Class AbstractSearchTool

java.lang.Object
org.apache.velocity.tools.generic.SafeConfig
org.apache.velocity.tools.view.PagerTool
org.apache.velocity.tools.view.AbstractSearchTool
@DefaultKey("search") @InvalidScope({"application","session"}) public abstract class AbstractSearchTool extends PagerTool

Abstract view tool for doing "searching" and robust pagination of search results. The goal here is to provide a simple and uniform API for "search tools" that can be used in velocity templates (or even a standard Search.vm template). In particular, this class provides good support for result pagination and some very simple result caching.

Usage:
To use this class, you must extend it and implement the executeQuery(Object) method.

The setCriteria(Object) method takes an Object in order to allow the search criteria to meet your needs. Your criteria may be as simple as a single string, an array of strings, or whatever you like. The value passed into this method is that which will ultimately be passed into executeQuery(Object) to perform the search and return a list of results. A simple implementation might be like: 

protected List executeQuery(Object crit)
{
    return MyDbUtils.getFooBarsMatching((String)crit);
}

Here's an example of how your subclass would be used in a template: 

  <form name="search" method="get" action="$link.setRelative('search.vm')">
    <input type="text"name="find" value="$!search.criteria">
    <input type="submit" value="Find">
  </form>
  #if( $search.hasItems() )
  Showing $!search.pageDescription<br>
    #set( $i = $search.index )
    #foreach( $item in $search.page )
      ${i}. $!item <br>
      #set( $i = $i + 1 )
    #end
    <br>
    #if ( $search.pagesAvailable > 1 )
      #set( $pagelink = $link.setRelative('search.vm').addQueryData("find",$!search.criteria).addQueryData("show",$!search.itemsPerPage) )
      #if( $search.prevIndex )
          <a href="$pagelink.addQueryData('index',$!search.prevIndex)">Prev</a>
      #end
      #foreach( $index in $search.slip )
        #if( $index == $search.index )
          <b>$search.pageNumber</b>
        #else
          <a href="$pagelink.addQueryData('index',$!index)">$!search.getPageNumber($index)</a>
        #end
      #end
      #if( $search.nextIndex )
          <a href="$pagelink.addQueryData('index',$!search.nextIndex)">Next</a>
      #end
    #end
  #elseif( $search.criteria )
  Sorry, no matches were found for "$!search.criteria".
  #else
  Please enter a search term
  #end

The output of this might look like:

  <form method="get" action="">
   <input type="text" value="foo">
   <input type="submit" value="Find">
  </form>
  Showing 1-5 of 8<br>
  1. foo<br>
  2. bar<br>
  3. blah<br>
  4. woogie<br>
  5. baz<br><br>
  <b>1</b> <a href="">2</a> <a href="">Next</a>

Example tools.xml configuration:

<tools>
  <toolbox scope="request">
    <tool class="com.foo.tools.MySearchTool"/>
  </toolbox>
</tools>
Since:
VelocityTools 2.0
Version:
$Revision$ $Date$
Author:
Nathan Bubna

  • Field Details

    • DEFAULT_CRITERIA_KEY

      public static final String DEFAULT_CRITERIA_KEY
      See Also:

    • STORED_RESULTS_KEY

      protected static final String STORED_RESULTS_KEY
      the key under which StoredResults are kept in session

  • Constructor Details

    • AbstractSearchTool

      public AbstractSearchTool()

  • Method Details

    • setup

      public void setup(javax.servlet.http.HttpServletRequest request)
      Sets the criteria *if* it is set in the request parameters.
      Overrides:
      setup in class PagerTool
      Parameters:
      request - the current HttpServletRequest

    • setCriteriaKey

      public void setCriteriaKey(String key)

    • getCriteriaKey

      public String getCriteriaKey()

    • reset

      public void reset()
      Sets the criteria and results to null, page index to zero, and items per page to the default.
      Overrides:
      reset in class PagerTool

    • setCriteria

      public void setCriteria(Object criteria)
      Sets the criteria for this search.
      Parameters:
      criteria - - the criteria used for this search

    • getCriteria

      public Object getCriteria()
      Return the criteria object for this request. (for a simple search mechanism, this will typically be just a java.lang.String)
      Returns:
      criteria object

    • getItems

      public List getItems()
      Gets the results for the given criteria either in memory or by performing a new query for them. If the criteria is null, an empty list will be returned.
      Overrides:
      getItems in class PagerTool
      Returns:
      List of all items for the criteria

    • getStoredItems

      protected List getStoredItems()
      Description copied from class: PagerTool
      Retrieves stored search items (if any) from the user's session attributes.
      Overrides:
      getStoredItems in class PagerTool
      Returns:
      the List retrieved from memory

    • setStoredItems

      protected void setStoredItems(List items)
      Description copied from class: PagerTool
      Stores current search items in the user's session attributes (if one currently exists) in order to do efficient result pagination.

      Override this to store search items somewhere besides the HttpSession or to prevent storage of items across requests. In the former situation, you must also override getStoredItems().

      Overrides:
      setStoredItems in class PagerTool
      Parameters:
      items - the List to be stored

    • executeQuery

      protected abstract List executeQuery(Object criteria)
      Executes a query for the specified criteria.

      This method must be implemented! A simple implementation might be something like:

      protected List executeQuery(Object crit)
{
    return MyDbUtils.getFooBarsMatching((String)crit);
}
      Parameters:
      criteria - search criteria
      Returns:
      a List of results for this query

    • getStoredResults

      protected AbstractSearchTool.StoredResults getStoredResults()
      Retrieves stored search results (if any) from the user's session attributes.
      Returns:
      the AbstractSearchTool.StoredResults retrieved from memory

    • setStoredResults

      protected void setStoredResults(AbstractSearchTool.StoredResults results)
      Stores current search results in the user's session attributes (if one currently exists) in order to do efficient result pagination.

      Override this to store search results somewhere besides the HttpSession or to prevent storage of results across requests. In the former situation, you must also override getStoredResults().

      Parameters:
      results - the AbstractSearchTool.StoredResults to be stored