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/*
* Anarres C Preprocessor
* Copyright (c) 2007-2008, Shevek
*
* 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 org.anarres.cpp;
import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;
import static org.anarres.cpp.Token.EOF;
/**
* An Iterator for {@link Source Sources},
* returning {@link Token Tokens}.
*/
public class SourceIterator implements Iterator<Token> {
private final Source source;
private Token tok;
public SourceIterator(Source s) {
this.source = s;
this.tok = null;
}
/**
* Rethrows IOException inside IllegalStateException.
*/
private void advance() {
try {
if (tok == null)
tok = source.token();
} catch (LexerException e) {
throw new IllegalStateException(e);
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/**
* Returns true if the enclosed Source has more tokens.
*
* The EOF token is never returned by the iterator.
* @throws IllegalStateException if the Source
* throws a LexerException or IOException
*/
public boolean hasNext() {
advance();
return tok.getType() != EOF;
}
/**
* Returns the next token from the enclosed Source.
*
* The EOF token is never returned by the iterator.
* @throws IllegalStateException if the Source
* throws a LexerException or IOException
*/
public Token next() {
if (!hasNext())
throw new NoSuchElementException();
Token t = this.tok;
this.tok = null;
return t;
}
/**
* Not supported.
*
* @throws UnsupportedOperationException unconditionally.
*/
public void remove() {
throw new UnsupportedOperationException();
}
}
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