package hudson.plugins.analysis.util;
import java.io.IOException;
import org.apache.commons.io.LineIterator;
/**
* Creates a hash code from the source code of the warning line and the
* surrounding context.
*
* @author Ulli Hafner
*/
public class ContextHashCode {
/** Number of lines before and after current line to consider. */
private static final int LINES_LOOK_AHEAD = 3;
private static final int BUFFER_SIZE = 1000;
/**
* Creates a hash code from the source code of the warning line and the
* surrounding context.
*
* @param fileName
* the absolute path of the file to read
* @param line
* the line of the warning
* @param encoding
* the encoding of the file, if <code>null</code> or empty then
* the default encoding of the platform is used
* @return a has code of the source code
* @throws IOException
* if the contents of the file could not be read
*/
public int create(final String fileName, final int line, final String encoding) throws IOException {
LineIterator lineIterator = EncodingValidator.readFile(fileName, encoding);
StringBuilder context = new StringBuilder(BUFFER_SIZE);
for (int i = 0; lineIterator.hasNext(); i++) {
String currentLine = lineIterator.nextLine();
if (i >= line - LINES_LOOK_AHEAD) {
context.append(currentLine);
}
if (i > line + LINES_LOOK_AHEAD) {
break;
}
}
lineIterator.close();
return context.toString().hashCode();
}
}