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/*

 * The JCS Conflation Suite (JCS) is a library of Java classes that

 * can be used to build automated or semi-automated conflation solutions.

 *

 * Copyright (C) 2003 Vivid Solutions

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * 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, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

 *

 * For more information, contact:

 *

 * Vivid Solutions

 * Suite #1A

 * 2328 Government Street

 * Victoria BC  V8T 5G5

 * Canada

 *

 * (250)385-6040

 * www.vividsolutions.com

 */

package com.vividsolutions.jcs.debug;

import java.io.*;

import java.util.*;

import java.lang.reflect.*;

/**

 * Provides routines to simplify and localize debugging output.

 * <p>

 * To enable the debugging functions, the Java system property <code>debug</code>

 * must be set to <code>on</code> in the java command line, using the following

 * option:

 * <pre>

 *     -Ddebug=on

 * </pre>

 *

 * @version 1.4

 */

public class Debug {

  private static String DEBUG_PROPERTY_NAME = "debug";

  private static String DEBUG_PROPERTY_VALUE_ON = "on";

  private static String DEBUG_PROPERTY_VALUE_TRUE = "true";

  private static boolean debugOn = false;

  static {

    String debugValue = System.getProperty(DEBUG_PROPERTY_NAME);

    if (debugValue != null) {

      if (debugValue.equalsIgnoreCase(DEBUG_PROPERTY_VALUE_ON)

          || debugValue.equalsIgnoreCase(DEBUG_PROPERTY_VALUE_TRUE) )

        debugOn = true;

    }

  }

  public static void main(String[] args)

  {

    Debug.println("Debugging is ON");

  }

  private static Debug debug = new Debug();

  private static final String DEBUG_LINE_TAG = "D! ";

  private PrintStream out;

  private Class[] printArgs;

  private Object watchObj = null;

  private Object[] args = new Object[1];

  public static boolean isDebugging() { return debugOn; }

  public static void print(String str) {

    if (!debugOn) return;

    debug.instancePrint(str);

  }

/*

  public static void println(String str) {

    if (! debugOn) return;

    debug.instancePrint(str);

    debug.println();

  }

*/

  public static void print(Object obj) {

    if (! debugOn) return;

    debug.instancePrint(obj);

  }

  public static void print(boolean isTrue, Object obj) {

    if (! debugOn) return;

    if (! isTrue) return;

    debug.instancePrint(obj);

  }

  public static void println(Object obj) {

    if (!debugOn) {

      return;

    }

    debug.instancePrint(obj);

    debug.println();

  }

  public static void addWatch(Object obj) {

    debug.instanceAddWatch(obj);

  }

  public static void printWatch() {

    debug.instancePrintWatch();

  }

  public static void printIfWatch(Object obj) {

    debug.instancePrintIfWatch(obj);

  }

  private Debug() {

    out = System.out;

    printArgs = new Class[1];

    try {

      printArgs[0] = Class.forName("java.io.PrintStream");

    }

    catch (Exception ex) {

      // ignore this exception - it will fail later anyway

    }

  }

  public void instancePrintWatch() {

    if (watchObj == null) return;

    instancePrint(watchObj);

  }

  public void instancePrintIfWatch(Object obj) {

    if (obj != watchObj) return;

    if (watchObj == null) return;

    instancePrint(watchObj);

  }

  public void instancePrint(Object obj)

  {

    if (obj instanceof Collection) {

      instancePrint(((Collection) obj).iterator());

    }

    else if (obj instanceof Iterator) {

      instancePrint((Iterator) obj);

    }

    else {

      instancePrintObject(obj);

    }

  }

  public void instancePrint(Iterator it)

  {

    for (; it.hasNext(); ) {

      Object obj = it.next();

      instancePrintObject(obj);

    }

  }

  public void instancePrintObject(Object obj) {

    //if (true) throw new RuntimeException("DEBUG TRAP!");

    Method printMethod = null;

    try {

      Class cls = obj.getClass();

      try {

        printMethod = cls.getMethod("print", printArgs);

        args[0] = out;

        out.print(DEBUG_LINE_TAG);

        printMethod.invoke(obj, args);

      }

      catch (NoSuchMethodException ex) {

        instancePrint(obj.toString());

      }

    }

    catch (Exception ex) {

      ex.printStackTrace(out);

    }

  }

  public void println() {

    out.println();

  }

  private void instanceAddWatch(Object obj) {

    watchObj = obj;

  }

  private void instancePrint(String str) {

    out.print(DEBUG_LINE_TAG);

    out.print(str);

  }

}