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ParserContext.java
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ParserContext.java
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/**
* Copyright (C) 2012 Johan Grufman
*
* 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.convx.reader;
import java.io.IOException;
import java.io.Reader;
import java.nio.CharBuffer;
/**
* @author johan
* @since 2011-06-06
*/
public class ParserContext {
private static final int BUFFER_SIZE = 1024;
private Reader reader;
private CharBuffer buffer;
private int lookAhead;
private int position = 0;
private FlatFileLocation flatFileLocation = new FlatFileLocation();
public ParserContext(Reader reader, int lookAhead) {
this(reader, lookAhead, BUFFER_SIZE);
}
public ParserContext(Reader reader, int lookAhead, int bufferSize) {
if (bufferSize < lookAhead) {
throw new IllegalArgumentException("Buffer size must be greater than or equal to look ahead.");
}
this.reader = reader;
this.lookAhead = lookAhead;
buffer = CharBuffer.allocate(bufferSize);
fillBuffer();
}
private void fillBuffer() {
try {
this.reader.read(buffer);
buffer.limit(buffer.position());
} catch (IOException e) {
throw new RuntimeException(e);
}
buffer.rewind();
}
public CharSequence nextCharacters() {
return buffer;
}
public void advance(int length) {
flatFileLocation.advance(buffer.subSequence(0, Math.min(buffer.remaining(), length)));
position += length;
buffer.position(position);
if (buffer.length() < lookAhead) {
buffer.compact();
fillBuffer();
position = 0;
}
}
public boolean hasMoreCharacters() {
return buffer.length() > 0;
}
public char nextCharacter() {
return buffer.charAt(0);
}
public FlatFileLocation getFlatFileLocation() {
return flatFileLocation;
}
public void close() throws IOException {
reader.close();
}
}