org.jlab.coda.et

Class EtUtils

java.lang.Object

org.jlab.coda.et.EtUtils

public class EtUtils
extends java.lang.Object

Collection of methods to help manipulate bytes in arrays.

Author:

timmer

Constructor Summary

Constructors

Constructor and Description
EtUtils()

Method Summary

Modifier and Type	Method and Description
static int	bytesToInt(byte[] data, java.nio.ByteOrder byteOrder, int off) Turn section of byte array into an int.
static int	bytesToInt(byte[] b, int off) Converts 4 bytes of a byte array into an integer.
static long	bytesToLong(byte[] data, java.nio.ByteOrder byteOrder, int off) Turn section of byte array into a long.
static long	bytesToLong(byte[] b, int off) Converts 8 bytes of a byte array into a long.
static short	bytesToShort(byte[] data, java.nio.ByteOrder byteOrder, int off) Turn section of byte array into a short.
static short	bytesToShort(byte[] b, int off) Converts 2 bytes of a byte array into a short.
static java.util.List<java.lang.String>	getAllBroadcastAddresses() Get all local IP broadcast addresses in a list in dotted-decimal form.
static java.util.Collection<java.lang.String>	getAllIpAddresses() Get all local IP addresses in a list in dotted-decimal form.
static java.lang.String	getBroadcastAddress(java.lang.String ip) Given a local IP address as an argument, this method will return its broadcast or subnet address.
static java.lang.String	getBroadcastAddress2(java.lang.String ip) Given a local IP address as an argument, this method will return its broadcast or subnet address.
static java.lang.String	getMatchingLocalIpAddress(java.lang.String ip) Given an IP address as an argument, this method will return that if it matches one of the local IP addresses.
static void	intToBytes(int intVal, byte[] b, int off) Copies an integer value into 4 bytes of a byte array.
static void	intToBytes(int data, java.nio.ByteOrder byteOrder, byte[] dest, int off) Turn int into byte array.
static byte[]	isDottedDecimal(java.lang.String ipAddress) This method tells whether the given IPv4 address is in dot-decimal notation or not.
static boolean	isHostLocal(java.util.ArrayList<java.lang.String> addrs) Is the given list of IP addresses identical to those of the local host?
static boolean	isHostLocal(java.lang.String hostName) Determine whether a given host name refers to the local host.
static boolean	isHostSame(java.lang.String hostName1, java.lang.String hostName2) Determine whether two given host names refers to the same host.
static void	longToBytes(long longVal, byte[] b, int off) Copies an long (64 bit) value into 8 bytes of a byte array.
static void	longToBytes(long data, java.nio.ByteOrder byteOrder, byte[] dest, int off) Turn long into byte array.
static java.util.List<java.lang.String>	orderIPAddresses(java.util.List<java.lang.String> ipAddresses) Takes a list of dotted-decimal formatted IP address strings and orders them so that those on local subnets are first and others come last.
static java.util.List<java.lang.String>	orderIPAddresses(java.util.List<java.lang.String> ipAddresses, java.util.List<java.lang.String> broadAddresses, java.lang.String preferredAddress) Takes a list of dotted-decimal formatted IP address strings and their corresponding broadcast addresses and orders them so that those on the given local subnet are first, those on other local subnets are next, and all others come last.
static java.util.LinkedHashMap<java.lang.String,java.lang.Boolean>	orderIPAddresses(java.util.List<java.lang.String> ipAddresses, java.util.List<java.lang.String> broadAddresses, java.lang.String preferredAddress, boolean etOnLocalHost) Takes a list of dotted-decimal formatted IP address strings and their corresponding broadcast addresses and orders them so that those on the given local subnet are first, those on other local subnets are next, and all others come last.
static void	shortToBytes(short shortVal, byte[] b, int off) Copies a short value into 2 bytes of a byte array.
static void	shortToBytes(short data, java.nio.ByteOrder byteOrder, byte[] dest, int off) Turn short into byte array.
static void	sleepNanos(long nanoDuration) Spin-yield loop based alternative to Thread.sleep Based on the code of Andy Malakov http://andy-malakov.blogspot.fr/2010/06/alternative-to-threadsleep.html
static void	swapArrayInt(byte[] b, int off) Swaps 4 bytes of a byte array in place.
static void	swapArrayShort(byte[] b, int off) Swaps 2 bytes of a byte array in place.

Methods inherited from class java.lang.Object

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

Constructor Detail

EtUtils

public EtUtils()

Method Detail

sleepNanos

public static void sleepNanos(long nanoDuration)
                       throws java.lang.InterruptedException

Spin-yield loop based alternative to Thread.sleep Based on the code of Andy Malakov http://andy-malakov.blogspot.fr/2010/06/alternative-to-threadsleep.html

Parameters:

nanoDuration - number of nano sec to sleep.

Throws:

java.lang.InterruptedException - if thread interrupted during sleep.

shortToBytes

public static void shortToBytes(short data,
                                java.nio.ByteOrder byteOrder,
                                byte[] dest,
                                int off)

Turn short into byte array. Avoids creation of new byte array with each call.

Parameters:

data - short to convert

byteOrder - byte order of returned bytes (big endian if null)

dest - array in which to store returned bytes

off - offset into dest array where returned bytes are placed

intToBytes

public static void intToBytes(int data,
                              java.nio.ByteOrder byteOrder,
                              byte[] dest,
                              int off)

Turn int into byte array. Avoids creation of new byte array with each call.

Parameters:

data - int to convert

byteOrder - byte order of returned bytes (big endian if null)

dest - array in which to store returned bytes

off - offset into dest array where returned bytes are placed

longToBytes

public static void longToBytes(long data,
                               java.nio.ByteOrder byteOrder,
                               byte[] dest,
                               int off)

Turn long into byte array. Avoids creation of new byte array with each call.

Parameters:

data - long to convert

byteOrder - byte order of returned bytes (big endian if null)

dest - array in which to store returned bytes

off - offset into dest array where returned bytes are placed

shortToBytes

public static void shortToBytes(short shortVal,
                                byte[] b,
                                int off)

Copies a short value into 2 bytes of a byte array.

Parameters:

shortVal - short value

b - byte array

off - offset into the byte array

intToBytes

public static void intToBytes(int intVal,
                              byte[] b,
                              int off)

Copies an integer value into 4 bytes of a byte array.

Parameters:

intVal - integer value

b - byte array

off - offset into the byte array

longToBytes

public static void longToBytes(long longVal,
                               byte[] b,
                               int off)

Copies an long (64 bit) value into 8 bytes of a byte array.

Parameters:

longVal - long value

b - byte array

off - offset into the byte array

bytesToShort

public static short bytesToShort(byte[] data,
                                 java.nio.ByteOrder byteOrder,
                                 int off)

Turn section of byte array into a short.

Parameters:

data - byte array to convert

byteOrder - byte order of supplied bytes (big endian if null)

off - offset into data array

Returns:

short converted from byte array

bytesToInt

public static int bytesToInt(byte[] data,
                             java.nio.ByteOrder byteOrder,
                             int off)

Turn section of byte array into an int.

Parameters:

data - byte array to convert

byteOrder - byte order of supplied bytes (big endian if null)

off - offset into data array

Returns:

int converted from byte array

bytesToLong

public static long bytesToLong(byte[] data,
                               java.nio.ByteOrder byteOrder,
                               int off)

Turn section of byte array into a long.

Parameters:

data - byte array to convert

byteOrder - byte order of supplied bytes (big endian if null)

off - offset into data array

Returns:

long converted from byte array

bytesToShort

public static short bytesToShort(byte[] b,
                                 int off)

Converts 2 bytes of a byte array into a short.

Parameters:

b - byte array

off - offset into the byte array (0 = start at first element)

Returns:

short value

bytesToInt

public static int bytesToInt(byte[] b,
                             int off)

Converts 4 bytes of a byte array into an integer.

Parameters:

b - byte array

off - offset into the byte array (0 = start at first element)

Returns:

integer value

bytesToLong

public static long bytesToLong(byte[] b,
                               int off)

Converts 8 bytes of a byte array into a long.

Parameters:

b - byte array

off - offset into the byte array (0 = start at first element)

Returns:

long value

swapArrayInt

public static void swapArrayInt(byte[] b,
                                int off)

Swaps 4 bytes of a byte array in place.

Parameters:

b - byte array

off - offset into the byte array

swapArrayShort

public static void swapArrayShort(byte[] b,
                                  int off)

Swaps 2 bytes of a byte array in place.

Parameters:

b - byte array

off - offset into the byte array

isHostLocal

public static boolean isHostLocal(java.util.ArrayList<java.lang.String> addrs)
                           throws java.net.UnknownHostException

Is the given list of IP addresses identical to those of the local host?

Parameters:

addrs - list of String (dot decimal) addresses to test

Returns:

true if host is local, else false

Throws:

java.net.UnknownHostException - if host cannot be resolved

isHostLocal

public static boolean isHostLocal(java.lang.String hostName)

Determine whether a given host name refers to the local host.

Parameters:

hostName - host name that is checked to see if its local or not

Returns:

true if the host is local, else false.

isHostSame

public static boolean isHostSame(java.lang.String hostName1,
                                 java.lang.String hostName2)

Determine whether two given host names refers to the same host.

Parameters:

hostName1 - host name that is checked to see if it is the same as the other arg or not.

hostName2 - host name that is checked to see if it is the same as the other arg or not.

Returns:

true if the hosts are the same, else false.

getAllIpAddresses

public static java.util.Collection<java.lang.String> getAllIpAddresses()

Get all local IP addresses in a list in dotted-decimal form. The first IP address in the list is the one associated with the canonical host name.

Returns:

list of all local IP addresses in dotted-decimal form.

getAllBroadcastAddresses

public static java.util.List<java.lang.String> getAllBroadcastAddresses()

Get all local IP broadcast addresses in a list in dotted-decimal form. This only makes sense for IPv4.

Returns:

list of all local IP broadcast addresses in dotted-decimal form.

getMatchingLocalIpAddress

public static java.lang.String getMatchingLocalIpAddress(java.lang.String ip)
                                                  throws org.jlab.coda.et.exception.EtException

Given an IP address as an argument, this method will return that if it matches one of the local IP addresses. Given a broadcast or subnet address it will return a local IP address on that subnet. If there are no matches, null is returned.

Parameters:

ip - IP or subnet address in dotted-decimal format

Returns:

matching local address on the same subnet; else null if no match

Throws:

org.jlab.coda.et.exception.EtException - if arg not in dotted-decimal format

getBroadcastAddress2

public static java.lang.String getBroadcastAddress2(java.lang.String ip)
                                             throws org.jlab.coda.et.exception.EtException

Given a local IP address as an argument, this method will return its broadcast or subnet address. If it already is a broadcast address, that is returned. If address is not local or none can be found, null is returned.

Parameters:

ip - IP or subnet address in dotted-decimal format

Returns:

ip's subnet address; null if it's not local or cannot be found

Throws:

org.jlab.coda.et.exception.EtException - if arg is null or not in dotted-decimal format

getBroadcastAddress

public static java.lang.String getBroadcastAddress(java.lang.String ip)
                                            throws org.jlab.coda.et.exception.EtException

Given a local IP address as an argument, this method will return its broadcast or subnet address. If it already is a broadcast address, that is returned. If address is not local or none can be found, null is returned.

Parameters:

ip - IP or subnet address in dotted-decimal format

Returns:

ip's subnet address; null if it's not local or cannot be found

Throws:

org.jlab.coda.et.exception.EtException - if arg is null or not in dotted-decimal format

orderIPAddresses

public static java.util.List<java.lang.String> orderIPAddresses(java.util.List<java.lang.String> ipAddresses)

Takes a list of dotted-decimal formatted IP address strings and orders them so that those on local subnets are first and others come last. This only works for IPv4.

Parameters:

ipAddresses - list of addresses to order; null if arg is null

Returns:

ordered list of given IP addresses in dotted-decimal form with those on local subnets listed first.

orderIPAddresses

public static java.util.List<java.lang.String> orderIPAddresses(java.util.List<java.lang.String> ipAddresses,
                                                                java.util.List<java.lang.String> broadAddresses,
                                                                java.lang.String preferredAddress)

Takes a list of dotted-decimal formatted IP address strings and their corresponding broadcast addresses and orders them so that those on the given local subnet are first, those on other local subnets are next, and all others come last. This only works for IPv4.

Parameters:

ipAddresses - list of addresses to order; null if arg is null

broadAddresses - list of broadcast addresses - each associated w/ corresponding ip address

preferredAddress - if not null, it is the preferred subnet(broadcast) address used in sorting so that addresses on the given list which exist on the preferred subnet are first on the returned list. If a local, non-subnet ip address is given, it will be converted internally to the subnet it is on.

Returns:

ordered list of given IP addresses in dotted-decimal form with those on the given local subnet listed first, those on other local subnets listed next, and all others last.

orderIPAddresses

public static java.util.LinkedHashMap<java.lang.String,java.lang.Boolean> orderIPAddresses(java.util.List<java.lang.String> ipAddresses,
                                                                                           java.util.List<java.lang.String> broadAddresses,
                                                                                           java.lang.String preferredAddress,
                                                                                           boolean etOnLocalHost)

Takes a list of dotted-decimal formatted IP address strings and their corresponding broadcast addresses and orders them so that those on the given local subnet are first, those on other local subnets are next, and all others come last. This only works for IPv4. Included in the returned linked hashmap is a boolean telling whether the address in the list is on same subnet as the preferred address or not.

Parameters:

ipAddresses - list of addresses to order; null if arg is null

broadAddresses - list of broadcast addresses - each associated w/ corresponding ip address

preferredAddress - if not null, it is the preferred subnet(broadcast) address used in sorting so that addresses on the given list which exist on the preferred subnet are first on the returned list. If a local, non-subnet ip address is given, it will be converted internally to the subnet it is on.

etOnLocalHost - is the ET system that client is trying to connect to, on the local host?

Returns:

ordered linked hashmap of given IP addresses in dotted-decimal form (key) with boolean telling if on same subnet as preferredAddress (value). The addresses on the given local subnet are listed first (boolean = true), then those on other local subnets listed next (boolean = false), finally all others last (boolean = false).

isDottedDecimal

public static byte[] isDottedDecimal(java.lang.String ipAddress)

This method tells whether the given IPv4 address is in dot-decimal notation or not. If it is, then the returned bytes are the address in numeric form, else null is returned. This only works for IPv4.

Parameters:

ipAddress - IPV4 address

Returns:

IPV4 address in numeric form if arg is valid dot-decimal address, else null (in network byte order with highest order byte in element 0).