org.jlab.coda.cMsg

Class cMsgUtilities

java.lang.Object

org.jlab.coda.cMsg.cMsgUtilities

public class cMsgUtilities
extends java.lang.Object

This class stores methods which are neatly self-contained and may be used in more that one place.

Version:

1.0

Author:

Carl Timmer

Constructor Summary

Constructors

Constructor and Description
cMsgUtilities()

Method Summary

Modifier and Type	Method and Description
static int	bytesToInt(byte[] b, int off) Converts 4 bytes of a byte array into an integer.
static long	bytesToLong(byte[] b, int off) Converts 8 bytes of a byte array into a long.
static short	bytesToShort(byte[] b, int off) Converts 2 bytes of a byte array into a short.
static java.lang.String	constructServerName(java.lang.String s) This method tests its input argument to see if it is in the proper format for a server; namely, "host:port".
static java.util.Collection<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.util.List<java.net.InterfaceAddress>	getAllIpInfo() Get all local IP addresses, broadcast addresses and subnet masks in a single list of InterfaceAddress objects.
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	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 int	getNetworkAddressInt(byte[] addr, short netPrefixLen) Get the network or subnet address (32-bit integer format) of the given IP address (byte array format) for the given netmask (# of bits format).
static java.lang.String	getNetworkAddressString(byte[] addr, short netPrefixLen) Get the network or subnet address as a dotted-decimal string of the given IP address (byte array format) for the given netmask (# of bits format).
static java.lang.String	getNetworkAddressString(java.lang.String hostDottedDecimal, short netPrefixLen) Get the network or subnet address as a dotted-decimal string of the given IP address (dotted-decimal string format) for the given netmask (# of bits format).
static void	intToBytes(int intVal, byte[] b, int off) Copies an integer value into 4 bytes of a 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.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 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 local, preferred subnet are first, those on other local subnets are next, and all others come last.
static void	printBuffer(java.nio.ByteBuffer buf, int position, int words, java.lang.String label) This method takes a byte buffer and prints out the desired number of words from the given position.
static void	printBytes(byte[] array, int offset, int bytes, java.lang.String label) This method takes a byte array and prints out the desired number of bytes from the given index.
static void	printBytes(java.nio.ByteBuffer buf, int position, int bytes, java.lang.String label) This method takes a byte buffer and prints out the desired number of bytes from the given position.
static java.lang.String	printError(int error, int debug) Method that returns and/or prints an error explanation.
static int	readSocketBytes(java.nio.ByteBuffer buffer, java.nio.channels.SocketChannel channel, int bytes, int debug) This methods reads a minimum of number of bytes from a channel into a buffer.
static int	readSocketBytesPlain(java.nio.ByteBuffer buffer, java.nio.channels.SocketChannel channel, int bytes) This methods reads a minimum of number of bytes from a channel into a buffer.
static void	shortToBytes(short val, byte[] b, int off) Copies a short value into 2 bytes of a byte array.
static java.nio.channels.ByteChannel	wrapChannel(java.nio.channels.ByteChannel channel) This method wraps a SocketChannel so that the input and output streams derived from that channel do not block each other (SUN java bug id 4774871).
static java.nio.channels.ByteChannel	wrapChannel2(java.nio.channels.ByteChannel channel)

Methods inherited from class java.lang.Object

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

Constructor Detail

cMsgUtilities

public cMsgUtilities()

Method Detail

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

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

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:

integer value

shortToBytes

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

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

Parameters:

val - short value

b - byte array

off - offset into the byte array

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:

ling value

printBuffer

public static void printBuffer(java.nio.ByteBuffer buf,
                               int position,
                               int words,
                               java.lang.String label)

This method takes a byte buffer and prints out the desired number of words from the given position. Will not print out the extra 1, 2, or 3 bytes left at the end of the buffer.

Parameters:

buf - buffer to print out

position - position of data (bytes) in buffer to start printing

words - number of 32 bit words to print in hex

label - a label to print as header

printBytes

public static void printBytes(java.nio.ByteBuffer buf,
                              int position,
                              int bytes,
                              java.lang.String label)

This method takes a byte buffer and prints out the desired number of bytes from the given position. Prints all bytes.

Parameters:

buf - buffer to print out

position - position of data (bytes) in buffer to start printing (starting from 0)

bytes - number of bytes to print in hex

label - a label to print as header

printBytes

public static void printBytes(byte[] array,
                              int offset,
                              int bytes,
                              java.lang.String label)

This method takes a byte array and prints out the desired number of bytes from the given index. Prints all bytes.

Parameters:

array - byte array to print out

offset - offset into array to start printing

bytes - number of bytes to print in hex

label - a label to print as header

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.Collection<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.

getBroadcastAddress

public static java.lang.String getBroadcastAddress(java.lang.String ip)
                                            throws cMsgException

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 dot-decimal format

Returns:

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

Throws:

cMsgException - if arg is not in dot-decimal format

getAllIpInfo

public static java.util.List<java.net.InterfaceAddress> getAllIpInfo()

Get all local IP addresses, broadcast addresses and subnet masks in a single list of InterfaceAddress objects. This only returns IPv4 info from interfaces which are up and are NOT the loopback.

Returns:

lists of all InterfaceAddress objects which are up and not loopback.

getMatchingLocalIpAddress

public static java.lang.String getMatchingLocalIpAddress(java.lang.String ip)
                                                  throws cMsgException

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:

cMsgException - if arg not in dotted-decimal format

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 local, preferred 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

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

preferredAddress - if not null, it is the preferred local 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 valid, 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. Null if ipAddresses arg is null.

getNetworkAddressInt

public static int getNetworkAddressInt(byte[] addr,
                                       short netPrefixLen)

Get the network or subnet address (32-bit integer format) of the given IP address (byte array format) for the given netmask (# of bits format).

Parameters:

addr - IP address (byte array format)

netPrefixLen - netmask (# of bits format)

Returns:

network or subnet address (32-bit integer format); -1 if bad arg(s)

getNetworkAddressString

public static java.lang.String getNetworkAddressString(byte[] addr,
                                                       short netPrefixLen)

Get the network or subnet address as a dotted-decimal string of the given IP address (byte array format) for the given netmask (# of bits format).

Parameters:

addr - IP address (byte array format)

netPrefixLen - netmask (# of bits format)

Returns:

network or subnet address (dotted-decimal string format); null if bad arg(s)

getNetworkAddressString

public static java.lang.String getNetworkAddressString(java.lang.String hostDottedDecimal,
                                                       short netPrefixLen)

Get the network or subnet address as a dotted-decimal string of the given IP address (dotted-decimal string format) for the given netmask (# of bits format).

Parameters:

hostDottedDecimal - IP address (dotted-decimal string format)

netPrefixLen - netmask (# of bits format)

Returns:

network or subnet address (dotted-decimal string format); null if bad arg(s)

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).

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 arg is name of local host, 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 both args refer to the same host, else false.

wrapChannel2

public static java.nio.channels.ByteChannel wrapChannel2(java.nio.channels.ByteChannel channel)

wrapChannel

public static java.nio.channels.ByteChannel wrapChannel(java.nio.channels.ByteChannel channel)

This method wraps a SocketChannel so that the input and output streams derived from that channel do not block each other (SUN java bug id 4774871). The problem is that a SocketChannel is also a SelectableChannel which has this synchronization issue, and that is eliminated by making it a ByteChannel.

Parameters:

channel - the SelectableChannel which has sync problems

Returns:

a ByteChannel which does not have sync problems

readSocketBytesPlain

public static int readSocketBytesPlain(java.nio.ByteBuffer buffer,
                                       java.nio.channels.SocketChannel channel,
                                       int bytes)
                                throws java.io.IOException

This methods reads a minimum of number of bytes from a channel into a buffer.

Parameters:

buffer - a byte buffer which channel data is read into

channel - nio socket communication channel

bytes - minimum number of bytes to read from channel

Returns:

number of bytes read

Throws:

java.io.IOException - If channel is closed or cannot be read from

readSocketBytes

public static int readSocketBytes(java.nio.ByteBuffer buffer,
                                  java.nio.channels.SocketChannel channel,
                                  int bytes,
                                  int debug)
                           throws java.io.IOException

This methods reads a minimum of number of bytes from a channel into a buffer.

Parameters:

buffer - a byte buffer which channel data is read into

channel - nio socket communication channel

bytes - minimum number of bytes to read from channel

debug - level of debug output

Returns:

number of bytes read

Throws:

java.io.IOException - If channel is closed or cannot be read from

printError

public static java.lang.String printError(int error,
                                          int debug)

Method that returns and/or prints an error explanation.

Parameters:

error - error number

debug - level of debug output

Returns:

error explanation

constructServerName

public static java.lang.String constructServerName(java.lang.String s)
                                            throws cMsgException

This method tests its input argument to see if it is in the proper format for a server; namely, "host:port". If it is, it makes sure the host is in its canonical form.

Parameters:

s - input string of a possible server name

Returns:

an acceptable server name with the canonical form of the host name

Throws:

cMsgException - if input string is not in the proper form (host:port) or the host is unknown