package org.apache.torque.engine.database.model;
   
   /*
    * 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.ArrayList;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.commons.collections.map.ListOrderedMap;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.torque.engine.EngineException;
  
  import org.xml.sax.Attributes;
  
  /**
   * Information about indices of a table.
   *
   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
   * @author <a href="mailto:dlr@finemaltcoding.com>Daniel Rall</a>
   * @author <a href="mailto:monroe@dukece.com>Greg Monroe</a>
   * @version $Id: Index.java,v 1.1 2007-10-21 07:57:27 abyrne Exp $
   */
  public class Index
  {
      /** Logging class from commons.logging */
      private static Log log = LogFactory.getLog(Index.class);
      /** name of the index */
      private String indexName;
      /** table */
      private Table parentTable;
      /** columns */
      private List indexColumns;
      /** The XML Options specified for this index */
      private Map options;
  
  
      /**
       * Creates a new instance with default characteristics (no name or
       * parent table, small column list size allocation, non-unique).
       */
      public Index()
      {
          indexColumns = new ArrayList(3);
          options = Collections.synchronizedMap(new ListOrderedMap());
      }
  
      /**
       * Creates a new instance for the list of columns composing an
       * index.  Otherwise performs as {@link #Index()}.
       *
       * @param table The table this index is associated with.
       * @param indexColumns The list of {@link
       * org.apache.torque.engine.database.model.Column} objects which
       * make up this index.  Cannot be empty.
       * @exception EngineException Error generating name.
       * @see #Index()
       */
      protected Index(Table table, List indexColumns)
          throws EngineException
      {
          this();
          setTable(table);
          if (!indexColumns.isEmpty())
          {
              this.indexColumns = indexColumns;
  
              if (log.isDebugEnabled())
              {
                  log.debug("Created Index named " + getName()
                          + " with " + indexColumns.size() + " columns");
              }
          }
          else
          {
              throw new EngineException("Cannot create a new Index using an "
                      + "empty list Column object");
          }
      }
 
     /**
      * Imports index from an XML specification
      *
      * @param attrib the xml attributes
      */
     public void loadFromXML(Attributes attrib)
     {
         indexName = attrib.getValue("name");
     }
 
     /**
      * Returns the uniqueness of this index.
      *
      * @return the uniqueness of this index
      */
     public boolean isUnique()
     {
         return false;
     }
 
     /**
      * Gets the name of this index.
      *
      * @return the name of this index
      */
     public String getName()
     {
         return indexName;
     }
 
     /**
      * Set the name of this index.
      *
      * @param name the name of this index
      */
     public void setName(String name)
     {
         this.indexName = name;
     }
 
     /**
      * Set the parent Table of the index
      *
      * @param parent the table
      */
     public void setTable(Table parent)
     {
         parentTable = parent;
     }
 
     /**
      * Get the parent Table of the index
      *
      * @return the table
      */
     public Table getTable()
     {
         return parentTable;
     }
 
     /**
      * Returns the Name of the table the index is in
      *
      * @return the name of the table
      */
     public String getTableName()
     {
         return parentTable.getName();
     }
 
     /**
      * Adds a new column to an index.
      *
      * @param attrib xml attributes for the column
      */
     public void addColumn(Attributes attrib)
     {
         indexColumns.add(attrib.getValue("name"));
     }
 
     /**
      * Return a comma delimited string of the columns which compose this index.
      *
      * @return a list of column names
      */
     public String getColumnList()
     {
         return Column.makeList(getColumns());
     }
 
     /**
      * Return the list of local columns. You should not edit this list.
      *
      * @return a list of columns
      */
     public List getColumns()
     {
         return indexColumns;
     }
 
     /**
      * Returns the list of names of the columns referenced by this
      * index.  Slightly over-allocates the list's buffer (just in case
      * more elements are going to be added, such as when a name is
      * being generated).  Feel free to modify this list.
      *
      * @return a list of column names
      */
     protected List getColumnNames()
     {
         List names = new ArrayList(indexColumns.size() + 2);
         Iterator i = getColumns().iterator();
         while (i.hasNext())
         {
             Column c = (Column) i.next();
             names.add(c.getName());
         }
         return names;
     }
 
     /**
      * String representation of the index. This is an xml representation.
      *
      * @return a xml representation
      */
     public String toString()
     {
         StringBuffer result = new StringBuffer();
         result.append(" <index name=\"")
               .append(getName())
               .append("\"");
 
         result.append(">\n");
 
         for (int i = 0; i < indexColumns.size(); i++)
         {
             result.append("  <index-column name=\"")
                 .append(indexColumns.get(i))
                 .append("\"/>\n");
         }
         result.append(" </index>\n");
         return result.toString();
     }
 
     /**
      * Add an XML Specified option key/value pair to this element's option set.
      *
      * @param key the key of the option.
      * @param value the value of the option.
      */
     public void addOption(String key, String value)
     {
         options.put(key, value);
     }
 
     /**
      * Get the value that was associated with this key in an XML option
      * element.
      *
      * @param key the key of the option.
      * @return The value for the key or a null.
      */
     public String getOption(String key)
     {
         return (String) options.get(key);
     }
 
     /**
      * Gets the full ordered hashtable array of items specified by XML option
      * statements under this element.<p>
      *
      * Note, this is not thread save but since it's only used for
      * generation which is single threaded, there should be minimum
      * danger using this in Velocity.
      *
      * @return An Map of all options. Will not be null but may be empty.
      */
     public Map getOptions()
     {
         return options;
     }
 }