I have an ArrayList filled POJOs and I want to remove all POJOs, which have a duplicate variable. This is the POJO:
public static class UrlStore {
public String url;
public String data;
public UrlStore(String url) {
this.url = url;
}
public void setData(String data) {
this.data = data;
}
}
My way to remove duplicate "url"-variables in the ArrayList<UrlStore> is to iterate through the list and to remove those duplicates. It was said to me that I could simply use a Set to do this, but I can't figure out how to use it with an ArrayList containing POJOs. Or do you have even a better way?
Thanks for any suggestions!
package test.urlstore;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
public class DuplicateDemo{
public static void main(String[] args) throws Exception {
List<UrlStore> urlStores = new ArrayList<UrlStore>();
UrlStore usg = new UrlStore("google");
UrlStore usy = new UrlStore("yahoo");
UrlStore usb = new UrlStore("bing");
UrlStore usa = new UrlStore("ask");
UrlStore usd = new UrlStore("duckduckgo");
usg.setData("mail");
urlStores.add(usg);
usg = new UrlStore("google");
usg.setData("search");
urlStores.add(usg);
usg = new UrlStore("google");
usg.setData("doc");
urlStores.add(usg);
usg = new UrlStore("google");
usg.setData("search");
urlStores.add(usg);
usg = new UrlStore("google");
usy.setData("search");
urlStores.add(usy);
usy.setData("search");
urlStores.add(usy);
usb.setData("search");
urlStores.add(usb);
usb.setData("search");
urlStores.add(usb);
usa.setData("search");
urlStores.add(usa);
usd.setData("search");
urlStores.add(usd);
System.out.println("before removing duplicates");
// before removing duplicates
for (Iterator iterator = urlStores.iterator(); iterator.hasNext();) {
UrlStore urlStore = (UrlStore) iterator.next();
System.out.println(urlStore.toString());
}
System.out.println("\n\nafter removing duplicates");
//removing duplicates
Set<UrlStore> uniqueUrlStores = new HashSet<UrlStore>(urlStores);
//After removing duplicates
for (Iterator iterator = uniqueUrlStores.iterator(); iterator.hasNext();) {
UrlStore urlStore = (UrlStore) iterator.next();
System.out.println(urlStore.toString());
}
}
static class UrlStore {
public String url;
public String data;
public UrlStore(String url) {
this.url = url;
}
public void setData(String data) {
this.data = data;
}
@Override
public String toString() {
return "UrlStore [url=" + url + ", data=" + data + "]";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((data == null) ? 0 : data.hashCode());
result = prime * result + ((url == null) ? 0 : url.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
UrlStore other = (UrlStore) obj;
if (data == null) {
if (other.data != null)
return false;
} else if (!data.equals(other.data))
return false;
if (url == null) {
if (other.url != null)
return false;
} else if (!url.equals(other.url))
return false;
return true;
}
}
}
Collected from the Internet
Please contact [email protected] to delete if infringement.
Comments