Class LiterallySignedStringMap
- All Implemented Interfaces:
StringMap<MutableString>
,Function<CharSequence,
,Long> Object2LongFunction<CharSequence>
,Size64
,Serializable
,Function<CharSequence,
,Long> ToLongFunction<CharSequence>
A minimal perfect hash function maps a set of string to an initial segment of the natural
numbers, but will actually map any string to that segment. We can check that
a string is part of the key set by hashing it to a value h, and checking that the h-th
string of the original list does coincide. Since, moreover, this class implements StringMap
,
and thus exposes the original list, we have a two-way
dictionary. In other words, this is a full StringMap
implementation.
Note that some care must be exercised: CharSequence
's contract does not
prescribe equality by content, so if your function behaves badly on some implementations of
CharSequence
you might make the checks fail. To avoid difficulties, the
constructor checks that every string in the list is hashed correctly.
For the same reason, this class implements StringMap<MutableString>
, and
requires that the list of strings provided at construction time is actually a list of
mutable strings.
- Since:
- 2.0
- Author:
- Sebastiano Vigna
- See Also:
-
Field Summary
Modifier and TypeFieldDescriptionprotected final Object2LongFunction<? extends CharSequence>
The underlying map.protected final ObjectBigList<? extends MutableString>
The underlying list.protected final long
The size oflist
.Fields inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction
defRetValue
-
Constructor Summary
ConstructorDescriptionLiterallySignedStringMap
(Object2LongFunction<? extends CharSequence> function, ObjectBigList<? extends MutableString> list) Creates a new shift-add-xor signed string map using a given hash map. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Deprecated.long
ObjectBigList<? extends MutableString>
list()
Returns a list view of the domain of this string map (optional operation).static void
int
size()
Deprecated.long
size64()
Returns the intended number of keys in this function, or -1 if no such number exists.Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction
defaultReturnValue, defaultReturnValue
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2LongFunction
andThen, andThenByte, andThenChar, andThenDouble, andThenFloat, andThenInt, andThenLong, andThenObject, andThenReference, andThenShort, applyAsLong, composeByte, composeChar, composeDouble, composeFloat, composeInt, composeLong, composeObject, composeReference, composeShort, defaultReturnValue, defaultReturnValue, getOrDefault, getOrDefault, put, put, remove, removeLong
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Field Details
-
function
The underlying map. -
list
The underlying list. -
size
protected final long sizeThe size oflist
.
-
-
Constructor Details
-
LiterallySignedStringMap
public LiterallySignedStringMap(Object2LongFunction<? extends CharSequence> function, ObjectBigList<? extends MutableString> list) Creates a new shift-add-xor signed string map using a given hash map.- Parameters:
function
- a function mapping each string inlist
to its ordinal position.list
- a list of strings.
-
-
Method Details
-
getLong
- Specified by:
getLong
in interfaceObject2LongFunction<CharSequence>
-
get
Deprecated.- Specified by:
get
in interfaceFunction<CharSequence,
Long> - Specified by:
get
in interfaceObject2LongFunction<CharSequence>
-
size64
public long size64()Description copied from interface:StringMap
Returns the intended number of keys in this function, or -1 if no such number exists.Most function implementations will have some knowledge of the intended number of keys in their domain. In some cases, however, this might not be possible. This default implementation, in particular, returns -1.
- Specified by:
size64
in interfaceSize64
- Specified by:
size64
in interfaceStringMap<MutableString>
- Returns:
- the intended number of keys in this function, or -1 if that number is not available.
-
size
Deprecated.Description copied from interface:StringMap
- Specified by:
size
in interfaceFunction<CharSequence,
Long> - Specified by:
size
in interfaceSize64
- Specified by:
size
in interfaceStringMap<MutableString>
-
containsKey
- Specified by:
containsKey
in interfaceFunction<CharSequence,
Long>
-
list
Description copied from interface:StringMap
Returns a list view of the domain of this string map (optional operation).Note that the list view acts as an inverse of the mapping implemented by this map.
- Specified by:
list
in interfaceStringMap<MutableString>
- Returns:
- a list view of the domain of this string map, or
null
if this map does not support this operation.
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main
public static void main(String[] arg) throws IOException, JSAPException, ClassNotFoundException, SecurityException, NoSuchMethodException
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