package com.ontotext.kim.model;
import java.io.Serializable;
/**
* This class represents an Entity Alias in the form of couple hash codes.<br>
* <br>
* For this representation the text is considered a sequence of plain numeric
* and letter lexemes delimited by optional non-alpha-numeric character
* sequences of arbitrary length. The text of the Alias is considered in two
* forms:<br>
* "Normalized Form" - the letter and number lexemes of the Alias delimited
* by special symbol and concatenated in a string;<br>
* "Plain Form" - the string of the Alias without modifications;<br>
* The Normalized Form string is used to calculate <code>aliasHash1</code> hash
* value and the Plain Form string is used to calculate <code>aliasHash2</code>
* hash value. This couple of hash values are used to identify the presence of
* the Alias in the parsed text.<br>
* The <code>aliasHash1</code> is used for preliminary detection of a possible
* Alias location. Because several Aliases can share same value of
* <code>aliasHash1</code> - it is not stored as member of the
* <code>HashedAlias</code> class, but in the containing structure, which is the
* specially designed class <code>HashRegister</code>.<br>
* <br>
* The <code>aliasHash2</code> hash value is used for final verification and
* is stored inside the <code>HashedAlias</code> class. The searched text
* is processed lexeme-by-lexeme through the class <code>ParsingFrame</code>.
* The <code>aliasHash2</code> is calculated from the plain text of the checked
* text fragment. For fast localization of the text fragment which is
* candidate for matching the Alias, the fields <code>prefLen</code> and
* <code>suffLen</code> are added. They contain the lengths of the
* non-alpha-numeric prefix and suffix of the stored Alias. This couple of
* values is intended for use with the method
* <code>ParsingFrame.setNewPrefSufLen</code><br>
* Last two members of the class <code>HashedAlias</code> are the instance
* and the semantic class identifiers of the Entity corresponding to the Alias.
* They are stored in packed form to save memory.
*
* @author danko
*
*/
public class HashedAlias implements Serializable, Comparable<HashedAlias> {
private static final long serialVersionUID = 4500L;
//===========================
// Hashed alias - data fields
//===========================
/** The hash-code of the whole Alias */
public final int aliasHash2;
/** The size of the symbolic prefix */
public final byte prefLen;
/** The size of the symbolic suffix */
public final byte suffLen;
// Properties of the related Entity
/** The internal class identifier of the Entity */
public final int classID;
/** The compressed instance URI of the Entity*/
public final String shortInstURI;
/**
* This constructor initializes all final fields of the class and checks
* for valid value ranges.
* @param aliasHash2 - the hash-code value derived from the plain Alias text
* @param prefLen - the size of the non-alpha-numeric prefix of the Alias
* @param suffLen - the size of the non-alpha-numeric suffix of the Alias
* @param shortInstURI - the compressed instance identifier
* @param classID - the encoded semantic class identifier
*/
public HashedAlias(int aliasHash2, int prefLen, int suffLen,
String shortInstURI, int classID) {
if (prefLen > 127 || suffLen > 127 )
throw new RuntimeException("Cannot create HashedAlias with" +
"symbolic prefix/suffix longer than 127!");
this.aliasHash2 = aliasHash2;
this.prefLen = (byte) prefLen;
this.suffLen = (byte) suffLen;
this.classID = classID;
this.shortInstURI = shortInstURI;
}
public int compareTo(HashedAlias o) {
if (this.prefLen < o.prefLen) return -1;
else if (this.prefLen == o.prefLen && this.suffLen < o.suffLen) return -1;
else if (this.prefLen == o.prefLen && this.suffLen == o.suffLen
&& this.aliasHash2 < o.aliasHash2) return -1;
else if (this.prefLen == o.prefLen && this.suffLen == o.suffLen
&& this.aliasHash2 == o.aliasHash2) {
// Here null is considered the smallest possible string value
if (this.shortInstURI == null) {
if (o.shortInstURI == null)
return 0;
else
return -1;
}
else {
if (o.shortInstURI == null)
return 1;
else
return this.shortInstURI.compareTo(o.shortInstURI);
}
}
return 1;
}
@Override
public boolean equals(Object obj) {
if (! (obj instanceof HashedAlias) ) return false;
HashedAlias he = (HashedAlias) obj;
return (he.aliasHash2 == this.aliasHash2) && (he.prefLen == this.prefLen)
&& (he.suffLen == this.suffLen) &&
( (he.shortInstURI==null)?
(this.shortInstURI == null):
(he.shortInstURI.equals(this.shortInstURI)));
}
@Override
public String toString() {
return "(" + this.prefLen + "<"+ this.aliasHash2 +">" + this.suffLen + ")"+
this.shortInstURI;
}
}