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java.lang.Objectit.unimi.dsi.mg4j.index.AbstractTermMap
it.unimi.dsi.mg4j.util.MinimalPerfectHash
it.unimi.dsi.mg4j.util.SignedMinimalPerfectHash
it.unimi.dsi.mg4j.util.LiterallySignedMinimalPerfectHash
@Deprecated public class LiterallySignedMinimalPerfectHash
Literally signed order-preserving minimal perfect hash tables.
This class source exemplifies a signed minimal perfect hash table that signes each term with the term itself, thus avoiding false positives. Note that it does not feature constructors for gzip'd files.
Field Summary |
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Fields inherited from class it.unimi.dsi.mg4j.util.MinimalPerfectHash |
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ENLARGEMENT_FACTOR, g, init, m, n, n4, NODE_OVERHEAD, rightShift, t, TERM_THRESHOLD, WEIGHT_UNKNOWN, WEIGHT_UNKNOWN_SORTED_TERMS, weight0, weight1, weight2, weightLength |
Constructor Summary | |
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LiterallySignedMinimalPerfectHash(Iterable<? extends CharSequence> terms)
Deprecated. Creates a new literally signed order-preserving minimal perfect hash table for the given terms, using as many weights as the longest term in the collection. |
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LiterallySignedMinimalPerfectHash(Iterable<? extends CharSequence> terms,
int weightLength)
Deprecated. Creates a new literally signed order-preserving minimal perfect hash table for the given terms using the given number of weights. |
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LiterallySignedMinimalPerfectHash(String termFile,
String encoding)
Deprecated. Creates a new literally signed order-preserving minimal perfect hash table for the given file of terms. |
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LiterallySignedMinimalPerfectHash(String termFile,
String encoding,
int weightLength)
Deprecated. Creates a new literally signed order-preserving minimal perfect hash table for the given file of terms using the given number of weights. |
Method Summary | |
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boolean |
checkSignature(byte[] a,
int off,
int len,
int index)
Deprecated. Checks a signature against a byte-array fragment. |
boolean |
checkSignature(CharSequence word,
int index)
Deprecated. Checks a signature against a character sequence. |
void |
initSignatures(Iterable<? extends CharSequence> terms)
Deprecated. Sets up the signature system from a collection. |
static void |
main(String[] arg)
Deprecated. |
Methods inherited from class it.unimi.dsi.mg4j.util.SignedMinimalPerfectHash |
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asUnsigned, getNumber, getNumber, getNumber |
Methods inherited from class it.unimi.dsi.mg4j.util.MinimalPerfectHash |
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getFromT, getNumber, hash, hasTerms, main, size, weightLength |
Methods inherited from class it.unimi.dsi.mg4j.index.AbstractTermMap |
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getIndex, getTerm, getTerm |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public LiterallySignedMinimalPerfectHash(Iterable<? extends CharSequence> terms, int weightLength)
terms
- some terms to hash; it is assumed that there are
no terms with a common prefix of
weightLength
characters.weightLength
- the number of weights used generating the
intermediate hash functions.MinimalPerfectHash.MinimalPerfectHash(Iterable, int)
public LiterallySignedMinimalPerfectHash(Iterable<? extends CharSequence> terms)
terms
- some terms to hash; it is assumed that they do not contain duplicates.MinimalPerfectHash.MinimalPerfectHash(Iterable)
public LiterallySignedMinimalPerfectHash(String termFile, String encoding, int weightLength)
termFile
- an UTF-8 file containing one term on each line; it is assumed that
it does not contain terms with a common prefix of
weightLength
characters.encoding
- the encoding of wordFile
; if null
, it
is assumed to be the platform default encoding.weightLength
- the number of weights used generating the
intermediate hash functions.MinimalPerfectHash.MinimalPerfectHash(String,String,int)
public LiterallySignedMinimalPerfectHash(String termFile, String encoding)
termFile
- an UTF-8 file containing one term on each line; it is assumed that
it does not contain terms with a common prefix of
weightLength
characters.encoding
- the encoding of wordFile
; if null
, it
is assumed to be the platform default encoding.MinimalPerfectHash.MinimalPerfectHash(String,String)
Method Detail |
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public void initSignatures(Iterable<? extends CharSequence> terms)
SignedMinimalPerfectHash
This abstract method must be overriden by implementing subclasses. It must set up all data structures that are necessary to handle signatures; in particular, it will usually compute signatures for all terms in the given collection.
initSignatures
in class SignedMinimalPerfectHash
terms
- the collection of terms given to the constructor of this class.HashCodeSignedMinimalPerfectHash.initSignatures(Iterable)
,
initSignatures(Iterable)
public boolean checkSignature(CharSequence word, int index)
SignedMinimalPerfectHash
This abstract method must be overriden by implementing subclasses.
It must check whether the signature of the given character sequence matches
the one stored for the index
-th term.
Note that this method and SignedMinimalPerfectHash.checkSignature(byte[], int, int, int)
must
be coherent.
checkSignature
in class SignedMinimalPerfectHash
word
- a character sequence.index
- an integer denoting a term in the indexed collection.
index
-th term.HashCodeSignedMinimalPerfectHash.checkSignature(CharSequence, int)
,
checkSignature(CharSequence,int)
public boolean checkSignature(byte[] a, int off, int len, int index)
SignedMinimalPerfectHash
This abstract method must be overriden by implementing subclasses.
It must check whether the signature of the given byte-array fragment
(interpreted as an ISO-8859-1 string) matches
the one stored for the index
-th term.
Note that this method and SignedMinimalPerfectHash.checkSignature(CharSequence, int)
must
be coherent.
checkSignature
in class SignedMinimalPerfectHash
a
- a byte array.off
- the first valid byte in a
.len
- the number of bytes composing the term, starting at off
.
len
bytes starting at off
(interpreted
as ISO-8859-1 characters) matches the one stored for the index
-th term.HashCodeSignedMinimalPerfectHash.checkSignature(CharSequence, int)
,
checkSignature(CharSequence,int)
public static void main(String[] arg) throws InstantiationException, IllegalAccessException, InvocationTargetException, NoSuchMethodException, IOException, com.martiansoftware.jsap.JSAPException, ClassNotFoundException
InstantiationException
IllegalAccessException
InvocationTargetException
NoSuchMethodException
IOException
com.martiansoftware.jsap.JSAPException
ClassNotFoundException
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