cvs commit: jakarta-velocity/src/java/org/apache/velocity/util/tools VelocityFormatter.java

[da...@locus.apache.org]

daveb       00/10/31 19:33:22

  Added:       src/java/org/apache/velocity/util/tools
                        VelocityFormatter.java
  Log:
  Initial add of a context tool. This will be demoed in the Forum example.
  
  Revision  Changes    Path
  1.1                  jakarta-velocity/src/java/org/apache/velocity/util/tools/VelocityFormatter.java
  
  Index: VelocityFormatter.java
  ===================================================================
  package org.apache.velocity.util.tools;
  
  /*
   * Copyright (c) 1997-2000 The Java Apache Project.  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. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the Java Apache
   *    Project for use in the Apache JServ servlet engine project
   *    <http://java.apache.org/>."
   *
   * 4. The names "Apache JServ", "Apache JServ Servlet Engine", "Turbine",
   *    "Apache Turbine", "Turbine Project", "Apache Turbine Project" and
   *    "Java Apache Project" must not be used to endorse or promote products
   *    derived from this software without prior written permission.
   *
   * 5. Products derived from this software may not be called "Apache JServ"
   *    nor may "Apache" nor "Apache JServ" appear in their names without
   *    prior written permission of the Java Apache Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the Java Apache
   *    Project for use in the Apache JServ servlet engine project
   *    <http://java.apache.org/>."
   *
   * THIS SOFTWARE IS PROVIDED BY THE JAVA APACHE PROJECT "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 JAVA APACHE PROJECT 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 Java Apache Group. For more information
   * on the Java Apache Project and the Apache JServ Servlet Engine project,
   * please see <http://java.apache.org/>.
   *
   */
  
  // Java Core Classes
  import java.util.*;
  import java.text.*;
  import java.lang.reflect.Array;
  
  // Veclocity classes
  import org.apache.velocity.*;
  
  /**
   * Formatting tool for inserting into the Velocity WebContext.  Can
   * format dates or lists of objects.
   *
   * <p>Here's an example of some uses:
   *
   * <code><pre>
   * $formatter.formatShortDate($object.Date)
   * $formatter.formatLongDate($db.getRecord(232).getDate())
   * $formatter.formatArray($array)
   * $formatter.limitLen(30, $object.Description)
   * </pre></code>
   * 
   * @author <a href="sean@somacity.com">Sean Legassick</a>
   * @version $Id: VelocityFormatter.java,v 1.1 2000/11/01 03:33:21 daveb Exp $
   */
  public class VelocityFormatter
  {
      Context context = null;
      NumberFormat nf = NumberFormat.getInstance();
  
      /**
       * Constructor needs a backpointer to the context.
       *
       * @param context A Context.
       */
      public VelocityFormatter(Context context)
      {
          this.context = context;
      }
  
      /**
       * Formats a date in 'short' style.
       *
       * @param date A Date.
       * @return A String.
       */
      public String formatShortDate(Date date)
      {
          return DateFormat
              .getDateInstance(DateFormat.SHORT).format(date);
      }
  
      /**
       * Formats a date in 'long' style.
       *
       * @param date A Date.
       * @return A String.
       */
      public String formatLongDate(Date date)
      {
          return DateFormat
              .getDateInstance(DateFormat.LONG).format(date);
      }
  
      /**
       * Formats a date/time in 'short' style.
       *
       * @param date A Date.
       * @return A String.
       */
      public String formatShortDateTime(Date date)
      {
          return DateFormat
              .getDateTimeInstance(DateFormat.SHORT,
                                   DateFormat.SHORT).format(date);
      }
  
      /**
       * Formats a date/time in 'long' style.
       *
       * @param date A Date.
       * @return A String.
       */
      public String formatLongDateTime(Date date)
      {
          return DateFormat.getDateTimeInstance(
                  DateFormat.LONG, DateFormat.LONG).format(date);
      }
  
      /**
       * Formats an array into the form "A, B and C".
       *
       * @param array An Object.
       * @return A String.
       */
      public String formatArray(Object array)
      {
          return formatArray(array, ", ", " and ");
      }
  
      /**
       * Formats an array into the form
       * "A&lt;delim&gt;B&lt;delim&gt;C".
       *
       * @param array An Object.
       * @param delim A String.
       * @return A String.
       */
      public String formatArray(Object array,
                                String delim)
      {
          return formatArray(array, delim, delim);
      }
  
      /**
       * Formats an array into the form
       * "A&lt;delim&gt;B&lt;finaldelim&gt;C".
       *
       * @param array An Object.
       * @param delim A String.
       * @param finalDelim A String.
       * @return A String.
       */
      public String formatArray(Object array,
                                String delim,
                                String finaldelim)
      {
          StringBuffer sb = new StringBuffer();
          int arrayLen = Array.getLength(array);
          for (int i = 0; i < arrayLen; i++)
          {
              // Use the Array.get method as this will automatically
              // wrap primitive types in a suitable Object-derived
              // wrapper if necessary.
              sb.append(Array.get(array, i).toString());
              if (i  < arrayLen - 2)
              {
                  sb.append(delim);
              }
              else if (i < arrayLen - 1)
              {
                  sb.append(finaldelim);
              }
          }
          return sb.toString();
      }
  
      /**
       * Formats a vector into the form "A, B and C".
       *
       * @param vector A Vector.
       * @return A String.
       */
      public String formatVector(Vector vector)
      {
          return formatVector(vector, ", ", " and ");
      }
  
      /**
       * Formats a vector into the form "A&lt;delim&gt;B&lt;delim&gt;C".
       *
       * @param vector A Vector.
       * @param delim A String.
       * @return A String.
       */
      public String formatVector(Vector vector,
                                 String delim)
      {
          return formatVector(vector, delim, delim);
      }
  
      /**
       * Formats a vector into the form
       * "Adelim&gt;B&lt;finaldelim&gt;C".
       *
       * @param vector A Vector.
       * @param delim A String.
       * @param finalDelim A String.
       * @return A String.
       */
      public String formatVector(Vector vector,
                                 String delim,
                                 String finaldelim)
      {
          StringBuffer sb = new StringBuffer();
          for (int i = 0; i < vector.size(); i++)
          {
              sb.append(vector.elementAt(i).toString());
              if (i < vector.size() - 2)
              {
                  sb.append(delim);
              }
              else if (i < vector.size() - 1)
              {
                  sb.append(finaldelim);
              }
          }
          return sb.toString();
      }
  
      /**
       * Limits 'string' to 'maxlen' characters.  If the string gets
       * curtailed, "..." is appended to it.
       *
       * @param maxlen An int with the maximum length.
       * @param string A String.
       * @return A String.
       */
      public String limitLen(int maxlen,
                             String string)
      {
          return limitLen(maxlen, string, "...");
      }
  
      /**
       * Limits 'string' to 'maxlen' character.  If the string gets
       * curtailed, 'suffix' is appended to it.
       *
       * @param maxlen An int with the maximum length.
       * @param string A String.
       * @param suffix A String.
       * @return A String.
       */
      public String limitLen(int maxlen,
                             String string,
                             String suffix)
      {
          String ret = string;
          if (string.length() > maxlen)
          {
              ret = string.substring(0, maxlen - suffix.length()) + suffix;
          }
          return ret;
      }
  
      /**
       * Class that returns alternating values in a template.  It stores
       * a list of alternate Strings, whenever alternate() is called it
       * switches to the next in the list.  The current alternate is
       * retrieved through toString() - i.e. just by referencing the
       * object in a Velocity template.  For an example of usage see the
       * makeAlternator() method below.
       */
      public class VelocityAlternator
      {
          String[] alternates = null;
          int current = 0;
  
          /**
           * Constructor takes an array of Strings.
           *
           * @param alternates A String[].
           */
          public VelocityAlternator(String[] alternates)
          {
              this.alternates = alternates;
          }
  
          /**
           * Alternates to the next in the list.
           *
           * @return A String.
           */
          public String alternate()
          {
              current++;
              current %= alternates.length;
              return "";
          }
  
          /**
           * Returns the current alternate.
           *
           * @return A String.
           */
          public String toString()
          {
              return alternates[current];
          }
      }
  
      /**
       * Makes an alternator object that alternates between two values.
       *
       * <p>Example usage in a Velocity template:
       *
       * <code><pre>
       * &lt;table&gt;
       * $formatter.makeAlternator(rowcolor, "#c0c0c0", "#e0e0e0")
       * #foreach $item in $items
       * #begin
       * &lt;tr&gt;&lt;td bgcolor="$rowcolor"&gt;$item.Name&lt;/td&gt;&lt;/tr&gt;
       * $rowcolor.alternate()
       * #end
       * &lt;/table&gt;
       * </pre></code>
       *
       * @param name A String.
       * @param alt1 A String.
       * @param alt2 A String.
       * @return A String.
       */
      public String makeAlternator(String name,
                                   String alt1,
                                   String alt2)
      {
          String[] alternates = { alt1, alt2 };
          context.put(name, new VelocityAlternator(alternates));
          return "";
      }
  
      /**
       * Makes an alternator object that alternates between three
       * values.
       *
       * @param name A String.
       * @param alt1 A String.
       * @param alt2 A String.
       * @param alt3 A String.
       * @return A String.
       */
      public String makeAlternator(String name,
                                   String alt1,
                                   String alt2,
                                   String alt3)
      {
          String[] alternates = { alt1, alt2, alt3 };
          context.put(name, new VelocityAlternator(alternates));
          return "";
      }
  
      /**
       * Makes an alternator object that alternates between four values.
       *
       * @param name A String.
       * @param alt1 A String.
       * @param alt2 A String.
       * @param alt3 A String.
       * @param alt4 A String.
       * @return A String.
       */
      String makeAlternator(String name,
                            String alt1,
                            String alt2,
                            String alt3,
                            String alt4)
      {
          String[] alternates = { alt1, alt2, alt3, alt4 };
          context.put(name, new VelocityAlternator(alternates));
          return "";
      }
  
      /**
       * Returns a default value if the object passed is null.
       */
      public Object isNull(Object o, Object dflt)
      {
          if ( o == null )
          {
              return dflt;
          }
          else
          {
              return o;
          }
      }
  }