IRule capable of detecting words.
+ * + * Word rules also allow for the association of tokens with specific words. That + * is, not only can the rule be used to provide tokens for exact matches, but + * also for the generalized notion of a word in the context in which it is used. + * A word rules uses a word detector to determine what a word is. + *
+ *+ * This word rule allows a word detector to be shared among different word + * matchers. Its up to the word matchers to decide if a word matches and, in + * this a case, which token is associated with that word. + *
+ * + * @see IWordDetector + * @since 3.0 + */ +public class CombinedWordRule implements IRule { + + /** + * Word matcher, that associates matched words with tokens. + */ + public static class WordMatcher { + + /** The table of predefined words and token for this matcher */ + private Map fWords = new HashMap(); + + /** + * Adds a word and the token to be returned if it is detected. + * + * @param word + * the word this rule will search for, may not be + *null
+ * @param token
+ * the token to be returned if the word has been found, may
+ * not be null
+ */
+ public void addWord(String word, IToken token) {
+ Assert.isNotNull(word);
+ Assert.isNotNull(token);
+
+ fWords.put(new CharacterBuffer(word), token);
+ }
+
+ /**
+ * Returns the token associated to the given word and the scanner state.
+ *
+ * @param scanner
+ * the scanner
+ * @param word
+ * the word
+ * @return the token or null if none is associated by
+ * this matcher
+ */
+ public IToken evaluate(ICharacterScanner scanner, CharacterBuffer word) {
+ IToken token = (IToken) fWords.get(word);
+ if (token != null)
+ return token;
+ return Token.UNDEFINED;
+ }
+
+ /**
+ * Removes all words.
+ */
+ public void clearWords() {
+ fWords.clear();
+ }
+ }
+
+ /**
+ * Character buffer, mutable or suitable for use as key in hash
+ * maps.
+ */
+ public static class CharacterBuffer {
+
+ /** Buffer content */
+ private char[] fContent;
+
+ /** Buffer content size */
+ private int fLength = 0;
+
+ /** Is hash code cached? */
+ private boolean fIsHashCached = false;
+
+ /** The hash code */
+ private int fHashCode;
+
+ /**
+ * Initialize with the given capacity.
+ *
+ * @param capacity
+ * the initial capacity
+ */
+ public CharacterBuffer(int capacity) {
+ fContent = new char[capacity];
+ }
+
+ /**
+ * Initialize with the given content.
+ *
+ * @param string
+ * the initial content
+ */
+ public CharacterBuffer(String content) {
+ fContent = content.toCharArray();
+ fLength = content.length();
+ }
+
+ /**
+ * Empties this buffer.
+ */
+ public void clear() {
+ fIsHashCached = false;
+ fLength = 0;
+ }
+
+ /**
+ * Appends the given character to the buffer.
+ *
+ * @param c
+ * the character
+ */
+ public void append(char c) {
+ fIsHashCached = false;
+ if (fLength == fContent.length) {
+ char[] old = fContent;
+ fContent = new char[old.length << 1];
+ System.arraycopy(old, 0, fContent, 0, old.length);
+ }
+ fContent[fLength++] = c;
+ }
+
+ /**
+ * Returns the length of the content.
+ *
+ * @return the length
+ */
+ public int length() {
+ return fLength;
+ }
+
+ /**
+ * Returns the content as string.
+ *
+ * @return the content
+ */
+ public String toString() {
+ return new String(fContent, 0, fLength);
+ }
+
+ /**
+ * Returns the character at the given position.
+ *
+ * @param i
+ * the position
+ * @return the character at position i
+ */
+ public char charAt(int i) {
+ return fContent[i];
+ }
+
+ /*
+ * @see java.lang.Object#hashCode()
+ */
+ public int hashCode() {
+ if (fIsHashCached)
+ return fHashCode;
+
+ int hash = 0;
+ for (int i = 0, n = fLength; i < n; i++)
+ hash = 29 * hash + fContent[i];
+ fHashCode = hash;
+ fIsHashCached = true;
+ return hash;
+ }
+
+ /*
+ * @see java.lang.Object#equals(java.lang.Object)
+ */
+ public boolean equals(Object obj) {
+ if (obj == this)
+ return true;
+ if (!(obj instanceof CharacterBuffer))
+ return false;
+ CharacterBuffer buffer = (CharacterBuffer) obj;
+ int length = buffer.length();
+ if (length != fLength)
+ return false;
+ for (int i = 0; i < length; i++)
+ if (buffer.charAt(i) != fContent[i])
+ return false;
+ return true;
+ }
+
+ /**
+ * Is the content equal to the given string?
+ *
+ * @param string
+ * the string
+ * @return true iff the content is the same character
+ * sequence as in the string
+ */
+ public boolean equals(String string) {
+ int length = string.length();
+ if (length != fLength)
+ return false;
+ for (int i = 0; i < length; i++)
+ if (string.charAt(i) != fContent[i])
+ return false;
+ return true;
+ }
+ }
+
+ /** Internal setting for the uninitialized column constraint */
+ private static final int UNDEFINED = -1;
+
+ /** The word detector used by this rule */
+ private IWordDetector fDetector;
+
+ /**
+ * The default token to be returned on success and if nothing else has been
+ * specified.
+ */
+ private IToken fDefaultToken;
+
+ /** The column constraint */
+ private int fColumn = UNDEFINED;
+
+ /** Buffer used for pattern detection */
+ private CharacterBuffer fBuffer = new CharacterBuffer(16);
+
+ /** List of word matchers */
+ private List fMatchers = new ArrayList();
+
+ /**
+ * Creates a rule which, with the help of an word detector, will return the
+ * token associated with the detected word. If no token has been associated,
+ * the scanner will be rolled back and an undefined token will be returned
+ * in order to allow any subsequent rules to analyze the characters.
+ *
+ * @param detector
+ * the word detector to be used by this rule, may not be
+ * null
+ *
+ * @see #addWord(String, IToken)
+ */
+ public CombinedWordRule(IWordDetector detector) {
+ this(detector, null, Token.UNDEFINED);
+ }
+
+ /**
+ * Creates a rule which, with the help of an word detector, will return the
+ * token associated with the detected word. If no token has been associated,
+ * the specified default token will be returned.
+ *
+ * @param detector
+ * the word detector to be used by this rule, may not be
+ * null
+ * @param defaultToken
+ * the default token to be returned on success if nothing else is
+ * specified, may not be null
+ *
+ * @see #addWord(String, IToken)
+ */
+ public CombinedWordRule(IWordDetector detector, IToken defaultToken) {
+ this(detector, null, defaultToken);
+ }
+
+ /**
+ * Creates a rule which, with the help of an word detector, will return the
+ * token associated with the detected word. If no token has been associated,
+ * the scanner will be rolled back and an undefined token will be returned
+ * in order to allow any subsequent rules to analyze the characters.
+ *
+ * @param detector
+ * the word detector to be used by this rule, may not be
+ * null
+ * @param matcher
+ * the initial word matcher
+ *
+ * @see #addWord(String, IToken)
+ */
+ public CombinedWordRule(IWordDetector detector, WordMatcher matcher) {
+ this(detector, matcher, Token.UNDEFINED);
+ }
+
+ /**
+ * Creates a rule which, with the help of an word detector, will return the
+ * token associated with the detected word. If no token has been associated,
+ * the specified default token will be returned.
+ *
+ * @param detector
+ * the word detector to be used by this rule, may not be
+ * null
+ * @param matcher
+ * the initial word matcher
+ * @param defaultToken
+ * the default token to be returned on success if nothing else is
+ * specified, may not be null
+ *
+ * @see #addWord(String, IToken)
+ */
+ public CombinedWordRule(IWordDetector detector, WordMatcher matcher,
+ IToken defaultToken) {
+
+ Assert.isNotNull(detector);
+ Assert.isNotNull(defaultToken);
+
+ fDetector = detector;
+ fDefaultToken = defaultToken;
+ if (matcher != null)
+ addWordMatcher(matcher);
+ }
+
+ /**
+ * Adds the given matcher.
+ *
+ * @param matcher
+ * the matcher
+ */
+ public void addWordMatcher(WordMatcher matcher) {
+ fMatchers.add(matcher);
+ }
+
+ /**
+ * Sets a column constraint for this rule. If set, the rule's token will
+ * only be returned if the pattern is detected starting at the specified
+ * column. If the column is smaller then 0, the column constraint is
+ * considered removed.
+ *
+ * @param column
+ * the column in which the pattern starts
+ */
+ public void setColumnConstraint(int column) {
+ if (column < 0)
+ column = UNDEFINED;
+ fColumn = column;
+ }
+
+ /*
+ * @see IRule#evaluate(ICharacterScanner)
+ */
+ public IToken evaluate(ICharacterScanner scanner) {
+ int c = scanner.read();
+ if (fDetector.isWordStart((char) c)) {
+ if (fColumn == UNDEFINED || (fColumn == scanner.getColumn() - 1)) {
+
+ fBuffer.clear();
+ do {
+ fBuffer.append((char) c);
+ c = scanner.read();
+ } while (c != ICharacterScanner.EOF
+ && fDetector.isWordPart((char) c));
+ scanner.unread();
+
+ for (int i = 0, n = fMatchers.size(); i < n; i++) {
+ IToken token = ((WordMatcher) fMatchers.get(i)).evaluate(
+ scanner, fBuffer);
+ if (!token.isUndefined())
+ return token;
+ }
+
+ if (fDefaultToken.isUndefined())
+ unreadBuffer(scanner);
+
+ return fDefaultToken;
+ }
+ }
+
+ scanner.unread();
+ return Token.UNDEFINED;
+ }
+
+ /**
+ * Returns the characters in the buffer to the scanner.
+ *
+ * @param scanner
+ * the scanner to be used
+ */
+ private void unreadBuffer(ICharacterScanner scanner) {
+ for (int i = fBuffer.length() - 1; i >= 0; i--)
+ scanner.unread();
+ }
+}