/*******************************************************************************
* Copyright (c) 2000, 2011 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.ui.text;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.text.rules.ICharacterScanner;
import org.eclipse.jface.text.rules.IRule;
import org.eclipse.jface.text.rules.IToken;
import org.eclipse.jface.text.rules.IWordDetector;
import org.eclipse.jface.text.rules.Token;
/**
* An implementation of <code>IRule</code> capable of detecting words.
* <p>
* 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.</p>
* <p>
* 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.
* </p>
*
* @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<CharacterBuffer, IToken> fWords= new HashMap<CharacterBuffer, IToken>();
/**
* 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 <code>null</code>
* @param token the token to be returned if the word has been found, may not be <code>null</code>
*/
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 <code>null</code> if none is associated by this matcher
*/
public IToken evaluate(ICharacterScanner scanner, CharacterBuffer word) {
IToken token= fWords.get(word);
if (token != null)
return token;
return Token.UNDEFINED;
}
/**
* Removes all words.
*/
public void clearWords() {
fWords.clear();
}
}
/**
* Character buffer, mutable <b>or</b> 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 content 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
*/
@Override
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 <code>i</code>
*/
public char charAt(int i) {
return fContent[i];
}
/*
* @see java.lang.Object#hashCode()
*/
@Override
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)
*/
@Override
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 <code>true</code> 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<WordMatcher> fMatchers= new ArrayList<WordMatcher>();
/**
* 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 <code>null</code>
*
* @see WordMatcher#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 <code>null</code>
* @param defaultToken the default token to be returned on success
* if nothing else is specified, may not be <code>null</code>
*
* @see WordMatcher#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 <code>null</code>
* @param matcher the initial word matcher
*
* @see WordMatcher#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 <code>null</code>
* @param matcher the initial word matcher
* @param defaultToken the default token to be returned on success
* if nothing else is specified, may not be <code>null</code>
*
* @see WordMatcher#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= 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();
}
}