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From henn...@apache.org
Subject cvs commit: jakarta-commons-sandbox/configuration/src/java/org/apache/commons/configuration BasePropertiesConfiguration.java
Date Sat, 14 Dec 2002 11:33:46 GMT
henning     2002/12/14 03:33:46

  Added:       configuration/src/java/org/apache/commons/configuration
                        BasePropertiesConfiguration.java
  Log:
  - moved from PropertiesConfiguration
  - factored out the code that is necessary to open a PropertyStream
  - changed the EOF logic from throwing a NullPointerException (and later
    catch it) to actually check for the null value from the reader and
    react accordingly
  - moved to StringUtils.split() from the check for the "=" sign
  - clean up split logic to use "continue" and "break" to escape and
    continue in the property reading loop and the PropertyReader
  - make "include = file1, file2, file3" work
  - Allow derived classes to lock including (when the created object has
    no backing file or resource and include has no real meaning)
  - various comment and style cleanups
  
  Revision  Changes    Path
  1.1                  jakarta-commons-sandbox/configuration/src/java/org/apache/commons/configuration/BasePropertiesConfiguration.java
  
  Index: BasePropertiesConfiguration.java
  ===================================================================
  package org.apache.commons.configuration;
  
  /* ====================================================================
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999-2002 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. 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.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Commons", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
   * ITS 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 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  
  import java.io.File;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.LineNumberReader;
  import java.io.Reader;
  import java.io.UnsupportedEncodingException;
  
  import java.util.Date;
  import java.util.Iterator;
  
  import org.apache.commons.lang.StringUtils;
  
  /**
   * loads the configuration from a properties file. <p>
   *
   * <p>The properties file syntax is explained here:
   *
   * <ul>
   *  <li>
   *   Each property has the syntax <code>key = value</code>
   *  </li>
   *  <li>
   *   The <i>key</i> may use any character but the equal sign '='.
   *  </li>
   *  <li>
   *   <i>value</i> may be separated on different lines if a backslash
   *   is placed at the end of the line that continues below.
   *  </li>
   *  <li>
   *   If <i>value</i> is a list of strings, each token is separated
   *   by a comma ','.
   *  </li>
   *  <li>
   *   Commas in each token are escaped placing a backslash right before
   *   the comma.
   *  </li>
   *  <li>
   *   If a <i>key</i> is used more than once, the values are appended
   *   like if they were on the same line separated with commas.
   *  </li>
   *  <li>
   *   Blank lines and lines starting with character '#' are skipped.
   *  </li>
   *  <li>
   *   If a property is named "include" (or whatever is defined by
   *   setInclude() and getInclude() and the value of that property is
   *   the full path to a file on disk, that file will be included into
   *   the ConfigurationsRepository. You can also pull in files relative
   *   to the parent configuration file. So if you have something
   *   like the following:
   *
   *   include = additional.properties
   *
   *   Then "additional.properties" is expected to be in the same
   *   directory as the parent configuration file.
   *
   *   Duplicate name values will be replaced, so be careful.
   *
   *  </li>
   * </ul>
   *
   * <p>Here is an example of a valid extended properties file:
   *
   * <p><pre>
   *      # lines starting with # are comments
   *
   *      # This is the simplest property
   *      key = value
   *
   *      # A long property may be separated on multiple lines
   *      longvalue = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
   *                  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
   *
   *      # This is a property with many tokens
   *      tokens_on_a_line = first token, second token
   *
   *      # This sequence generates exactly the same result
   *      tokens_on_multiple_lines = first token
   *      tokens_on_multiple_lines = second token
   *
   *      # commas may be escaped in tokens
   *      commas.excaped = Hi\, what'up?
   * </pre>
   *
   * @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>
   * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
   * @author <a href="mailto:daveb@miceda-data">Dave Bryson</a>
   * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
   * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
   * @author <a href="mailto:kjohnson@transparent.com">Kent Johnson</a>
   * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
   * @author <a href="mailto:ipriha@surfeu.fi">Ilkka Priha</a>
   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
   * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
   * @version $Id: BasePropertiesConfiguration.java,v 1.1 2002/12/14 11:33:46 henning Exp
$
   */
  public abstract class BasePropertiesConfiguration
      extends BaseConfiguration
  {
      /** Allow file inclusion or not */
      private boolean includesAllowed = false;
  
      /**
       * This is the name of the property that can point to other
       * properties file for including other properties files.
       */
      protected static String include = "include";
  
      /**
       * Implementations of this class must implement this method.
       *
       * @param resourceName The Resource to load
       * @return An Input Stream
       *
       * @throws IOException Error while loading the properties file
       */
      protected abstract InputStream getPropertyStream(String resourceName)
          throws IOException;
  
      /**
       * Load the properties from the given input stream.
       *
       * @param input An InputStream.
       * @throws IOException
       */
      public void load(InputStream input)
          throws IOException
      {
          load(input, null);
      }
  
      /**
       * Load the properties from the given input stream and using the specified
       * encoding.
       *
       * @param input An InputStream.
       * @param enc An encoding.
       * @exception IOException
       */
      public synchronized void load(InputStream input, String enc)
          throws IOException
      {
          PropertiesReader reader = null;
          if (enc != null)
          {
              try
              {
                  reader =
                    new PropertiesReader(new InputStreamReader(input, enc));
              }
              catch (UnsupportedEncodingException e)
              {
                  // Get one with the default encoding...
              }
          }
  
          if (reader == null)
          {
              reader = new PropertiesReader(new InputStreamReader(input));
          }
  
          while (true)
          {
              String line = reader.readProperty();
              
              if (line == null)
              {
                  break; // EOF
              }
              
              String [] parts = StringUtils.split(line, "=");
              
              if (parts.length >= 2)
              {
                  String key   = parts[0].trim();
                  String value = parts[1].trim();
                  
                  /*
                   * Configure produces lines like this ... just
                   * ignore them.
                   */
                  if (StringUtils.isEmpty(value))
                  {
                      continue; // do .. while
                  }
                  
                  if (StringUtils.isNotEmpty(getInclude())
                      && key.equalsIgnoreCase(getInclude()))
                  {
                      if (getIncludesAllowed())
                      {
                          String [] files = StringUtils.split(value, ",");
                          for (int cnt = 0 ; cnt < files.length ; cnt++)
                          {
                              load(getPropertyStream(files[cnt].trim()));
                          }
                      }
                  }
                  else
                  {
                      addProperty(key, value);
                  }
              }
          }
      }
  
      /**
       * save properties to a file.
       * properties with multiple values are saved comma seperated.
       *
       * @param filename name of the properties file
       * @throws IOException
       */
      public void save(String filename)
          throws IOException
      {
          File file = new File(filename);
          PropertiesWriter out = new PropertiesWriter(file);
  
          out.writeComment("written by PropertiesConfiguration");
          out.writeComment(new Date().toString());
  
          for (Iterator i = this.getKeys(); i.hasNext(); )
          {
              String key = (String) i.next();
              String value = StringUtils.join(this.getStringArray(key), ", ");
              out.writeProperty(key, value);
          }
          out.flush();
          out.close();
      }
  
      /**
       * Gets the property value for including other properties files.
       * By default it is "include".
       *
       * @return A String.
       */
      public String getInclude()
      {
          return this.include;
      }
  
      /**
       * Sets the property value for including other properties files.
       * By default it is "include".
       *
       * @param inc A String.
       */
      public void setInclude(String inc)
      {
          this.include = inc;
      }
  
      /**
       * Controls whether additional files can be loaded by the include = <xxx>
       * statement or not. Base rule is, that objects created by the empty
       * C'tor can not have included files.
       *
       * @param boolean includesAllowed True if Includes are allowed.
       */
      protected void setIncludesAllowed(boolean includesAllowed)
      {
          this.includesAllowed = includesAllowed;
      }
  
      /**
       * Reports the status of file inclusion.
       *
       * @return True if include files are loaded.
       */
      public boolean getIncludesAllowed()
      {
          return this.includesAllowed;
      }
  
      /**
       * This class is used to read properties lines.  These lines do
       * not terminate with new-line chars but rather when there is no
       * backslash sign a the end of the line.  This is used to
       * concatenate multiple lines for readability.
       */
      class PropertiesReader
          extends LineNumberReader
      {
          /**
           * Constructor.
           *
           * @param reader A Reader.
           */
          public PropertiesReader(Reader reader)
          {
              super(reader);
          }
  
          /**
           * Read a property. Returns null if Stream is
           * at EOF. Concatenates lines ending with "\".
           * Skips lines beginning with "#" and empty lines.
           *
           * @return A string containing a property value or null
           *
           * @exception IOException
           */
          public String readProperty()
              throws IOException
          {
              StringBuffer buffer = new StringBuffer();
  
              while (true)
              {
                  String line = readLine();
                  if (line == null)
                  {
                      // EOF
                      return null;
                  }
  
                  line = line.trim();
  
                  if (StringUtils.isEmpty(line)
                      || (line.charAt(0) == '#'))
                  {
                      continue;
                  }
  
                  if (line.endsWith("\\"))
                  {
                      line = line.substring(0, line.length() - 1);
                      buffer.append(line);
                  }
                  else
                  {
                      buffer.append(line);
                      break;
                  }
              }
              return buffer.toString();
          }
      } // class PropertiesReader
  
      /**
       * This class is used to write properties lines.
       */
      class PropertiesWriter
          extends FileWriter
      {
          /**
           * Constructor.
           *
           * @param file the proerties file
           * @throws IOException
           */
          public PropertiesWriter(File file)
              throws IOException
          {
              super(file);
          }
  
          /**
           * Write a property.
           *
           * @param key
           * @param value
           * @exception IOException
           */
          public void writeProperty(String key, String value)
              throws IOException
          {
              write(key + " = " + value + "\n");
          }
  
          /**
           * Write a comment.
           *
           * @param comment
           * @exception IOException
           */
          public void writeComment(String comment)
              throws IOException
          {
              write("# " + comment + "\n");
          }
      } // class PropertiesWriter
  }
  
  
  

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