FileHelper.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * Copyright 2005 - 2008 Pentaho Corporation.  All rights reserved.
 *
 * @created Jun 21, 2005 
 * @author James Dixon
 * 
 */

package org.pentaho.platform.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.platform.util.messages.Messages;

public class FileHelper {

  private static final Log logger = LogFactory.getLog(FileHelper.class);

  //private static final int BUFF_SZ = 1024;

  /**
   * 
   * Note: wrap the InputStreamReader in a BufferedReader for efficiency. See:
   * http://java.sun.com/j2se/1.4.2/docs/api/java/io/InputStreamReader.html
   * 
   * @param is
   * @return
   */
  public static String getStringFromInputStream(final InputStream is) {

	try {
		return IOUtils.toString( is );
	} catch (IOException e) {
		logger.error( Messages.getInstance().getErrorString("FileUtil.ERROR_0001_ERROR", e.getMessage()), e); //$NON-NLS-1$
      return null;
    }
  }

  public static String getStringFromFile(final File f) {
    FileInputStream fin = null;
    try {
      fin = new FileInputStream(f);
      return FileHelper.getStringFromInputStream(fin);
    } catch (Exception e) {
    	logger.error(  Messages.getInstance().getErrorString("FileUtil.ERROR_0001_ERROR", e.getMessage()), e); //$NON-NLS-1$
    } finally {
      FileHelper.closeInputStream(fin);
    }
    return null;
  }

  public static byte[] getBytesFromFile(final File file) throws IOException {
    InputStream is = new FileInputStream(file);
    try {
      // Create the byte array to hold the data
      byte[] bytes = IOUtils.toByteArray( is );
      return bytes;
    } finally {
      IOUtils.closeQuietly(is);
    }
  }

  /**
   * Convenience method to close an input stream and handle (log and throw away) any exceptions.
   * Helps keep code uncluttered.
   * 
   * @param strm InputStream to be closed
   */
  public static void closeInputStream(final InputStream strm) {
    if (null != strm) {
      try {
        strm.close();
      } catch (IOException e) {
        logger.warn(Messages.getInstance().getString("FileHelper.WARN_ERROR_CLOSING_STREAM"), e); //$NON-NLS-1$
      }
    }
  }

  /**
   * Convenience method to close a Reader and handle (log and throw away) any exceptions.
   * Helps keep code uncluttered.
   * 
   * @param rdr InputSReadertream to be closed
   */
  public static void closeReader(final Reader rdr) {
    if (null != rdr) {
      try {
        rdr.close();
      } catch (IOException e) {
        logger.warn(Messages.getInstance().getString("FileHelper.WARN_ERROR_CLOSING_READER"), e); //$NON-NLS-1$
      }
    }
  }
}