+ * A line break may be any of "\n", "\r", "\r\n", "\n\r". + *
+ * + * @since 3.0 + */ +public class JavaBreakIterator extends BreakIterator { + + /** + * A run of common characters. + */ + protected static abstract class Run { + /** The length of this run. */ + protected int length; + + public Run() { + init(); + } + + /** + * Returnstrue if this run consumes ch,
+ * false otherwise. If true is returned,
+ * the length of the receiver is adjusted accordingly.
+ *
+ * @param ch the character to test
+ * @return true if ch was consumed
+ */
+ protected boolean consume(char ch) {
+ if (isValid(ch)) {
+ length++;
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * Whether this run accepts that character; does not update state. Called
+ * from the default implementation of consume.
+ *
+ * @param ch the character to test
+ * @return true if ch is accepted
+ */
+ protected abstract boolean isValid(char ch);
+
+ /**
+ * Resets this run to the initial state.
+ */
+ protected void init() {
+ length= 0;
+ }
+ }
+
+ static final class Whitespace extends Run {
+ @Override
+ protected boolean isValid(char ch) {
+ return Character.isWhitespace(ch) && ch != '\n' && ch != '\r';
+ }
+ }
+
+ static final class LineDelimiter extends Run {
+ /** State: INIT -> delimiter -> EXIT. */
+ private char fState;
+ private static final char INIT= '\0';
+ private static final char EXIT= '\1';
+
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#init()
+ */
+ @Override
+ protected void init() {
+ super.init();
+ fState= INIT;
+ }
+
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#consume(char)
+ */
+ @Override
+ protected boolean consume(char ch) {
+ if (!isValid(ch) || fState == EXIT)
+ return false;
+
+ if (fState == INIT) {
+ fState= ch;
+ length++;
+ return true;
+ } else if (fState != ch) {
+ fState= EXIT;
+ length++;
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ @Override
+ protected boolean isValid(char ch) {
+ return ch == '\n' || ch == '\r';
+ }
+ }
+
+ static final class Identifier extends Run {
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#isValid(char)
+ */
+ @Override
+ protected boolean isValid(char ch) {
+ return Character.isJavaIdentifierPart(ch);
+ }
+ }
+
+ static final class CamelCaseIdentifier extends Run {
+ /* states */
+ private static final int S_INIT= 0;
+ private static final int S_LOWER= 1;
+ private static final int S_ONE_CAP= 2;
+ private static final int S_ALL_CAPS= 3;
+ private static final int S_EXIT= 4;
+ private static final int S_EXIT_MINUS_ONE= 5;
+
+ /* character types */
+ private static final int K_INVALID= 0;
+ private static final int K_LOWER= 1;
+ private static final int K_UPPER= 2;
+ private static final int K_OTHER= 3;
+
+ private int fState;
+
+ private final static int[][] MATRIX= new int[][] {
+ // K_INVALID, K_LOWER, K_UPPER, K_OTHER
+ { S_EXIT, S_LOWER, S_ONE_CAP, S_LOWER }, // S_INIT
+ { S_EXIT, S_LOWER, S_EXIT, S_LOWER }, // S_LOWER
+ { S_EXIT, S_LOWER, S_ALL_CAPS, S_LOWER }, // S_ONE_CAP
+ { S_EXIT, S_EXIT_MINUS_ONE, S_ALL_CAPS, S_LOWER }, // S_ALL_CAPS
+ };
+
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#init()
+ */
+ @Override
+ protected void init() {
+ super.init();
+ fState= S_INIT;
+ }
+
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#consumes(char)
+ */
+ @Override
+ protected boolean consume(char ch) {
+ int kind= getKind(ch);
+ fState= MATRIX[fState][kind];
+ switch (fState) {
+ case S_LOWER:
+ case S_ONE_CAP:
+ case S_ALL_CAPS:
+ length++;
+ return true;
+ case S_EXIT:
+ return false;
+ case S_EXIT_MINUS_ONE:
+ length--;
+ return false;
+ default:
+ Assert.isTrue(false);
+ return false;
+ }
+ }
+
+ /**
+ * Determines the kind of a character.
+ *
+ * @param ch the character to test
+ */
+ private int getKind(char ch) {
+ if (Character.isUpperCase(ch))
+ return K_UPPER;
+ if (Character.isLowerCase(ch))
+ return K_LOWER;
+ if (Character.isJavaIdentifierPart(ch)) // _, digits...
+ return K_OTHER;
+ return K_INVALID;
+ }
+
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#isValid(char)
+ */
+ @Override
+ protected boolean isValid(char ch) {
+ return Character.isJavaIdentifierPart(ch);
+ }
+ }
+
+ static final class Other extends Run {
+ /*
+ * @see org.eclipse.jdt.internal.ui.text.JavaBreakIterator.Run#isValid(char)
+ */
+ @Override
+ protected boolean isValid(char ch) {
+ return !Character.isWhitespace(ch) && !Character.isJavaIdentifierPart(ch);
+ }
+ }
+
+ private static final Run WHITESPACE= new Whitespace();
+ private static final Run DELIMITER= new LineDelimiter();
+ private static final Run CAMELCASE= new CamelCaseIdentifier(); // new Identifier();
+ private static final Run OTHER= new Other();
+
+ /** The platform break iterator (word instance) used as a base. */
+ protected final BreakIterator fIterator;
+ /** The text we operate on. */
+ protected CharSequence fText;
+ /** our current position for the stateful methods. */
+ private int fIndex;
+
+
+ /**
+ * Creates a new break iterator.
+ */
+ public JavaBreakIterator() {
+ fIterator= BreakIterator.getWordInstance();
+ fIndex= fIterator.current();
+ }
+
+ /*
+ * @see java.text.BreakIterator#current()
+ */
+ @Override
+ public int current() {
+ return fIndex;
+ }
+
+ /*
+ * @see java.text.BreakIterator#first()
+ */
+ @Override
+ public int first() {
+ fIndex= fIterator.first();
+ return fIndex;
+ }
+
+ /*
+ * @see java.text.BreakIterator#following(int)
+ */
+ @Override
+ public int following(int offset) {
+ // work around too eager IAEs in standard implementation
+ if (offset == getText().getEndIndex())
+ return DONE;
+
+ int next= fIterator.following(offset);
+ if (next == DONE)
+ return DONE;
+
+ // TODO deal with complex script word boundaries
+ // Math.min(offset + run.length, next) does not work
+ // since BreakIterator.getWordInstance considers _ as boundaries
+ // seems to work fine, however
+ Run run= consumeRun(offset);
+ return offset + run.length;
+
+ }
+
+ /**
+ * Consumes a run of characters at the limits of which we introduce a break.
+ * @param offset the offset to start at
+ * @return the run that was consumed
+ */
+ private Run consumeRun(int offset) {
+ // assert offset < length
+
+ char ch= fText.charAt(offset);
+ int length= fText.length();
+ Run run= getRun(ch);
+ while (run.consume(ch) && offset < length - 1) {
+ offset++;
+ ch= fText.charAt(offset);
+ }
+
+ return run;
+ }
+
+ /**
+ * Returns a run based on a character.
+ *
+ * @param ch the character to test
+ * @return the correct character given ch
+ */
+ private Run getRun(char ch) {
+ Run run;
+ if (WHITESPACE.isValid(ch))
+ run= WHITESPACE;
+ else if (DELIMITER.isValid(ch))
+ run= DELIMITER;
+ else if (CAMELCASE.isValid(ch))
+ run= CAMELCASE;
+ else if (OTHER.isValid(ch))
+ run= OTHER;
+ else {
+ Assert.isTrue(false);
+ return null;
+ }
+
+ run.init();
+ return run;
+ }
+
+ /*
+ * @see java.text.BreakIterator#getText()
+ */
+ @Override
+ public CharacterIterator getText() {
+ return fIterator.getText();
+ }
+
+ /*
+ * @see java.text.BreakIterator#isBoundary(int)
+ */
+ @Override
+ public boolean isBoundary(int offset) {
+ if (offset == getText().getBeginIndex())
+ return true;
+ else
+ return following(offset - 1) == offset;
+ }
+
+ /*
+ * @see java.text.BreakIterator#last()
+ */
+ @Override
+ public int last() {
+ fIndex= fIterator.last();
+ return fIndex;
+ }
+
+ /*
+ * @see java.text.BreakIterator#next()
+ */
+ @Override
+ public int next() {
+ fIndex= following(fIndex);
+ return fIndex;
+ }
+
+ /*
+ * @see java.text.BreakIterator#next(int)
+ */
+ @Override
+ public int next(int n) {
+ return fIterator.next(n);
+ }
+
+ /*
+ * @see java.text.BreakIterator#preceding(int)
+ */
+ @Override
+ public int preceding(int offset) {
+ if (offset == getText().getBeginIndex())
+ return DONE;
+
+ if (isBoundary(offset - 1))
+ return offset - 1;
+
+ int previous= offset - 1;
+ do {
+ previous= fIterator.preceding(previous);
+ } while (!isBoundary(previous));
+
+ int last= DONE;
+ while (previous < offset) {
+ last= previous;
+ previous= following(previous);
+ }
+
+ return last;
+ }
+
+ /*
+ * @see java.text.BreakIterator#previous()
+ */
+ @Override
+ public int previous() {
+ fIndex= preceding(fIndex);
+ return fIndex;
+ }
+
+ /*
+ * @see java.text.BreakIterator#setText(java.lang.String)
+ */
+ @Override
+ public void setText(String newText) {
+ setText((CharSequence) newText);
+ }
+
+ /**
+ * Creates a break iterator given a char sequence.
+ * @param newText the new text
+ */
+ public void setText(CharSequence newText) {
+ fText= newText;
+ fIterator.setText(new SequenceCharacterIterator(newText));
+ first();
+ }
+
+ /*
+ * @see java.text.BreakIterator#setText(java.text.CharacterIterator)
+ */
+ @Override
+ public void setText(CharacterIterator newText) {
+ if (newText instanceof CharSequence) {
+ fText= (CharSequence) newText;
+ fIterator.setText(newText);
+ first();
+ } else {
+ throw new UnsupportedOperationException("CharacterIterator not supported"); //$NON-NLS-1$
+ }
+ }
+}