Read number of lines from a File : File Commands « File Input Output « Java
Read number of lines from a File
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
/**
*
* Copyright (c) 2006-2007 Berlin Brown and botnode.com/Berlin Research All Rights Reserved
*
* http://www.opensource.org/licenses/bsd-license.php
* All rights reserved.
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of the Botnode.com (Berlin Brown) nor
* the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Date: 12/15/2009
*
* Home Page: http://botnode.com/
*
* Contact: Berlin Brown <berlin dot brown at gmail.com>
*/
public class Util{
/**
* Routine readLinesFile.
*
* @param inFile File
* @param prefixMode int
* @param prefix String
* @param maxLinesRead int
* @return String
* @throws IOException
*/
public String readLinesFile(final File inFile, final int prefixMode, final String prefix, int maxLinesRead) throws IOException {
final StringBuffer resultBuffer = new StringBuffer(128);
final FileInputStream stream = new FileInputStream(inFile);
final BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
try {
String data = "";
int lineNumber = 1;
boolean maxReached = false;
do {
// Perform simple max, -1 means ignore the max value.
maxReached = (maxLinesRead == -1) ? false : (lineNumber >= maxLinesRead);
data = reader.readLine();
if (data != null) {
final String curPrefix = prefix == null ? "" : prefix;
resultBuffer.append(curPrefix).append(lineNumber).append(':');
resultBuffer.append(inFile.getAbsolutePath()).append(':');
resultBuffer.append(data).append('\n');
}
lineNumber++;
} while((data != null) && !maxReached);
// Add a line number max indicator
if (maxReached) {
resultBuffer.append("...\n");
resultBuffer.append("Max of ").append(lineNumber-1).append(" lines reached for ");
resultBuffer.append(inFile.getAbsolutePath());
resultBuffer.append(data).append('\n');
} // End of the if //
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
;
}
}
} // End of Finally //
return resultBuffer.toString();
}
}
