International Components for Unicode for Java (icu4j) 74.2 · com.ibm.icu.text.TransliterationRule

A transliteration rule used by RuleBasedTransliterator. TransliterationRule is an immutable object.

A rule consists of an input pattern and an output string. When the input pattern is matched, the output string is emitted. The input pattern consists of zero or more characters which are matched exactly (the key) and optional context. Context must match if it is specified. Context may be specified before the key, after the key, or both. The key, preceding context, and following context may contain variables. Variables represent a set of Unicode characters, such as the letters a through z. Variables are detected by looking up each character in a supplied variable list to see if it has been so defined.

A rule may contain segments in its input string and segment references in its output string. A segment is a substring of the input pattern, indicated by an offset and limit. The segment may be in the preceding or following context. It may not span a context boundary. A segment reference is a special character in the output string that causes a segment of the input string (not the input pattern) to be copied to the output string. The range of special characters that represent segment references is defined by RuleBasedTransliterator.Data.

Example: The rule "([a-z]) . ([0-9]) > $2 . $1" will change the input string "abc.123" to "ab1.c23".

Field Summary

Modifier and Type	Field and Description
pack-priv static final int	ANCHOR_END
pack-priv static final int	ANCHOR_START Flag attributes.
private StringMatcher	anteContext The match that must occur before the key, or null if there is no preceding context.
private int	anteContextLength The length of the string that must match before the key.
private final RuleBasedTransliterator.Data	data An alias pointer to the data for this rule.
pack-priv byte	flags Miscellaneous attributes.
private StringMatcher	key The matcher object for the key.
private int	keyLength The length of the key.
private UnicodeReplacer	output The object that performs the replacement if the key, anteContext, and postContext are matched.
private String	pattern The string that must be matched, consisting of the anteContext, key, and postContext, concatenated together, in that order.
private StringMatcher	postContext The match that must occur after the key, or null if there is no following context.
pack-priv UnicodeMatcher[]	segments An array of matcher objects corresponding to the input pattern segments.

Constructor Summary

Access Constructor and Description

Access	Constructor and Description
public	TransliterationRule(String input string, including key and optional ante and post context input, int offset into input to end of ante context, or -1 if none. Must be <= input.length() if not -1. anteContextPos, int offset into input to start of post context, or -1 if none. Must be <= input.length() if not -1, and must be >= anteContextPos. postContextPos, String output string output, int offset into output at which cursor is located, or -1 if none. If less than zero, then the cursor is placed after the `output`; that is, -1 is equivalent to `output.length()`. If greater than `output.length()` then an exception is thrown. cursorPos, int an offset to be added to cursorPos to position the cursor either in the ante context, if < 0, or in the post context, if > 0. For example, the rule "abc{def} > \| @@@ xyz;" changes "def" to "xyz" and moves the cursor to before "a". It would have a cursorOffset of -3. cursorOffset, UnicodeMatcher[] array of UnicodeMatcher corresponding to input pattern segments, or null if there are none segs, boolean true if the the rule is anchored on the left to the context start anchorStart, boolean true if the rule is anchored on the right to the context limit anchorEnd, RuleBasedTransliterator.Data theData) Construct a new rule with the given input, output text, and other attributes.

public

TransliterationRule(String

input string, including key and optional ante and post context

input, int

offset into input to end of ante context, or -1 if none. Must be <= input.length() if not -1.

anteContextPos, int

offset into input to start of post context, or -1 if none. Must be <= input.length() if not -1, and must be >= anteContextPos.

postContextPos, String

output string

output, int

offset into output at which cursor is located, or -1 if none. If less than zero, then the cursor is placed after the output; that is, -1 is equivalent to output.length(). If greater than output.length() then an exception is thrown.

cursorPos, int

an offset to be added to cursorPos to position the cursor either in the ante context, if < 0, or in the post context, if > 0. For example, the rule "abc{def} > | @@@ xyz;" changes "def" to "xyz" and moves the cursor to before "a". It would have a cursorOffset of -3.

cursorOffset, UnicodeMatcher[]

array of UnicodeMatcher corresponding to input pattern segments, or null if there are none

segs, boolean

true if the the rule is anchored on the left to the context start

anchorStart, boolean

true if the rule is anchored on the right to the context limit

anchorEnd, RuleBasedTransliterator.Data theData)

Construct a new rule with the given input, output text, and other attributes.

Method Summary

Modifier and Type	Method and Description
pack-priv void	addSourceTargetSet(UnicodeSet filter, UnicodeSet sourceSet, UnicodeSet targetSet, UnicodeSet revisiting) Find the source and target sets, subject to the input filter.
public int	getAnteContextLength() Return the preceding context length.
pack-priv final int	getIndexValue() Internal method.
public boolean	masks(TransliterationRule r2) Return true if this rule masks another rule.
public int	Returns: one of `U_MISMATCH`, `U_PARTIAL_MATCH`, or `U_MATCH`. If incremental is false then U_PARTIAL_MATCH will not be returned. matchAndReplace(Replaceable the text text, Transliterator.Position the position indices pos, boolean if true, test for partial matches that may be completed by additional text inserted at pos.limit. incremental) Attempt a match and replacement at the given position.
pack-priv final boolean	matchesIndexValue(int v) Internal method.
pack-priv static final int	posAfter(Replaceable str, int pos)
pack-priv static final int	posBefore(Replaceable str, int pos)
public String	toRule(boolean escapeUnprintable) Create a source string that represents this rule.
public String	Returns: string representation of this object toString() Overrides java.lang.Object.toString. Return a string representation of this object.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

ANCHOR_END	back to summary
pack-priv static final int ANCHOR_END

ANCHOR_START	back to summary
pack-priv static final int ANCHOR_START Flag attributes.

anteContext	back to summary
private StringMatcher anteContext The match that must occur before the key, or null if there is no preceding context.

anteContextLength	back to summary
private int anteContextLength The length of the string that must match before the key. If zero, then there is no matching requirement before the key. Substring [0,anteContextLength) of pattern is the anteContext.

data	back to summary
private final RuleBasedTransliterator.Data data An alias pointer to the data for this rule. The data provides lookup services for matchers and segments.

flags	back to summary
pack-priv byte flags Miscellaneous attributes.

key	back to summary
private StringMatcher key The matcher object for the key. If null, then the key is empty.

keyLength	back to summary
private int keyLength The length of the key. Substring [anteContextLength, anteContextLength + keyLength) is the key.

output	back to summary
private UnicodeReplacer output The object that performs the replacement if the key, anteContext, and postContext are matched. Never null.

pattern back to summary

pattern	back to summary
private String pattern The string that must be matched, consisting of the anteContext, key, and postContext, concatenated together, in that order. Some components may be empty (zero length). See Also `anteContextLength`, `keyLength`

private String pattern

The string that must be matched, consisting of the anteContext, key, and postContext, concatenated together, in that order. Some components may be empty (zero length).

See Also: anteContextLength, keyLength

postContext	back to summary
private StringMatcher postContext The match that must occur after the key, or null if there is no following context.

segments	back to summary
pack-priv UnicodeMatcher[] segments An array of matcher objects corresponding to the input pattern segments. If there are no segments this is null. N.B. This is a UnicodeMatcher for generality, but in practice it is always a StringMatcher. In the future we may generalize this, but for now we sometimes cast down to StringMatcher.

Constructor Detail

TransliterationRule	back to summary
public TransliterationRule(String input, int anteContextPos, int postContextPos, String output, int cursorPos, int cursorOffset, UnicodeMatcher[] segs, boolean anchorStart, boolean anchorEnd, RuleBasedTransliterator.Data theData) Construct a new rule with the given input, output text, and other attributes. A cursor position may be specified for the output text. Parameters input:String input string, including key and optional ante and post context anteContextPos:int offset into input to end of ante context, or -1 if none. Must be <= input.length() if not -1. postContextPos:int offset into input to start of post context, or -1 if none. Must be <= input.length() if not -1, and must be >= anteContextPos. output:String output string cursorPos:int offset into output at which cursor is located, or -1 if none. If less than zero, then the cursor is placed after the `output`; that is, -1 is equivalent to `output.length()`. If greater than `output.length()` then an exception is thrown. cursorOffset:int an offset to be added to cursorPos to position the cursor either in the ante context, if < 0, or in the post context, if > 0. For example, the rule "abc{def} > \| @@@ xyz;" changes "def" to "xyz" and moves the cursor to before "a". It would have a cursorOffset of -3. segs:UnicodeMatcher[] array of UnicodeMatcher corresponding to input pattern segments, or null if there are none anchorStart:boolean true if the the rule is anchored on the left to the context start anchorEnd:boolean true if the rule is anchored on the right to the context limit

Method Detail

addSourceTargetSet	back to summary
pack-priv void addSourceTargetSet(UnicodeSet filter, UnicodeSet sourceSet, UnicodeSet targetSet, UnicodeSet revisiting) Find the source and target sets, subject to the input filter. There is a known issue with filters containing multiple characters.

getAnteContextLength	back to summary
public int getAnteContextLength() Return the preceding context length. This method is needed to support the `Transliterator` method `getMaximumContextLength()`.

getIndexValue	back to summary
pack-priv final int getIndexValue() Internal method. Returns 8-bit index value for this rule. This is the low byte of the first character of the key, unless the first character of the key is a set. If it's a set, or otherwise can match multiple keys, the index value is -1.

masks	back to summary
public boolean masks(TransliterationRule r2) Return true if this rule masks another rule. If r1 masks r2 then r1 matches any input string that r2 matches. If r1 masks r2 and r2 masks r1 then r1 == r2. Examples: "a>x" masks "ab>y". "a>x" masks "a[b]>y". "[c]a>x" masks "[dc]a>y".

matchAndReplace back to summary

matchAndReplace	back to summary
public int matchAndReplace(Replaceable text, Transliterator.Position pos, boolean incremental) Attempt a match and replacement at the given position. Return the degree of match between this rule and the given text. The degree of match may be mismatch, a partial match, or a full match. A mismatch means at least one character of the text does not match the context or key. A partial match means some context and key characters match, but the text is not long enough to match all of them. A full match means all context and key characters match. If a full match is obtained, perform a replacement, update pos, and return U_MATCH. Otherwise both text and pos are unchanged. Parameters text:Replaceable the text pos:Transliterator.Position the position indices incremental:boolean if true, test for partial matches that may be completed by additional text inserted at pos.limit. Returns:int one of `U_MISMATCH`, `U_PARTIAL_MATCH`, or `U_MATCH`. If incremental is false then U_PARTIAL_MATCH will not be returned.

public int matchAndReplace(Replaceable text, Transliterator.Position pos, boolean incremental)

Attempt a match and replacement at the given position. Return the degree of match between this rule and the given text. The degree of match may be mismatch, a partial match, or a full match. A mismatch means at least one character of the text does not match the context or key. A partial match means some context and key characters match, but the text is not long enough to match all of them. A full match means all context and key characters match. If a full match is obtained, perform a replacement, update pos, and return U_MATCH. Otherwise both text and pos are unchanged.

Parameters

text:Replaceable: the text
pos:Transliterator.Position: the position indices
incremental:boolean: if true, test for partial matches that may be completed by additional text inserted at pos.limit.

Returns:int

one of U_MISMATCH, U_PARTIAL_MATCH, or U_MATCH. If incremental is false then U_PARTIAL_MATCH will not be returned.

matchesIndexValue	back to summary
pack-priv final boolean matchesIndexValue(int v) Internal method. Returns true if this rule matches the given index value. The index value is an 8-bit integer, 0..255, representing the low byte of the first character of the key. It matches this rule if it matches the first character of the key, or if the first character of the key is a set, and the set contains any character with a low byte equal to the index value. If the rule contains only ante context, as in foo)>bar, then it will match any key.

matchesIndexValue

back to summary

pack-priv final boolean matchesIndexValue(int v)

Internal method. Returns true if this rule matches the given index value. The index value is an 8-bit integer, 0..255, representing the low byte of the first character of the key. It matches this rule if it matches the first character of the key, or if the first character of the key is a set, and the set contains any character with a low byte equal to the index value. If the rule contains only ante context, as in foo)>bar, then it will match any key.

posAfter	back to summary
pack-priv static final int posAfter(Replaceable str, int pos)

posBefore	back to summary
pack-priv static final int posBefore(Replaceable str, int pos)

toRule	back to summary
public String toRule(boolean escapeUnprintable) Create a source string that represents this rule. Append it to the given string.

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Return a string representation of this object. Returns:String string representation of this object Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Return a string representation of this object.

Returns:String

string representation of this object

Annotations