TokenParser.java

/**********************************************************************
Copyright (c) 2009 Asfun Net.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
 **********************************************************************/
package net.asfun.jangod.parse;

import static net.asfun.jangod.util.logging.JangodLogger;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.Iterator;
import java.util.NoSuchElementException;

import net.asfun.jangod.base.Constants;
import net.asfun.jangod.util.logging.Level;

public class TokenParser implements Iterator<Token> {

    private Tokenizer tm = new Tokenizer();
    private Token token;
    private boolean proceeding = true;

    public TokenParser(String text) {
	tm.init(text);
    }

    public TokenParser(Reader reader) throws ParseException {
	init(reader);
    }

    public void init(String text) {
	tm.init(text);
	token = null;
	proceeding = true;
    }

    public void init(Reader reader) throws ParseException {
	BufferedReader br = new BufferedReader(reader);
	StringBuffer buff = new StringBuffer();
	String line;
	try {
	    while ((line = br.readLine()) != null) {
		buff.append(line);
		buff.append(Constants.STR_NEW_LINE);
	    }
	} catch (IOException e) {
	    throw new ParseException("read template reader fault.",
		    e.getCause());
	} finally {
	    try {
		reader.close();
	    } catch (IOException e) {
		throw new ParseException("read template reader fault.",
			e.getCause());
	    }
	}
	tm.init(buff.toString());
	token = null;
	proceeding = true;
    }

    @Override
    public boolean hasNext() {
	if (proceeding) {
	    try {
		token = tm.getNextToken();
		if (token != null) {
		    return true;
		} else {
		    proceeding = false;
		    return false;
		}
	    } catch (ParseException e) {
		JangodLogger.log(Level.SEVERE, e.getMessage(), e.getCause());
		token = null;
		// TODO go on proceeding or not
	    }
	}
	return false;
    }

    @Override
    public Token next() {
	if (proceeding) {
	    if (token == null) {
		try {
		    Token tk = tm.getNextToken();
		    if (tk == null) {
			proceeding = false;
			throw new NoSuchElementException();
		    }
		    return tk;
		} catch (ParseException e) {
		    JangodLogger
			    .log(Level.SEVERE, e.getMessage(), e.getCause());
		    // TODO go on proceeding or not
		    throw new NoSuchElementException();
		}
	    } else {
		Token last = token;
		token = null;
		return last;
	    }
	}
	throw new NoSuchElementException();
    }

    @Override
    public void remove() {
	throw new UnsupportedOperationException();
    }
}