java.text.BreakIterator
|
JavaTM Platform Standard Ed. 6 |
|||||||||
| 前のクラス 次のクラス | フレームあり フレームなし | |||||||||
| 概要: 入れ子 | フィールド | コンストラクタ | メソッド | 詳細: フィールド | コンストラクタ | メソッド | |||||||||
java.lang.Object
public abstract class BreakIterator
BreakIterator クラスは、テキスト内の境界の位置を見つけるメソッドを実装します。BreakIterator のインスタンスは現在の位置を維持し、テキストをスキャンして境界が発生する文字のインデックスを返します。内部的には、BreakIterator は CharacterIterator を使ってテキストをスキャンするため、このプロトコルを実装する任意のオブジェクトによって保持されるテキストをスキャンできます。StringCharacterIterator は、setText に渡された String オブジェクトのスキャンに使用されます。
このクラスによって提供されるファクトリメソッドを使って、さまざまな型の分割反復子のインスタンスを生成します。特に、単語、行、文、および文字の境界解析を実行する BreakIterator を生成するには、それぞれ getWordIterator、getLineIterator、getSentenceIterator、および getCharacterIterator を使用します。単一の BreakIterator は、1 つのユニット (単語、行、文など) のみを処理するため、実行するユニット境界解析ごとに異なる反復子を使用する必要があります。
行の境界解析では、テキスト文字列を行折り返しで分割する位置を判定します。句読点およびハイフネーションされた単語も、機構により正しく処理されます。実際の行分割は、使用可能な行幅も考慮する必要があるため、より高いレベルのソフトウェアによって処理されます。
文の境界解析では、数字と略語の中のピリオド、さらに引用符や括弧などの終了文字の正しい解釈について選択が可能です。
単語の境界解析は、検索置換機能で使用されます。また、テキスト編集アプリケーション内で、ダブルクリックによって単語が選択可能になります。単語選択では、句読点とともに、記号や句読点などのように単語の一部でない文字、前後に分割のある文字も正しく解釈されます。
文字の境界解析では、たとえばカーソルをテキスト文字列に沿って動かすような場合に、ユーザーが予測するとおりの操作が行われるようにします。文字の境界解析により、文字の格納方法に依存せず、文字列の正しいナビゲーションが可能になります。返される境界は、補助文字、結合文字シーケンス、または合字クラスタの境界になる場合があります。たとえば、アクセント付きの文字は、基準文字と発音区別符号として格納されている場合があります。ユーザーの文字に対する認識は言語間で異なります。
このクラスのファクトリメソッドから返される BreakIterator インスタンスは、自然言語での使用のみを想定しており、プログラミング言語のテキストには使用できません。ただし、プログラミング言語をトークン化するサブクラスを定義することはできます。
例:
テキスト境界を作成し使用します。
public static void main(String args[]) {
if (args.length == 1) {
String stringToExamine = args[0];
//print each word in order
BreakIterator boundary = BreakIterator.getWordInstance();
boundary.setText(stringToExamine);
printEachForward(boundary, stringToExamine);
//print each sentence in reverse order
boundary = BreakIterator.getSentenceInstance(Locale.US);
boundary.setText(stringToExamine);
printEachBackward(boundary, stringToExamine);
printFirst(boundary, stringToExamine);
printLast(boundary, stringToExamine);
}
}
各要素を順に出力します。
public static void printEachForward(BreakIterator boundary, String source) {
int start = boundary.first();
for (int end = boundary.next();
end != BreakIterator.DONE;
start = end, end = boundary.next()) {
System.out.println(source.substring(start,end));
}
}
各要素を逆順に出力します。
public static void printEachBackward(BreakIterator boundary, String source) {
int end = boundary.last();
for (int start = boundary.previous();
start != BreakIterator.DONE;
end = start, start = boundary.previous()) {
System.out.println(source.substring(start,end));
}
}
最初の要素を出力します。
public static void printFirst(BreakIterator boundary, String source) {
int start = boundary.first();
int end = boundary.next();
System.out.println(source.substring(start,end));
}
最後の要素を出力します。
public static void printLast(BreakIterator boundary, String source) {
int end = boundary.last();
int start = boundary.previous();
System.out.println(source.substring(start,end));
}
指定された位置にある要素を出力します。
public static void printAt(BreakIterator boundary, int pos, String source) {
int end = boundary.following(pos);
int start = boundary.previous();
System.out.println(source.substring(start,end));
}
次の単語を検索します。
public static int nextWordStartAfter(int pos, String text) {
BreakIterator wb = BreakIterator.getWordInstance();
wb.setText(text);
int last = wb.following(pos);
int current = wb.next();
while (current != BreakIterator.DONE) {
for (int p = last; p < current; p++) {
if (Character.isLetter(text.codePointAt(p)))
return last;
}
last = current;
current = wb.next();
}
return BreakIterator.DONE;
}
(The iterator returned by BreakIterator.getWordInstance() is unique in that
the break positions it returns don't represent both the start and end of the
thing being iterated over. That is, a sentence-break iterator returns breaks
that each represent the end of one sentence and the beginning of the next.
With the word-break iterator, the characters between two boundaries might be a
word, or they might be the punctuation or whitespace between two words. The
above code uses a simple heuristic to determine which boundary is the beginning
of a word: If the characters between this boundary and the next boundary
include at least one letter (this can be an alphabetical letter, a CJK ideograph,
a Hangul syllable, a Kana character, etc.), then the text between this boundary
and the next is a word; otherwise, it's the material between words.)
CharacterIterator| フィールドの概要 | |
|---|---|
static int |
DONE
DONE is returned by previous(), next(), next(int), preceding(int) and following(int) when either the first or last text boundary has been reached. |
| コンストラクタの概要 | |
|---|---|
protected |
BreakIterator()
Constructor. |
| メソッドの概要 | |
|---|---|
Object |
clone()
Create a copy of this iterator |
abstract int |
current()
Returns character index of the text boundary that was most recently returned by next(), next(int), previous(), first(), last(), following(int) or preceding(int). |
abstract int |
first()
Returns the first boundary. |
abstract int |
following(int offset)
Returns the first boundary following the specified character offset. |
static Locale[] |
getAvailableLocales()
Returns an array of all locales for which the get*Instance methods of this class can return
localized instances. |
static BreakIterator |
getCharacterInstance()
Returns a new BreakIterator instance
for character breaks
for the default locale. |
static BreakIterator |
getCharacterInstance(Locale locale)
Returns a new BreakIterator instance
for character breaks
for the given locale. |
static BreakIterator |
getLineInstance()
Returns a new BreakIterator instance
for line breaks
for the default locale. |
static BreakIterator |
getLineInstance(Locale locale)
Returns a new BreakIterator instance
for line breaks
for the given locale. |
static BreakIterator |
getSentenceInstance()
Returns a new BreakIterator instance
for sentence breaks
for the default locale. |
static BreakIterator |
getSentenceInstance(Locale locale)
Returns a new BreakIterator instance
for sentence breaks
for the given locale. |
abstract CharacterIterator |
getText()
Get the text being scanned |
static BreakIterator |
getWordInstance()
Returns a new BreakIterator instance
for word breaks
for the default locale. |
static BreakIterator |
getWordInstance(Locale locale)
Returns a new BreakIterator instance
for word breaks
for the given locale. |
boolean |
isBoundary(int offset)
Returns true if the specified character offset is a text boundary. |
abstract int |
last()
Returns the last boundary. |
abstract int |
next()
Returns the boundary following the current boundary. |
abstract int |
next(int n)
Returns the nth boundary from the current boundary. |
int |
preceding(int offset)
Returns the last boundary preceding the specified character offset. |
abstract int |
previous()
Returns the boundary preceding the current boundary. |
abstract void |
setText(CharacterIterator newText)
Set a new text for scanning. |
void |
setText(String newText)
Set a new text string to be scanned. |
| クラス java.lang.Object から継承されたメソッド |
|---|
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| フィールドの詳細 |
|---|
public static final int DONE
| コンストラクタの詳細 |
|---|
protected BreakIterator()
| メソッドの詳細 |
|---|
public Object clone()
Object 内の cloneCloneablepublic abstract int first()
public abstract int last()
public abstract int next(int n)
BreakIterator.DONE and the current position is set to either
the first or last text boundary depending on which one is reached. Otherwise,
the iterator's current position is set to the new boundary.
For example, if the iterator's current position is the mth text boundary
and three more boundaries exist from the current boundary to the last text
boundary, the next(2) call will return m + 2. The new text position is set
to the (m + 2)th text boundary. A next(4) call would return
BreakIterator.DONE and the last text boundary would become the
new text position.
n - which boundary to return. A value of 0 does nothing. Negative values move to previous boundaries and positive values move to later boundaries.
BreakIterator.DONE if either first or last text boundary has been reached.public abstract int next()
BreakIterator.DONE and
the iterator's current position is unchanged. Otherwise, the iterator's
current position is set to the boundary following the current boundary.
BreakIterator.DONE if the current boundary is the last text boundary. Equivalent to next(1).next(int)public abstract int previous()
BreakIterator.DONE and
the iterator's current position is unchanged. Otherwise, the iterator's
current position is set to the boundary preceding the current boundary.
BreakIterator.DONE if the current boundary is the first text boundary.public abstract int following(int offset)
BreakIterator.DONE and the iterator's current position is unchanged.
Otherwise, the iterator's current position is set to the returned boundary.
The value returned is always greater than the offset or the value
BreakIterator.DONE.
offset - the character offset to begin scanning.
BreakIterator.DONE if the last text boundary is passed in as the offset.
IllegalArgumentException - if the specified offset is less than the first text boundary or greater than the last text boundary.public int preceding(int offset)
BreakIterator.DONE and the iterator's current position is unchanged.
Otherwise, the iterator's current position is set to the returned boundary.
The value returned is always less than the offset or the value
BreakIterator.DONE.
offset - the characater offset to begin scanning.
BreakIterator.DONE if the first text boundary is passed in as the offset.
IllegalArgumentException - if the specified offset is less than the first text boundary or greater than the last text boundary.public boolean isBoundary(int offset)
offset - the character offset to check.
true if "offset" is a boundary position, false otherwise.public abstract int current()
BreakIterator.DONE because either first or last text boundary
has been reached, it returns the first or last text boundary depending on
which one is reached.
next(),
next(int),
previous(),
first(),
last(),
following(int),
preceding(int)public abstract CharacterIterator getText()
public void setText(String newText)
newText - new text to scan.public abstract void setText(CharacterIterator newText)
newText - new text to scan.public static BreakIterator getWordInstance()
BreakIterator instance
for word breaks
for the default locale.
public static BreakIterator getWordInstance(Locale locale)
BreakIterator instance
for word breaks
for the given locale.
locale - the desired locale
NullPointerException - if locale is nullpublic static BreakIterator getLineInstance()
BreakIterator instance
for line breaks
for the default locale.
public static BreakIterator getLineInstance(Locale locale)
BreakIterator instance
for line breaks
for the given locale.
locale - the desired locale
NullPointerException - if locale is nullpublic static BreakIterator getCharacterInstance()
BreakIterator instance
for character breaks
for the default locale.
public static BreakIterator getCharacterInstance(Locale locale)
BreakIterator instance
for character breaks
for the given locale.
locale - the desired locale
NullPointerException - if locale is nullpublic static BreakIterator getSentenceInstance()
BreakIterator instance
for sentence breaks
for the default locale.
public static BreakIterator getSentenceInstance(Locale locale)
BreakIterator instance
for sentence breaks
for the given locale.
locale - the desired locale
NullPointerException - if locale is nullpublic static Locale[] getAvailableLocales()
get*Instance methods of this class can return
localized instances.
The returned array represents the union of locales supported by the Java
runtime and by installed
BreakIteratorProvider implementations.
It must contain at least a Locale
instance equal to Locale.US.
BreakIterator instances are available.
|
JavaTM Platform Standard Ed. 6 |
|||||||||
| 前のクラス 次のクラス | フレームあり フレームなし | |||||||||
| 概要: 入れ子 | フィールド | コンストラクタ | メソッド | 詳細: フィールド | コンストラクタ | メソッド | |||||||||
Copyright 2009 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Documentation Redistribution Policy も参照してください。