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Added in API level 24

StringSearch

public final class StringSearch
extends SearchIterator

java.lang.Object
↳	android.icu.text.SearchIterator
	↳	android.icu.text.StringSearch

StringSearch is a SearchIterator that provides language-sensitive text searching based on the comparison rules defined in a RuleBasedCollator object. StringSearch ensures that language eccentricity can be handled, e.g. for the German collator, characters ß and SS will be matched if case is chosen to be ignored. See the "ICU Collation Design Document" for more information.

There are 2 match options for selection:
Let S' be the sub-string of a text string S between the offsets start and end [start, end].
A pattern string P matches a text string S at the offsets [start, end] if

 
 option 1. Some canonical equivalent of P matches some canonical equivalent
           of S'
 option 2. P matches S' and if P starts or ends with a combining mark,
           there exists no non-ignorable combining mark before or after S?
           in S respectively.

Option 2. is the default.

This search has APIs similar to that of other text iteration mechanisms such as the break iterators in BreakIterator. Using these APIs, it is easy to scan through text looking for all occurrences of a given pattern. This search iterator allows changing of direction by calling a reset() followed by a next() or previous(). Though a direction change can occur without calling reset() first, this operation comes with some speed penalty. Match results in the forward direction will match the result matches in the backwards direction in the reverse order

SearchIterator provides APIs to specify the starting position within the text string to be searched, e.g. setIndex, preceding and following. Since the starting position will be set as it is specified, please take note that there are some danger points at which the search may render incorrect results:

In the midst of a substring that requires normalization.
If the following match is to be found, the position should not be the second character which requires swapping with the preceding character. Vice versa, if the preceding match is to be found, the position to search from should not be the first character which requires swapping with the next character. E.g certain Thai and Lao characters require swapping.
If a following pattern match is to be found, any position within a contracting sequence except the first will fail. Vice versa if a preceding pattern match is to be found, an invalid starting point would be any character within a contracting sequence except the last.

A BreakIterator can be used if only matches at logical breaks are desired. Using a BreakIterator will only give you results that exactly matches the boundaries given by the BreakIterator. For instance the pattern "e" will not be found in the string "é" if a character break iterator is used.

Options are provided to handle overlapping matches. E.g. In English, overlapping matches produces the result 0 and 2 for the pattern "abab" in the text "ababab", where mutually exclusive matches only produces the result of 0.

Options are also provided to implement "asymmetric search" as described in UTS #10 Unicode Collation Algorithm, specifically the ElementComparisonType values.

Though collator attributes will be taken into consideration while performing matches, there are no APIs here for setting and getting the attributes. These attributes can be set by getting the collator from getCollator() and using the APIs in RuleBasedCollator. Lastly to update StringSearch to the new collator attributes, reset() has to be called.

Restriction:
Currently there are no composite characters that consists of a character with combining class > 0 before a character with combining class == 0. However, if such a character exists in the future, StringSearch does not guarantee the results for option 1.

Consult the SearchIterator documentation for information on and examples of how to use instances of this class to implement text searching.

Note, StringSearch is not to be subclassed.

See also:

Summary

Inherited constants

From class


    android.icu.text.SearchIterator

Inherited fields

From class


    android.icu.text.SearchIterator

Public constructors
`StringSearch(String pattern, CharacterIterator target, RuleBasedCollator collator, BreakIterator breakiter)` Initializes the iterator to use the language-specific rules defined in the argument collator to search for argument pattern in the argument target text.
`StringSearch(String pattern, CharacterIterator target, RuleBasedCollator collator)` Initializes the iterator to use the language-specific rules defined in the argument collator to search for argument pattern in the argument target text.
`StringSearch(String pattern, CharacterIterator target, Locale locale)` Initializes the iterator to use the language-specific rules and break iterator rules defined in the argument locale to search for argument pattern in the argument target text.
`StringSearch(String pattern, CharacterIterator target, ULocale locale)` Initializes the iterator to use the language-specific rules and break iterator rules defined in the argument locale to search for argument pattern in the argument target text.
`StringSearch(String pattern, String target)` Initializes the iterator to use the language-specific rules and break iterator rules defined in the default locale to search for argument pattern in the argument target text.

Public methods
`RuleBasedCollator`	`getCollator()` Gets the `RuleBasedCollator` used for the language rules.
`int`	`getIndex()` Return the current index in the text being searched.
`String`	`getPattern()` Returns the pattern for which `StringSearch` is searching for.
`boolean`	`isCanonical()` Determines whether canonical matches (option 1, as described in the class documentation) is set.
`void`	`reset()` Resets the iteration.
`void`	`setCanonical(boolean allowCanonical)` Set the canonical match mode.
`void`	`setCollator(RuleBasedCollator collator)` Sets the `RuleBasedCollator` to be used for language-specific searching.
`void`	`setIndex(int position)` Sets the position in the target text at which the next search will start.
`void`	`setPattern(String pattern)` Set the pattern to search for.
`void`	`setTarget(CharacterIterator text)` Set the target text to be searched.

Protected methods
`int`	`handleNext(int position)` Abstract method which subclasses override to provide the mechanism for finding the next match in the target text.
`int`	`handlePrevious(int position)` Abstract method which subclasses override to provide the mechanism for finding the previous match in the target text.

Inherited methods

From class


  
    android.icu.text.SearchIterator

`final int`	`first()` Returns the first index at which the string text matches the search pattern.
`final int`	`following(int position)` Returns the first index equal or greater than `position` at which the string text matches the search pattern.
`BreakIterator`	`getBreakIterator()` Returns the BreakIterator that is used to restrict the indexes at which matches are detected.
`SearchIterator.ElementComparisonType`	`getElementComparisonType()` Returns the collation element comparison type.
`abstract int`	`getIndex()` Return the current index in the text being searched.
`int`	`getMatchLength()` Returns the length of text in the string which matches the search pattern.
`int`	`getMatchStart()` Returns the index to the match in the text string that was searched.
`String`	`getMatchedText()` Returns the text that was matched by the most recent call to `first()`, `next()`, `previous()`, or `last()`.
`CharacterIterator`	`getTarget()` Return the string text to be searched.
`abstract int`	`handleNext(int start)` Abstract method which subclasses override to provide the mechanism for finding the next match in the target text.
`abstract int`	`handlePrevious(int startAt)` Abstract method which subclasses override to provide the mechanism for finding the previous match in the target text.
`boolean`	`isOverlapping()` Return true if the overlapping property has been set.
`final int`	`last()` Returns the last index in the target text at which it matches the search pattern.
`int`	`next()` Returns the index of the next point at which the text matches the search pattern, starting from the current position The iterator is adjusted so that its current index (as returned by `getIndex()`) is the match position if one was found.
`final int`	`preceding(int position)` Returns the first index less than `position` at which the string text matches the search pattern.
`int`	`previous()` Returns the index of the previous point at which the string text matches the search pattern, starting at the current position.
`void`	`reset()` Resets the iteration.
`void`	`setBreakIterator(BreakIterator breakiter)` Set the BreakIterator that will be used to restrict the points at which matches are detected.
`void`	`setElementComparisonType(SearchIterator.ElementComparisonType type)` Sets the collation element comparison type.
`void`	`setIndex(int position)` Sets the position in the target text at which the next search will start.
`void`	`setMatchLength(int length)` Sets the length of the most recent match in the target text.
`void`	`setOverlapping(boolean allowOverlap)` Determines whether overlapping matches are returned.
`void`	`setTarget(CharacterIterator text)` Set the target text to be searched.

From class


  
    java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long millis, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long millis)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

Parameters
`pattern`	`String`: text to look for.
`target`	`CharacterIterator`: target text to search for pattern.
`collator`	`RuleBasedCollator`: `RuleBasedCollator` that defines the language rules
`breakiter`	`BreakIterator`: A `BreakIterator` that is used to determine the boundaries of a logical match. This argument can be null.

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StringSearch

Summary

Inherited constants

Inherited fields

Public constructors

Public methods

Protected methods

Inherited methods

Public constructors

StringSearch

StringSearch

StringSearch

StringSearch

StringSearch

Public methods

getCollator

getIndex

getPattern

isCanonical

reset

setCanonical

setCollator

setIndex

setPattern

setTarget

Protected methods

handleNext

handlePrevious