jadex.platform.service.dht.ID Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jadex-platform Show documentation
Show all versions of jadex-platform Show documentation
The Jadex platform package contains implementations of platform services as well as the platform component itself.
package jadex.platform.service.dht;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import jadex.bridge.IComponentIdentifier;
import jadex.bridge.service.types.dht.IID;
/**
* This class is an identifier. It is used to represent hash values that are too
* big for primitive data types.
*/
public class ID implements IID {
/**
* Debug field. Setting this to true enables 8-bit hashes (0-255) for better
* readability.
*/
public static boolean DEBUG = true;
/**
* The byte array containing the id information.
*/
protected byte[] id;
/**
* Cached message digest.
*/
private static MessageDigest messageDigest = null;
private static MessageDigest getMessageDigest() {
if (messageDigest == null) {
try {
messageDigest = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
return messageDigest;
}
/**
* Constructor.
*/
public ID() {
}
/**
* Constructor.
*/
public ID(byte[] id) {
this.id = id;
}
/**
* Returns the internal byte array.
*/
public byte[] getId() {
return id;
}
/**
* Sets the internal byte array.
*
* @param id
*/
public void setId(byte[] id) {
this.id = id;
}
/**
* Returns the bytes.
*/
public byte[] getBytes() {
return id;
}
/**
* Returns the length of this ID in bits.
*
* @return
*/
public int getLength() {
return id.length * 8;
}
/**
* Returns a string of the decimal representation of the first
* n bytes of this ID, including leading zeros.
*
* @param numberOfBytes
*
* @return Hex string of ID
*/
public final String toDecimalString(int numberOfBytes) {
// number of displayed bytes must be in interval [1, this.id.length]
int displayBytes = Math.max(1, Math.min(numberOfBytes, this.id.length));
StringBuilder result = new StringBuilder();
for (int i = 0; i < displayBytes; i++) {
String block = Integer.toString(this.id[i] & 0xff);
result.append(block + "");
}
return result.toString();
}
/**
* Subtracts 2^powerOfTwo from the value of this ID and returns the result
* as new ID. Does not modify this instance.
*
* @param powerOfTwo
* exponent to be used for subtraction.
* @return the new ID which is 2^powerOfTwo lower than the current ID modulo
* the maximum ID.
*/
public ID subtractPowerOfTwo(int powerOfTwo) {
if (powerOfTwo < 0 || powerOfTwo >= (this.id.length * 8)) {
throw new IllegalArgumentException(
"The power of two is out of range! It must be in the interval "
+ "[0, length-1]");
}
byte[] copy = new byte[this.id.length];
System.arraycopy(this.id, 0, copy, 0, this.id.length);
// determine index of byte and the value to be added
int indexOfByte = this.id.length - 1 - (powerOfTwo / 8);
byte[] toSub = { 1, 2, 4, 8, 16, 32, 64, -128 };
byte valueToSub = toSub[powerOfTwo % 8];
byte oldValue;
do {
// add value
oldValue = copy[indexOfByte];
copy[indexOfByte] -= valueToSub;
// reset value to 1 for possible overflow situation
valueToSub = 1;
} while (oldValue < 0 && copy[indexOfByte] >= 0 && indexOfByte-- > 0);
return new ID(copy);
}
/**
* Adds 2^powerOfTwo to the value of this ID and returns the result as new
* ID. Does not modify this instance.
*
* @param powerOfTwo
* exponent to be used for subtraction.
* @return the new ID which is 2^powerOfTwo higher than the current ID
* modulo the maximum ID.
*/
public ID addPowerOfTwo(int powerOfTwo) {
if (powerOfTwo < 0 || powerOfTwo >= (this.id.length * 8)) {
throw new IllegalArgumentException(
"The power of two is out of range! It must be in the interval "
+ "[0, length-1]");
}
byte[] copy = new byte[this.id.length];
System.arraycopy(this.id, 0, copy, 0, this.id.length);
// determine index of byte and the value to be added
int indexOfByte = this.id.length - 1 - (powerOfTwo / 8);
byte[] toAdd = { 1, 2, 4, 8, 16, 32, 64, -128 };
byte valueToAdd = toAdd[powerOfTwo % 8];
byte oldValue;
do {
// add value
oldValue = copy[indexOfByte];
copy[indexOfByte] += valueToAdd;
// reset value to 1 for possible overflow situation
valueToAdd = 1;
}
// check for overflow - occurs if old value had a leading one, i.e. it
// was negative, and new value has a leading zero, i.e. it is zero or
// positive; indexOfByte >= 0 prevents running out of the array to the
// left in case of going over the maximum of the ID space
while (oldValue < 0 && copy[indexOfByte] >= 0 && indexOfByte-- > 0);
return new ID(copy);
}
/**
* Check whether this ID is in the given interval.
*
* @param start
* Begin of interval.
* @param end
* End of interval.
* @param leftOpen
* If true, the start value is included in the interval.
* @param rightOpen
* If true, the end value is included in the interval.
* @return true, if this Id is inside the specified interval, else false.
*/
public boolean isInInterval(IID start, IID end, boolean leftOpen,
boolean rightOpen) {
return isInInterval(start, end) || (leftOpen && start.equals(this))
|| (rightOpen && end.equals(this));
}
/**
* Check whether this ID is in the given closed interval.
*
* @param start
* Begin of interval.
* @param end
* End of interval.
* @return true, if this Id is inside the specified interval, else false.
*/
public boolean isInInterval(IID start, IID end) {
if (start.compareTo(end) == 0) {
// from == to -> only bounds excluded
return (this.compareTo(start) != 0);
}
if (start.compareTo(end) < 0) {
// start < end, check if between start + end
return (this.compareTo(start) > 0 && this.compareTo(end) < 0);
} else {
// end < start,
return (this.compareTo(end) < 0) || this.compareTo(start) > 0;
}
}
// public static IID get(final IRingNode node) {
// IID result;
// if (node instanceof IService) {
// result = get(((IService) node).getServiceIdentifier().getProviderId());
// } else {
// // must be local
// if (node != null) {
// result = node.getId().get(2000);
// } else {
// throw new Error("node is null, cannot hash");
// }
// }
// return result;
// }
/**
* Hashes the given CID and returns an ID containing the hash.
*
* @param cid
* CID to hash.
* @return ID Resulting Id.
*/
public static IID get(final IComponentIdentifier cid) {
return get(cid.getName());
}
/**
* Hashes the given string and returns an ID containing the hash.
*
* @param str
* String to hash.
* @return ID Resulting Id.
*/
public static IID get(final String str) {
if (DEBUG) {
// return new ID(new byte[] { Hashing.md5()
// .hashString(str, Charset.defaultCharset())
// .asBytes()[15] });
return new ID(new byte[] {hash(str)[15]});
} else {
return new ID(hash(str));
}
}
/**
*
* Compare this ID with another. If type or length do not match, throw
* ClassCastException.
*
* @return -1 if this ID is smaller, 0 if equal, 1 if greater than the given
* ID.
*
*/
public final int compareTo(IID otherKey) throws ClassCastException {
if (this.getLength() != otherKey.getLength()) {
throw new ClassCastException("IDs with same length can be "
+ "compared! This ID is " + this.getLength()
+ " bits long while the other ID is "
+ otherKey.getLength() + " bits long.");
}
// compare value byte by byte
// byte[] otherBytes = new byte[this.id.length];
// System.arraycopy(otherKey.id, 0, otherBytes, 0, this.id.length);
byte[] otherBytes = otherKey.getBytes();
for (int i = 0; i < this.id.length; i++) {
if ((byte) (this.id[i] - 128) < (byte) (otherBytes[i] - 128)) {
return -1; // this ID is smaller
} else if ((byte) (this.id[i] - 128) > (byte) (otherBytes[i] - 128)) {
return 1; // this ID is greater
}
}
return 0;
}
/**
* Returns a string of the hexadecimal representation of the first
* n bytes of this ID, including leading zeros.
*
* @param numberOfBytes
*
* @return Hex string of ID
*/
public final String toHexString(int numberOfBytes) {
// number of displayed bytes must be in interval [1, this.id.length]
int displayBytes = Math.max(1, Math.min(numberOfBytes, this.id.length));
StringBuilder result = new StringBuilder();
for (int i = 0; i < displayBytes; i++) {
String block = Integer.toHexString(this.id[i] & 0xff).toUpperCase();
// add leading zero to block, if necessary
if (block.length() < 2) {
block = "0" + block;
}
result.append(block + " ");
}
return result.toString();
}
@Override
public boolean equals(Object obj) {
if (obj instanceof ID) {
return ((ID) obj).compareTo(this) == 0;
}
return false;
}
@Override
public int hashCode() {
return Arrays.hashCode(id);
}
@Override
public String toString() {
if (DEBUG) {
int i = (int) id[0] + 128;
return i < 10 ? " " + i : i < 100 ? " " + i : "" + i;
} else {
return toHexString(Integer.MAX_VALUE);
}
}
private static byte[] hash(String str) {
return getMessageDigest().digest(str.getBytes());
}
// @Override
// public IID createNew()
// {
// return new ID(new byte[id.length]);
// }
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy