-1 to the ASC/DESC bit. That shouldn't be in comparators in my opinion,
instead use the ReverseComparator.
What is Polarity vs Property?
On Fri, 7 Jun 2002, Eric Pugh wrote:
> I forged ahead.. I had a need to sort in asc/desc... so I have added a
> sortPolarity and sortProperty methods..
>
> Here is what I created...
>
> package com.upstate.util;
>
> import org.apache.commons.beanutils.WrapDynaBean;
> import org.apache.commons.beanutils.*;
>
> import org.apache.log4j.Category;
>
> /**
> * Description of the Class
> *
> *@author epugh
> *@created May 5, 2002
> */
> public class BeanMethodComparator implements java.util.Comparator {
>
> public final static String ASC = "ASC";
> public final static String DESC = "DESC";
>
> private static Category log = Category.getInstance(
> BeanMethodComparator.class.getName() );
> private String sortProperty;
> private String sortPolarity = "ASC";
>
> /** Constructor for the BeanMethodComparator object */
> public BeanMethodComparator() { }
>
> /**
> * Constructor for the BeanMetodComparator object
> *
> *@param sortProperty Description of Parameter
> *@param sortPolarity Description of Parameter
> */
> public BeanMethodComparator( String sortProperty, String sortPolarity ) {
> setSortProperty( sortProperty );
> setSortPolarity( sortPolarity );
> }
>
> /**
> * Sets the sortProperty attribute of the SortDaughterboard object
> *
> *@param sortProperty The new sortProperty value
> */
> public void setSortProperty( String sortProperty ) {
> this.sortProperty = sortProperty;
> }
>
> /**
> * Sets the sortPolarity attribute of the SortDaughterboard object
> *
> *@param sortPolarity The new sortPolarity
> value.
> * Can be either "ASC"/"DESC".
> *@exception java.lang.IllegalArgumentException Thrown if you pass in a
> bad
> * sortPolarity.
> */
> public void setSortPolarity( String sortPolarity )
> throws java.lang.IllegalArgumentException {
> sortPolarity = sortPolarity.toUpperCase();
> if ( sortPolarity.equals( ASC ) || sortPolarity.equals( DESC ) ) {
> throw new java.lang.IllegalArgumentException( "The argument:" +
> sortPolarity + " was invalid." );
> }
> this.sortPolarity = sortPolarity;
> }
>
> /**
> * Gets the sortPolarity attribute of the SortDaughterboard object
> *
> *@return The sortPolarity value
> */
> public String getSortPolarity() {
> return sortPolarity;
> }
>
>
> /**
> * Gets the sortProperty attribute of the SortDaughterboard object
> *
> *@return The sortProperty value
> */
> public String getSortProperty() {
> return sortProperty;
> }
>
> /**
> * Description of the Method
> *
> *@param o1 Description of Parameter
> *@param o2 Description of Parameter
> *@return Description of the Returned Value
> */
> public int compare( Object o1, Object o2 ) {
> try {
> WrapDynaBean bean1 = new WrapDynaBean( o1 );
> WrapDynaBean bean2 = new WrapDynaBean( o2 );
>
> Comparable value1 = (Comparable) bean1.get( sortProperty );
> Comparable value2 = (Comparable) bean2.get( sortProperty );
>
> int sort = 0;
>
> if ( ( value1 == null ) & ( value2 == null ) ) {
> sort = 0;
> }
> else if ( value1 == null & value2 != null ) {
> sort = 1;
> }
> else if ( value1 != null & value2 == null ) {
> sort = -1;
> }
> else {
> sort = value1.compareTo( value2 );
> }
>
> if ( sortPolarity.equals( DESC ) ) {
> sort = sort * -1;
> }
>
> return sort;
> }
>
> catch ( Exception e ) {
> log.error( "Problem in Sort. sortPolarity:" + sortPolarity + ",
> sortProperty:" + sortProperty, e );
> return 0;
> }
> }
>
> }
>
> Eric Pugh
>
>
> -----Original Message-----
> From: Henri Yandell [mailto:[EMAIL PROTECTED]]
> Sent: Friday, June 07, 2002 10:50 AM
> To: Jakarta Commons Developers List
> Subject: Re: [COLLECTIONS/BEANUTILS] Is there a comparator that can
> dynamically pick a method to call on a bean?
>
>
>
> I don't think there is one in Commons yet. I've had one for myself for a
> bit and it can be a lifesaver sometimes.
>
> BeanComparator bc = new BeanComparator("[1]"); was very sweet when I
> realised that would work :) Not just Beans but also arrays/collections.
>
> I'm +1 for a BeanComparator, +1 in that I plan to do it sometime but have
> not had the time to learn the Jakarta BeanUtils and stop using my own.
>
> Hen
>
> On Fri, 7 Jun 2002, Eric Pugh wrote:
>
> > Hi all,
> >
> > I have a series of Torque objects that I want to sort. Sometimes I want
> to
> > sort by MethodA, sometiems by MethodB. (Basically mapping onto all the
> > columns in my database).
> >
> > Right now, I have a comparator compare method that looks like this:
> > public int compare( Object o1, Object o2 ) {
> > Daughterboard db1 = (Daughterboard) o1;
> > Daughterboard db2 = (Daughterboard) o2;
> > int sort = 0;
> > if ( sortMethod.equals( "ScintillationFileNumber" ) ) {
> > /*
> > * if ( db1 == null == db2 ) {
> > * return 0;
> > * }
> > * else if (db1 == null &&
> > */
> > sort = Strings.clean( db1.getScintillationFileNumber()
>).compareTo(
> > Strings.clean( db2.getScintillationFileNumber() ) );
> >
> > }
> > else if ( sortMethod.equals( "DaughterboardId" ) ) {
> > sort = db1.getDaughterboardId().compareTo(
>db2.getDaughterboardId() );
> > }
> > if ( sortPolarity.equals( "desc" ) ) {
> > sort = sort * -1;
> > }
> >
> > return sort;
> > }
> >
> > What I really want to do is pass in a sortMethod like
> > ScintillationFileNumber, and dynamically call the objects getter for that
> > name. If I wrap my object in a WrapDynaBean, and use that to call the
> data,
> > will is actually change the ordering of my objects? Or should I just use
> > the WrapDynaBean locally inside of my compare method to facilitate calling
> > the methods?
> >
> > First time using BeanUtils, but it looks great..
> >
> > Lastly, would a comparator like this be something of general interest to
> add
> > to the collections list of comparators?
> >
> > Eric
> >
> >
> >
> > --
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> >
> >
>
>
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