package org.eclipse.ui.examples.javaeditor.java;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */

import java.util.ArrayList;
import java.util.List;
import org.eclipse.jface.text.rules.EndOfLineRule;
import org.eclipse.jface.text.rules.ICharacterScanner;
import org.eclipse.jface.text.rules.IPredicateRule;
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.MultiLineRule;
import org.eclipse.jface.text.rules.RuleBasedPartitionScanner;
import org.eclipse.jface.text.rules.RuleBasedScanner;
import org.eclipse.jface.text.rules.SingleLineRule;
import org.eclipse.jface.text.rules.Token;
import org.eclipse.jface.text.rules.WordRule;

/**
 * This scanner recognizes the JavaDoc comments and Java multi line comments.
 */
public class JavaPartitionScanner extends RuleBasedPartitionScanner {

	private final static String SKIP= "__skip"; //$NON-NLS-1$
	public final static String JAVA_MULTILINE_COMMENT= "__java_multiline_comment"; //$NON-NLS-1$
	public final static String JAVA_DOC= "__java_javadoc"; //$NON-NLS-1$

	/**
	 * Detector for empty comments.
	 */
	static class EmptyCommentDetector implements IWordDetector {

		/* (non-Javadoc)
		* Method declared on IWordDetector
	 	*/
		public boolean isWordStart(char c) {
			return (c == '/');
		}

		/* (non-Javadoc)
		* Method declared on IWordDetector
	 	*/
		public boolean isWordPart(char c) {
			return (c == '*' || c == '/');
		}
	};
	
	/**
	 * 
	 */
	static class WordPredicateRule extends WordRule implements IPredicateRule {
		
		private IToken fSuccessToken;
		
		public WordPredicateRule(IToken successToken) {
			super(new EmptyCommentDetector());
			fSuccessToken= successToken;
			addWord("/**/", fSuccessToken);
		}
		
		/*
		 * @see org.eclipse.jface.text.rules.IPredicateRule#evaluate(ICharacterScanner, boolean)
		 */
		public IToken evaluate(ICharacterScanner scanner, boolean resume) {
			return super.evaluate(scanner);
		}

		/*
		 * @see org.eclipse.jface.text.rules.IPredicateRule#getSuccessToken()
		 */
		public IToken getSuccessToken() {
			return fSuccessToken;
		}
	};

	/**
	 * Creates the partitioner and sets up the appropriate rules.
	 */
	public JavaPartitionScanner() {
		super();

		IToken javaDoc= new Token(JAVA_DOC);
		IToken comment= new Token(JAVA_MULTILINE_COMMENT);

		List rules= new ArrayList();

		// Add rule for single line comments.
		rules.add(new EndOfLineRule("//", Token.UNDEFINED)); //$NON-NLS-1$

		// Add rule for strings and character constants.
		rules.add(new SingleLineRule("\"", "\"", Token.UNDEFINED, '\\')); //$NON-NLS-2$ //$NON-NLS-1$
		rules.add(new SingleLineRule("'", "'", Token.UNDEFINED, '\\')); //$NON-NLS-2$ //$NON-NLS-1$

		// Add special case word rule.
		rules.add(new WordPredicateRule(comment));

		// Add rules for multi-line comments and javadoc.
		rules.add(new MultiLineRule("/**", "*/", javaDoc)); //$NON-NLS-1$ //$NON-NLS-2$
		rules.add(new MultiLineRule("/*", "*/", comment)); //$NON-NLS-1$ //$NON-NLS-2$

		IPredicateRule[] result= new IPredicateRule[rules.size()];
		rules.toArray(result);
		setPredicateRules(result);
	}
}