IOHelper.java

/**
 * Copyright (C) 2003-2008 eXo Platform SAS.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 * 
 * 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see<http://www.gnu.org/licenses/>.
 */

package org.etk.core.rest.impl.provider;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;

/**
 * @author <a href="mailto:andrew00x@gmail.com">Andrey Parfonov</a>
 * @version $Id: $
 */
public final class IOHelper {

  /**
   * Default character set name.
   */
  static final String      DEFAULT_CHARSET_NAME    = "UTF-8";

  /**
   * If character set was not specified then this will be used.
   */
  static final Charset     DEFAULT_CHARSET         = Charset.forName(DEFAULT_CHARSET_NAME);
  
  /**
   * Constructor.
   */
  private IOHelper() {
  }

  /**
   * Write data from {@link InputStream} to {@link OutputStream}.
   * 
   * @param in See {@link InputStream}
   * @param out See {@link OutputStream}
   * @throws IOException if i/o errors occurs
   */
  static void write(InputStream in, OutputStream out) throws IOException {
    byte[] buf = new byte[1024];
    int rd = -1;
    while ((rd = in.read(buf)) != -1)
      out.write(buf, 0, rd);
  }

  /**
   * Write data from {@link Reader} to {@link Writer}.
   * 
   * @param in See {@link Reader}
   * @param out See {@link Writer}
   * @throws IOException if i/o errors occurs
   */
  static void write(Reader in, Writer out) throws IOException {
    char[] buf = new char[1024];
    int rd = -1;
    while ((rd = in.read(buf)) != -1)
      out.write(buf, 0, rd);
  }

  /**
   * Read String from given {@link InputStream}.
   * 
   * @param in source stream for reading
   * @param cs character set, if null then {@link #DEFAULT_CHARSET} will be used
   * @return resulting String
   * @throws IOException if i/o errors occurs
   */
  static String readString(InputStream in, String cs) throws IOException {
    Charset charset;
    // Must respect application specified character set.
    // For output if specified character set is not supported then UTF-8 should
    // be used instead.
    try {
      charset = cs != null ? Charset.forName(cs) : DEFAULT_CHARSET;
    } catch (Exception e) {
      charset = DEFAULT_CHARSET;
    }
    Reader r = new InputStreamReader(in, charset);
    char[] buf = new char[1024];
    StringBuffer sb = new StringBuffer();
    int rd = -1;
    while ((rd = r.read(buf)) != -1)
      sb.append(buf, 0, rd);

    return sb.toString();
  }

  /**
   * Write String to {@link OutputStream}.
   * 
   * @param s String
   * @param out See {@link OutputStream}
   * @param cs character set, if null then {@link #DEFAULT_CHARSET} will be used
   * @throws IOException if i/o errors occurs
   */
  static void writeString(String s, OutputStream out, String cs) throws IOException {
    Charset charset;
    // Must respect application specified character set.
    // For output if specified character set is not supported then UTF-8 should
    // be used instead.
    try {
      charset = cs != null ? Charset.forName(cs) : DEFAULT_CHARSET;
    } catch (Exception e) {
      charset = DEFAULT_CHARSET;
    }
    Writer w = new OutputStreamWriter(out, charset);
    try {
      w.write(s);
    } finally {
      w.flush();
      w.close();
    }
  }

}