of navigating through the object hierarchy. Results are stored in a cache for future reference.

Parameters:

clazz - The class from which the interface list will be retrieved.

Returns:

An array with all the interfaces for the given class.

secondsSinceMillis

public static long secondsSinceMillis(long timeInMillis)

Computes the number of seconds elapsed since the given time in milliseconds.

Parameters:

timeInMillis - The past instant in milliseconds.

Returns:

The number of seconds, truncated, elapsed since timeInMillis.

truncateAndConvertToInt

public static int truncateAndConvertToInt(long longValue)

Converts long to int, truncating to maximum/minimum value if needed.

Parameters:

longValue - long value

Returns:

int value

truncateAndConvertToInt

public static int[] truncateAndConvertToInt(long[] longArray)

Converts long[] to int[], truncating to maximum/minimum value if needed.

Parameters:

longArray - log values

Returns:

int values

getPackageName

public static String getPackageName(Class<?> clazz)

Returns the package name of the given class. Using clazz.getPackage().getName() is not an alternative because under some class loaders the method getPackage() just returns null.

Parameters:

clazz - the Class from which to get the package name

Returns:

the package name

isRunningOnWindows

public static boolean isRunningOnWindows()

Checks if the JVM is running on Windows Operating System.

Returns:

true if currently running on Windows, false otherwise.

readFully

public static int readFully(Reader reader,
                            char[] buf,
                            int length)
                     throws IOException

Reads length bytes from reader into buf. Blocks until enough input is available

Parameters:

reader - Reader

buf - char array to read into

length - number of chars to read

Returns:

the actual number of chars read

Throws:

IOException - if an error occurs

readBlock

public static final int readBlock(InputStream i,
                                  byte[] b,
                                  ExceptionInterceptor exceptionInterceptor)

readBlock

public static final int readBlock(InputStream i,
                                  byte[] b,
                                  int length,
                                  ExceptionInterceptor exceptionInterceptor)