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();
- }
-}