simpleparameters.java

pastry的java实现的2.0b版

/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

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- Redistributions in binary form must reproduce the above copyright
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- Neither  the name  of Rice  University (RICE) nor  the names  of its
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This software is provided by RICE and the contributors on an "as is"
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********************************************************************************/
package rice.environment.params.simple;

import java.io.*;
import java.net.*;
import java.util.*;

import rice.environment.params.ParameterChangeListener;
import rice.environment.params.Parameters;

/**
 * This class represents a generic Java process launching program which reads in
 * preferences from a preferences file and then invokes another JVM using those
 * prefs. If the launched JVM dies, this process can be configured to restart
 * the JVM any number of times before giving up. This process can also be
 * configured to launch the second JVM with a specified memory allocation,
 * etc...
 *
 * @version $Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $
 * @author Alan Mislove
 */
public class SimpleParameters implements Parameters {

  private MyProperties properties;

  private MyProperties defaults;

  private Set changeListeners;

  /**
   * Where items are written out.
   */
  private String configFileName;

  private static String FILENAME_EXTENSION = ".params";

  private static String ARRAY_SPACER = ",";

  /**
   * @param orderedDefaults
   * @param mutableConfigFileName if this is null, no params are saved, if this
   *      file doesn't exist, you will get a warning printed to stdErr, then the
   *      file will be created if you ever store
   * @throws IOException
   */
  public SimpleParameters(String[] orderedDefaults, String mutableConfigFileName) {
    if (mutableConfigFileName != null) {
      this.configFileName = mutableConfigFileName + FILENAME_EXTENSION;
    }
    this.properties = new MyProperties();
    this.defaults = new MyProperties();
    this.changeListeners = new HashSet();

    for (int ctr = 0; ctr < orderedDefaults.length; ctr++) {
      try {
        ClassLoader loader = this.getClass().getClassLoader();
        // some VMs report the bootstrap classloader via null-return
        if (loader == null) {
          loader = ClassLoader.getSystemClassLoader();
        }
        this.defaults.load(loader.getResource(
          orderedDefaults[ctr] + FILENAME_EXTENSION).openStream());
      } catch (Exception ioe) {
        String errorString = "Warning, couldn't load param file:"
          + (orderedDefaults[ctr] + FILENAME_EXTENSION);
//        System.err.println(errorString);
//        ioe.printStackTrace(System.err);
        throw new ParamsNotPresentException(errorString, ioe);
      }
    }

    if (this.configFileName != null) {
      File f = new File(this.configFileName);
      if (f.exists()) {
        try {
          properties.load(new FileInputStream(this.configFileName));
        } catch (Exception e) {
          throw new ParamsNotPresentException("Error loading " + f, e);
        }
      } else {
        System.err.println("Configuration file " + f.getAbsolutePath()
          + " not present.  Using defaults.");
      }
    }
  }

  /**
   * Gets the Property attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The Property value
   */
  protected String getProperty(String name) {
    String result = properties.getProperty(name);

    if (result == null) {
      result = defaults.getProperty(name);
    }

    if (result == null) {
      System.err.println("WARNING: The parameter '" + name
        + "' was not found - this is likely going to cause an error.");
      //You " +
      //                     "can fix this by adding this parameter (and appropriate value) to the
      // proxy.params file in your ePOST " +
      //                     "directory.");
    } else {
      // remove any surrounding whitespace
      result = result.trim();
    }

    return result;
  }

  /**
   * Gets the Int attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The Int value
   */
  public int getInt(String name) {
    try {
      return Integer.parseInt(getProperty(name));
    } catch (NumberFormatException nfe) {
      throw new NumberFormatException(nfe.getMessage() + " for parameter "
        + name);
    }
  }

  /**
   * Gets the Double attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The Double value
   */
  public double getDouble(String name) {
    try {
      return Double.parseDouble(getProperty(name));
    } catch (NumberFormatException nfe) {
      throw new NumberFormatException(nfe.getMessage() + " for parameter "
        + name);
    }
  }

  /**
   * Gets the Float attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The Float value
   */
  public float getFloat(String name) {
    try {
      return Float.parseFloat(getProperty(name));
    } catch (NumberFormatException nfe) {
      throw new NumberFormatException(nfe.getMessage() + " for parameter "
        + name);
    }
  }

  /**
   * Gets the Long attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The Long value
   */
  public long getLong(String name) {
    try {
      return Long.parseLong(getProperty(name));
    } catch (NumberFormatException nfe) {
      throw new NumberFormatException(nfe.getMessage() + " for parameter "
        + name);
    }
  }

  /**
   * Gets the Boolean attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The Boolean value
   */
  public boolean getBoolean(String name) {
    return (new Boolean(getProperty(name))).booleanValue();
  }

  /**
   * Gets the InetAddress attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The InetAddress value
   * @exception UnknownHostException DESCRIBE THE EXCEPTION
   */
  public InetAddress getInetAddress(String name) throws UnknownHostException {
    return InetAddress.getByName(getString(name));
  }

  /**
   * Gets the InetSocketAddress attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The InetSocketAddress value
   * @exception UnknownHostException DESCRIBE THE EXCEPTION
   */
  public InetSocketAddress getInetSocketAddress(String name)
     throws UnknownHostException {
    return parseInetSocketAddress(getString(name));
  }

  /**
   * Gets the InetSocketAddressArray attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The InetSocketAddressArray value
   * @exception UnknownHostException DESCRIBE THE EXCEPTION
   */
  public InetSocketAddress[] getInetSocketAddressArray(String name)
     throws UnknownHostException {
    String[] addresses = getString(name).split(ARRAY_SPACER);
    List result = new LinkedList();

    for (int i = 0; i < addresses.length; i++) {
      InetSocketAddress address = parseInetSocketAddress(addresses[i]);

      if (address != null) {
        result.add(address);
      }
    }

    return (InetSocketAddress[]) result.toArray(new InetSocketAddress[0]);
  }

  /**
   * Gets the String attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The String value
   */
  public String getString(String name) {
    return getProperty(name);
  }

  /**
   * Gets the StringArray attribute of the SimpleParameters object
   *
   * @param name DESCRIBE THE PARAMETER
   * @return The StringArray value
   */
  public String[] getStringArray(String name) {
    String list = getProperty(name);

    if (list != null) {
      return (list.equals("") ? new String[0] : list.split(ARRAY_SPACER));
    } else {
      return null;
    }
  }