Package com.ctc.wstx.util
Class WordResolver
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- com.ctc.wstx.util.WordResolver
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public final class WordResolver extends java.lang.Object
A specialized Map/Symbol table - like data structure that can be used for both checking whether a word (passed in as a char array) exists in certain set of words AND getting that word as a String. It is reasonably efficient both time and speed-wise, at least for certain use cases; specifically, if there is no existing key to use, it is more efficient way to get to a shared copy of that String The general usage pattern is expected to be such that most checks are positive, ie. that the word indeed is contained in the structure.Although this is an efficient data struct for specific set of usage patterns, one restriction is that the full set of words to include has to be known before constructing the instnace. Also, the size of the set is limited to total word content of about 20k characters.
TODO: Should document the internal data structure...
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Nested Class Summary
Nested Classes Modifier and Type Class Description private static class
WordResolver.Builder
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Field Summary
Fields Modifier and Type Field Description (package private) static char
CHAR_NULL
static int
MAX_WORDS
Maximum number of words (Strings) an instance can contain(package private) char[]
mData
Compressed presentation of the word set.(package private) static int
MIN_BINARY_SEARCH
This is actually just a guess; but in general linear search should be faster for short sequences (definitely for 4 or less; maybe up to 8 or less?)(package private) java.lang.String[]
mWords
Array of actual words returned resolved for matches.(package private) static int
NEGATIVE_OFFSET
Offset added to numbers to mark 'negative' numbers.
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Constructor Summary
Constructors Modifier Constructor Description private
WordResolver(java.lang.String[] words, char[] index)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static WordResolver
constructInstance(java.util.TreeSet<java.lang.String> wordSet)
Tries to construct an instance given ordered set of words.java.lang.String
find(char[] str, int start, int end)
java.lang.String
find(java.lang.String str)
private java.lang.String
findFromOne(char[] str, int start, int end)
int
size()
java.lang.String
toString()
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Field Detail
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MAX_WORDS
public static final int MAX_WORDS
Maximum number of words (Strings) an instance can contain- See Also:
- Constant Field Values
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CHAR_NULL
static final char CHAR_NULL
- See Also:
- Constant Field Values
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NEGATIVE_OFFSET
static final int NEGATIVE_OFFSET
Offset added to numbers to mark 'negative' numbers. Asymmetric, since range of negative markers needed is smaller than positive numbers...- See Also:
- Constant Field Values
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MIN_BINARY_SEARCH
static final int MIN_BINARY_SEARCH
This is actually just a guess; but in general linear search should be faster for short sequences (definitely for 4 or less; maybe up to 8 or less?)- See Also:
- Constant Field Values
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mData
final char[] mData
Compressed presentation of the word set.
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mWords
final java.lang.String[] mWords
Array of actual words returned resolved for matches.
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Method Detail
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constructInstance
public static WordResolver constructInstance(java.util.TreeSet<java.lang.String> wordSet)
Tries to construct an instance given ordered set of words.Note: currently maximum number of words that can be contained is limited to
MAX_WORDS
; additionally, maximum length of all such words can not exceed roughly 28000 characters.- Returns:
- WordResolver constructed for given set of words, if the word set size is not too big; null to indicate "too big" instance.
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size
public int size()
- Returns:
- Number of words contained
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find
public java.lang.String find(char[] str, int start, int end)
- Parameters:
str
- Character array that contains the word to findstart
- Index of the first character of the wordend
- Index following the last character of the word, so thatend - start
equals word length (similar to the wayString.substring()
has).- Returns:
- (Shared) string instance of the word, if it exists in the word set; null if not.
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findFromOne
private java.lang.String findFromOne(char[] str, int start, int end)
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find
public java.lang.String find(java.lang.String str)
- Returns:
- (Shared) string instance of the word, if it exists in the word set; null if not.
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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