package org.apache.maven.doxia.sink.impl;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.util.Enumeration;
  import java.util.Arrays;
  
  import javax.swing.text.AttributeSet;
  import javax.swing.text.MutableAttributeSet;
  
  import org.apache.maven.doxia.markup.Markup;
  import org.apache.maven.doxia.sink.SinkEventAttributes;
  
  /**
   * Collection of common utility methods for sinks.
   *
   * @author ltheussl
   * @version $Id: SinkUtils.html 979316 2016-02-02 21:51:43Z hboutemy $
   * @since 1.1
   */
  public class SinkUtils
  {
  
      /** Do not instantiate. */
      private SinkUtils()
      {
          // Utility class
      }
  
      /**
       * The set of base attributes.
       */
      public static final String[] SINK_BASE_ATTRIBUTES =
      {
          SinkEventAttributes.CLASS, SinkEventAttributes.ID, SinkEventAttributes.LANG,
          SinkEventAttributes.STYLE, SinkEventAttributes.TITLE
      };
  
      /**
       * The attributes that are supported for the br tag.
       */
      public static final String[] SINK_BR_ATTRIBUTES =
      {
          SinkEventAttributes.CLASS, SinkEventAttributes.ID,
          SinkEventAttributes.STYLE, SinkEventAttributes.TITLE
      };
  
      /**
       * The attributes that are supported for the <img> tag.
       */
      public static final String[] SINK_IMG_ATTRIBUTES;
  
      /**
       * The attributes that are supported for the section tags, like <p>, <h2>, <div>.
       */
      public static final String[] SINK_SECTION_ATTRIBUTES;
  
      /**
       * The attributes that are supported for the <div> and <pre> tags.
       */
      public static final String[] SINK_VERBATIM_ATTRIBUTES;
  
      /**
       * The attributes that are supported for the <hr> tag.
       */
      public static final String[] SINK_HR_ATTRIBUTES;
  
      /**
       * The attributes that are supported for the <a> tag.
       */
      public static final String[] SINK_LINK_ATTRIBUTES;
  
      /**
       * The attributes that are supported for the <table> tag.
       */
      public static final String[] SINK_TABLE_ATTRIBUTES;
  
      /**
       * The attributes that are supported for the <td> and <th> tags.
       */
      public static final String[] SINK_TD_ATTRIBUTES;
  
     /**
      * The attributes that are supported for the <tr> tag.
      */
     public static final String[] SINK_TR_ATTRIBUTES;
 
     private static final String[] IMG_ATTRIBUTES =
     {
         SinkEventAttributes.ALIGN, SinkEventAttributes.ALT, SinkEventAttributes.BORDER,
         SinkEventAttributes.HEIGHT, SinkEventAttributes.HSPACE, SinkEventAttributes.ISMAP,
         SinkEventAttributes.SRC, SinkEventAttributes.USEMAP, SinkEventAttributes.VSPACE,
         SinkEventAttributes.WIDTH
     };
 
     private static final String[] HR_ATTRIBUTES =
     {
         SinkEventAttributes.ALIGN, SinkEventAttributes.NOSHADE, SinkEventAttributes.SIZE,
         SinkEventAttributes.WIDTH
     };
 
     private static final String[] LINK_ATTRIBUTES =
     {
         SinkEventAttributes.CHARSET, SinkEventAttributes.COORDS, SinkEventAttributes.HREF,
         SinkEventAttributes.HREFLANG, SinkEventAttributes.REL, SinkEventAttributes.REV,
         SinkEventAttributes.SHAPE, SinkEventAttributes.TARGET, SinkEventAttributes.TYPE
     };
 
     private static final String[] TABLE_ATTRIBUTES =
     {
         SinkEventAttributes.ALIGN, SinkEventAttributes.BGCOLOR, SinkEventAttributes.BORDER,
         SinkEventAttributes.CELLPADDING, SinkEventAttributes.CELLSPACING, SinkEventAttributes.FRAME,
         SinkEventAttributes.RULES, SinkEventAttributes.SUMMARY, SinkEventAttributes.WIDTH
     };
 
     private static final String[] TABLE_CELL_ATTRIBUTES =
     {
         SinkEventAttributes.ABBRV, SinkEventAttributes.ALIGN, SinkEventAttributes.AXIS,
         SinkEventAttributes.BGCOLOR, SinkEventAttributes.COLSPAN, SinkEventAttributes.HEADERS,
         SinkEventAttributes.HEIGHT, SinkEventAttributes.NOWRAP, SinkEventAttributes.ROWSPAN,
         SinkEventAttributes.SCOPE, SinkEventAttributes.VALIGN, SinkEventAttributes.WIDTH
     };
 
     static
     {
         SINK_IMG_ATTRIBUTES = join( SINK_BASE_ATTRIBUTES, IMG_ATTRIBUTES );
         SINK_SECTION_ATTRIBUTES =
                 join( SINK_BASE_ATTRIBUTES, new String[] {SinkEventAttributes.ALIGN} );
         SINK_VERBATIM_ATTRIBUTES =
                 join( SINK_BASE_ATTRIBUTES,
                 new String[] {SinkEventAttributes.ALIGN, SinkEventAttributes.DECORATION, SinkEventAttributes.WIDTH} );
         SINK_HR_ATTRIBUTES = join( SINK_BASE_ATTRIBUTES, HR_ATTRIBUTES );
         SINK_LINK_ATTRIBUTES = join( SINK_BASE_ATTRIBUTES, LINK_ATTRIBUTES );
         SINK_TABLE_ATTRIBUTES = join( SINK_BASE_ATTRIBUTES, TABLE_ATTRIBUTES );
         SINK_TR_ATTRIBUTES =
                 join( SINK_BASE_ATTRIBUTES,
                 new String[] {SinkEventAttributes.ALIGN, SinkEventAttributes.BGCOLOR, SinkEventAttributes.VALIGN} );
         SINK_TD_ATTRIBUTES = join( SINK_BASE_ATTRIBUTES, TABLE_CELL_ATTRIBUTES );
     }
 
     private static String[] join( String[] a, String[] b )
     {
         String[] temp = new String[a.length + b.length];
         System.arraycopy( a, 0, temp, 0, a.length );
         System.arraycopy( b, 0, temp, a.length, b.length );
 
         Arrays.sort( temp ); // necessary for binary searches in filterAttributes()
 
         return temp;
     }
 
     /**
      * Utility method to get an AttributeSet as a String.
      * The resulting String is in the form ' name1="value1" name2="value2" ...',
      * ie it can be appended directly to an xml start tag. Attribute values that are itself
      * AttributeSets are ignored unless the Attribute name is SinkEventAttributeSet.STYLE,
      * in which case they are written as outlined at
      * {@link org.apache.maven.doxia.sink.SinkEventAttributes#STYLE SinkEventAttributes.STYLE}.
      * All other keys and values are written as Strings.
      *
      * @param att The AttributeSet. May be null, in which case an empty String is returned.
      * @return the AttributeSet as a String in a form that can be appended to an xml start tag.
      */
     public static String getAttributeString( AttributeSet att )
     {
         if ( att == null )
         {
             return "";
         }
 
         StringBuilder sb = new StringBuilder();
 
         Enumeration<?> names = att.getAttributeNames();
 
         while ( names.hasMoreElements() )
         {
             Object key = names.nextElement();
             Object value = att.getAttribute( key );
 
             if ( value instanceof AttributeSet )
             {
                 // Other AttributeSets are ignored
                 if ( SinkEventAttributes.STYLE.equals( key.toString() ) )
                 {
                     sb.append( Markup.SPACE ).append( key.toString() ).append( Markup.EQUAL )
                         .append( Markup.QUOTE ).append( asCssString( (AttributeSet) value ) )
                         .append( Markup.QUOTE );
                 }
             }
             else
             {
                 sb.append( Markup.SPACE ).append( key.toString() ).append( Markup.EQUAL )
                     .append( Markup.QUOTE ).append( value.toString() ).append( Markup.QUOTE );
             }
         }
 
         return sb.toString();
     }
 
     private static String asCssString( AttributeSet att )
     {
         StringBuilder sb = new StringBuilder();
 
         Enumeration<?> names = att.getAttributeNames();
 
         while ( names.hasMoreElements() )
         {
             Object key = names.nextElement();
             Object value = att.getAttribute( key );
 
             // don't go recursive
             if ( !( value instanceof AttributeSet ) )
             {
                 sb.append( key.toString() ).append( Markup.COLON )
                     .append( Markup.SPACE ).append( value.toString() );
 
                 if ( names.hasMoreElements() )
                 {
                     sb.append( Markup.SEMICOLON ).append( Markup.SPACE );
                 }
             }
         }
 
         return sb.toString();
     }
 
     /**
      * Filters the given AttributeSet.
      * Removes all attributes whose name (key) is not contained in the sorted array valids.
      *
      * @param attributes The AttributeSet to filter. The String values of Attribute names
      * are compared to the elements of the valids array.
      * @param valids a sorted array of attribute names that are to be kept in the resulting AttributeSet.
      *      <b>Note:</b> a binary search is employed, so the array has to be sorted for correct results.
      * @return A filtered MutableAttributeSet object. Returns null if the input AttributeSet is null.
      *      If the array of valids is either null or empty, an empty AttributeSet is returned.
      */
     public static MutableAttributeSet filterAttributes( AttributeSet attributes, String[] valids )
     {
         if ( attributes == null )
         {
             return null;
         }
 
         if ( valids == null || valids.length == 0 )
         {
             return new SinkEventAttributeSet( 0 );
         }
 
         MutableAttributeSet atts = new SinkEventAttributeSet( attributes.getAttributeCount() );
 
         Enumeration<?> names = attributes.getAttributeNames();
 
         while ( names.hasMoreElements() )
         {
             String key = names.nextElement().toString();
 
             if ( Arrays.binarySearch( valids, key ) >= 0 )
             {
                 atts.addAttribute( key, attributes.getAttribute( key ) );
             }
         }
 
         return atts;
     }
 }