nbubna 2004/11/10 19:46:44
Modified: src/java/org/apache/velocity/tools/view/tools
AbstractSearchTool.java
Log:
factor out basic paging functionality into new AbstractPagerTool
Revision Changes Path
1.8 +40 -367
jakarta-velocity-tools/src/java/org/apache/velocity/tools/view/tools/AbstractSearchTool.java
Index: AbstractSearchTool.java
===================================================================
RCS file:
/home/cvs/jakarta-velocity-tools/src/java/org/apache/velocity/tools/view/tools/AbstractSearchTool.java,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -r1.7 -r1.8
--- AbstractSearchTool.java 12 Mar 2004 20:30:32 -0000 1.7
+++ AbstractSearchTool.java 11 Nov 2004 03:46:44 -0000 1.8
@@ -1,5 +1,5 @@
/*
- * Copyright 2003 The Apache Software Foundation.
+ * Copyright 2003-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -79,28 +79,28 @@
* <input type="text"name="find" value="$!search.criteria">
* <input type="submit" value="Find">
* </form>
- * #if( $search.hasResults() )
+ * #if( $search.hasItems() )
* Showing $!search.pageDescription<br>
* #set( $i = $search.index )
- * #foreach( $result in $search.page )
- * ${i}. $!result <br>
+ * #foreach( $item in $search.page )
+ * ${i}. $!item <br>
* #set( $i = $i + 1 )
* #end
* <br>
* #if ( $search.pagesAvailable > 1 )
- * #set( $searchlink =
$link.setRelative('search.vm').addQueryData("find",$!search.criteria).addQueryData("show",$!search.itemsPerPage)
)
+ * #set( $pagelink =
$link.setRelative('search.vm').addQueryData("find",$!search.criteria).addQueryData("show",$!search.itemsPerPage)
)
* #if( $search.prevIndex )
- * <a
href="$searchlink.addQueryData('index',$!search.prevIndex)">Prev</a>
+ * <a
href="$pagelink.addQueryData('index',$!search.prevIndex)">Prev</a>
* #end
* #foreach( $index in $search.slip )
* #if( $index == $search.index )
* <b>$search.pageNumber</b>
* #else
- * <a
href="$searchlink.addQueryData('index',$!index)">$!search.getPageNumber($index)</a>
+ * <a
href="$pagelink.addQueryData('index',$!index)">$!search.getPageNumber($index)</a>
* #end
* #end
* #if( $search.nextIndex )
- * <a
href="$searchlink.addQueryData('index',$!search.nextIndex)">Next</a>
+ * <a
href="$pagelink.addQueryData('index',$!search.nextIndex)">Next</a>
* #end
* #end
* #elseif( $search.criteria )
@@ -128,7 +128,7 @@
* <pre><tool>
* <key>search</key>
* <scope>request</scope>
- * <class>com.foo.tools.MyAbstractSearchTool</class>
+ * <class>com.foo.tools.MySearchTool</class>
* </tool>
* </pre>
* </p>
@@ -137,146 +137,41 @@
* @since VelocityTools 1.0
* @version $Revision$ $Date$
*/
-public abstract class AbstractSearchTool implements ViewTool
+public abstract class AbstractSearchTool extends AbstractPagerTool
{
-
-
- /** the default number of results shown per page */
- public static final int DEFAULT_ITEMS_PER_PAGE = 10;
-
- /** the default max number of result page indices to list */
- public static final int DEFAULT_SLIP_SIZE = 20;
-
/** the key under which StoredResults are kept in session */
protected static final String STORED_RESULTS_KEY =
StoredResults.class.getName();
- private List results;
private Object criteria;
- private int index = 0;
- private int slipSize = DEFAULT_SLIP_SIZE;
- private int itemsPerPage = DEFAULT_ITEMS_PER_PAGE;
-
- protected HttpSession session;
-
-
- /**
- * Initializes this instance by grabbing the request
- * and session objects from the current ViewContext.
- *
- * @param obj the current ViewContext
- * @throws ClassCastException if the param is not a ViewContext
- */
- public void init(Object obj)
- {
- ViewContext context = (ViewContext)obj;
- HttpServletRequest request = context.getRequest();
- session = request.getSession(false);
- setup(request);
- }
-
-
- /**
- * Abstract method to make it as obvious as possible just
- * where implementing classes should be retrieving and configuring
- * search/display parameters.
- * <p>A simple implementation would be:
- * <pre>
- * public void setup(HttpServletRequest req)
- * {
- * ParameterParser pp = new ParameterParser(req);
- * setCriteria(pp.getString("find"));
- * setIndex(pp.getInt("index", 0));
- * setItemsPerPage(pp.getInt("show", DEFAULT_ITEMS_PER_PAGE));
- * }
- * </pre>
- *
- * @param request the current HttpServletRequest
- */
- public abstract void setup(HttpServletRequest request);
/* ---------------------- mutators ----------------------------- */
-
/**
* Sets the criteria and results to null, page index to zero, and
* items per page to the default.
*/
public void reset()
{
- results = null;
+ super.reset();
criteria = null;
- index = 0;
- itemsPerPage = DEFAULT_ITEMS_PER_PAGE;
}
/**
- * Sets the criteria for this search and clears existing results.
+ * Sets the criteria for this search.
*
* @param criteria - the criteria used for this search
*/
public void setCriteria(Object criteria)
{
this.criteria = criteria;
- this.results = null;
- }
-
-
- /**
- * Sets the index of the first result in the current page
- *
- * @param index the result index to start the current page with
- */
- public void setIndex(int index)
- {
- if (index < 0)
- {
- /* quietly override to a reasonable value */
- index = 0;
- }
- this.index = index;
- }
-
-
- /**
- * Sets the number of items returned in a page of results
- *
- * @param itemsPerPage the number of items to be returned per page
- */
- public void setItemsPerPage(int itemsPerPage)
- {
- if (itemsPerPage < 1)
- {
- /* quietly override to a reasonable value */
- itemsPerPage = DEFAULT_ITEMS_PER_PAGE;
- }
- this.itemsPerPage = itemsPerPage;
- }
-
-
- /**
- * Sets the number of result page indices for [EMAIL PROTECTED]
#getSlip} to list.
- * (for google-ish result page links).
- *
- * @see #getSlip
- * @param slipSize - the number of result page indices to list
- */
- public void setSlipSize(int slipSize)
- {
- if (slipSize < 2)
- {
- /* quietly override to a reasonable value */
- slipSize = DEFAULT_SLIP_SIZE;
- }
- this.slipSize = slipSize;
}
/* ---------------------- accessors ----------------------------- */
-
/**
* Return the criteria object for this request.
* (for a simple search mechanism, this will typically be
@@ -291,272 +186,58 @@
/**
- * Return the set number of items to be displayed per page of results
- *
- * @return current number of results shown per page
- */
- public int getItemsPerPage()
- {
- return itemsPerPage;
- }
-
-
- /**
- * Returns the number of result page indices [EMAIL PROTECTED] #getSlip}
- * will return per request (if available).
- *
- * @return the number of result page indices [EMAIL PROTECTED] #getSlip}
- * will try to return
- */
- public int getSlipSize()
- {
- return slipSize;
- }
-
-
- /**
- * Return the current search result index.
- *
- * @return the index for the beginning of the current page
- */
- public int getIndex()
- {
- return index;
- }
-
-
- /**
- * Checks whether or not the result list is empty.
- *
- * @return <code>true</code> if the result list is not empty.
+ * @deprecated Use [EMAIL PROTECTED] AbstractPagerTool#hasItems()}
*/
public boolean hasResults()
{
- return !getResults().isEmpty();
+ return hasItems();
}
/**
- * Return the results for the given criteria. This is guaranteed
- * to never return <code>null</code>.
- *
- * @return [EMAIL PROTECTED] List} of all results for the criteria
+ * @deprecated Use [EMAIL PROTECTED] AbstractPagerTool#getItems()}.
*/
public List getResults()
{
- if (results == null)
- {
- results = retrieveResults();
- }
- return results;
- }
-
-
- /**
- * Return the index for the next page of results
- * (as determined by the current index, items per page, and
- * the number of results). If no "next page" exists, then null is
- * returned.
- *
- * @return index for the next page or <code>null</code> if none exists
- */
- public Integer getNextIndex()
- {
- int next = index + itemsPerPage;
- if (next < getResults().size())
- {
- return new Integer(next);
- }
- return null;
- }
-
-
- /**
- * Return the index for the previous page of results
- * (as determined by the current index, items per page, and
- * the number of results). If no "next page" exists, then null is
- * returned.
- *
- * @return index for the previous page or <code>null</code> if none
exists
- */
- public Integer getPrevIndex()
- {
- int prev = Math.min(index, getResults().size()) - itemsPerPage;
- if (index > 0)
- {
- return new Integer(Math.max(0, prev));
- }
- return null;
- }
-
-
- /**
- * Return the number of pages that can be made from this list
- * given the set number of items per page.
- */
- public int getPagesAvailable()
- {
- return (int)Math.ceil(getResults().size() / (double)itemsPerPage);
- }
-
-
- /**
- * Return the current "page" of search results.
- *
- * @return a [EMAIL PROTECTED] List} of results for the "current page"
- */
- public List getPage()
- {
- /* return null if we have no results */
- if (!hasResults())
- {
- return null;
- }
- /* quietly keep the page indices to legal values for robustness'
sake */
- int start = Math.min(getResults().size() - 1, index);
- int end = Math.min(getResults().size(), index + itemsPerPage);
- return getResults().subList(start, end);
- }
-
-
- /**
- * Returns the "page number" for the specified index. Because the page
- * number is used for the user interface, the page numbers are 1-based.
- *
- * @param i the index that you want the page number for
- * @return the approximate "page number" for the specified index or
- * <code>null</code> if there are no results
- */
- public Integer getPageNumber(int i)
- {
- if (!hasResults())
- {
- return null;
- }
- return new Integer(1 + i / itemsPerPage);
- }
-
-
- /**
- * Returns the "page number" for the current index. Because the page
- * number is used for the user interface, the page numbers are 1-based.
- *
- * @return the approximate "page number" for the current index or
- * <code>null</code> if there are no results
- */
- public Integer getPageNumber()
- {
- return getPageNumber(index);
+ return getItems();
}
/**
- * <p>Returns a description of the current page. This implementation
- * displays a 1-based range of result indices and the total number
- * of results. (e.g. "1 - 10 of 42" or "7 of 7")</p>
- *
- * <p>Sub-classes may override this to provide a customized
- * description (such as one in another language).</p>
- *
- * @return a description of the current page
- */
- public String getPageDescription()
- {
- StringBuffer out = new StringBuffer();
- int first = index + 1;
- int total = getResults().size();
- if (first >= total)
- {
- out.append(total);
- out.append(" of ");
- out.append(total);
- }
- else
- {
- int last = Math.min(index + itemsPerPage, total);
- out.append(first);
- out.append(" - ");
- out.append(last);
- out.append(" of ");
- out.append(total);
- }
- return out.toString();
- }
-
-
- /**
- * Return a <b>S</b>liding <b>L</b>ist of <b>I</b>ndices for <b>P</b>ages
- * of search results.
- *
- * <p>Essentially, this returns a list of result indices that correspond
- * to available pages of search results (as based on the set
- * items-per-page). This makes it relativly easy to do a google-ish set
- * of links to result pages.</p>
- *
- * <p>Note that this list of Integers is 0-based to correspond with the
- * underlying result indices and not the displayed page numbers (see
- * [EMAIL PROTECTED] #getPageNumber}).</p>
+ * 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.
*
- * @return [EMAIL PROTECTED] List} of Integers representing the indices
of result
- * pages or empty list if there's one or less pages available
+ * @return [EMAIL PROTECTED] List} of all items for the criteria
*/
- public List getSlip()
+ public List getItems()
{
- /* return an empty list if there's no pages to list */
- int totalPgs = getPagesAvailable();
- if (totalPgs <= 1)
+ /* return empty list if we have no criteria */
+ if (criteria == null)
{
return Collections.EMPTY_LIST;
}
- /* page number is 1-based so decrement it */
- int curPg = getPageNumber().intValue() - 1;
-
- /* don't include current page in slip size calcs */
- int adjSlipSize = slipSize - 1;
+ /* get the current list */
+ List list = super.getItems();
- /* start at zero or just under half of max slip size
- * this keeps "forward" and "back" pages about even
- * but gives preference to "forward" pages */
- int slipStart = Math.max(0, (curPg - (adjSlipSize / 2)));
-
- /* push slip end as far as possible */
- int slipEnd = Math.min(totalPgs, (slipStart + adjSlipSize));
-
- /* if we're out of "forward" pages, then push the
- * slip start toward zero to maintain slip size */
- if (slipEnd - slipStart < adjSlipSize)
+ /* if empty, execute a query for the criteria */
+ if (list.isEmpty())
{
- slipStart = Math.max(0, slipEnd - adjSlipSize);
- }
+ /* perform a new query */
+ list = executeQuery(criteria);
- /* convert 0-based page numbers to indices and create list */
- List slip = new ArrayList((slipEnd - slipStart) + 1);
- for (int i=slipStart; i < slipEnd; i++)
- {
- slip.add(new Integer(i * itemsPerPage));
+ /* save the new results */
+ setItems(list);
}
- return slip;
+ return list;
}
- /* ---------------------- private methods -----------------------------
*/
-
+ /* ---------------------- protected methods
----------------------------- */
- /**
- * Gets the results for the given criteria either in memory
- * or by performing a new query for them. This is guaranteed to
- * NOT return null.
- */
- private List retrieveResults()
+ protected List getStoredItems()
{
- /* return empty list if we have no criteria */
- if (criteria == null)
- {
- return Collections.EMPTY_LIST;
- }
-
- /* get any stored results */
StoredResults sr = getStoredResults();
/* if the criteria equals that of the stored results,
@@ -565,21 +246,14 @@
{
return sr.getList();
}
-
- /* perform a new query and make sure we don't end up with a null
list */
- List list = executeQuery(criteria);
- if (list == null)
- {
- list = Collections.EMPTY_LIST;
- }
-
- /* save the new results */
- setStoredResults(new StoredResults(criteria, list));
- return list;
+ return null;
}
- /* ---------------------- protected methods
----------------------------- */
+ protected void setStoredItems(List items)
+ {
+ setStoredResults(new StoredResults(criteria, items));
+ }
/**
@@ -635,7 +309,6 @@
/* ---------------------- utility class -----------------------------
*/
-
/**
* Simple utility class to hold a criterion and its result list.
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