Add code to main in the HashTableTester.java file so it ALSO declares a HashSC<L

ID: 3843839 • Letter: A

Question

Add code to main in the HashTableTester.java file so it ALSO declares a HashSC<Location> variable and adds at least 3 Location objects to it AND test it similar to how the HashSC<Employee> is tested. MAKE SURE YOU KEEP THE EXISTING CODE IN main (DON'T REMOVE ANY EXISTING CODE)!!!

ADD to the Location class here in the Location.java file (in the "Hash Table Files" link in Catalyst) so it overrides the equals method (compare ONLY the name) AND the hashCode method (use the body of the Hash method shown on page 2, but instead of someStringMember, do the operations on the Location's latitude & longitude as described below).

The Locations' hashCode method is assign to a local variable the latitude + 90, and to another local variable the longitude+180. Then convert each of those into a String (saving in local variables), BUT using a DecimalFormat with "000.0000" (will be shown in the Class Notes for 05-17). Remove the decimal points in each String, concatenate the 2 Strings, and return the hashCode of the resulting String). (You'll need to import java.text.*; )

HashTableTester.java:

   //Example of an Employee class (to be used in main below)
   class Employee
   {
   public static final int MAX_LEN = 50;

private String name;
private int ss;

   public Employee( String name , int ss)
   {
   this();
   setName(name);
   setSS(ss);
   }

   public Employee()
   {
   name = "undefined";
   ss = 0;
   }

String getName() { return name; }
int getSS() { return ss; }

   boolean setName( String name )
   {
   if (name == null)
   return false;
   if (name.length() > MAX_LEN)
   return false;
   this.name = name;
   return true;
   }

   boolean setSS( int ss )
   {
   if (ss < 0 || ss > 999999999 )
   return false;
   this.ss = ss;
   return true;
   }

   public String toString()
   {
   return name + " (" + ss + ")";
   }

   public boolean equals( Object rhs ) // UPDATED!
   {
   return name.equalsIgnoreCase(((Employee)rhs).name);
   }

   public int hashCode()
   {
   return ss;
   // return name.hashCode(); // another possibility
   }
   };

public class HashTableTester {

   // ------- main --------------
   public static void main(String[] args) throws Exception
   {
   // first set of tests --------------------
   HashSC<Employee> hashTable = new HashSC<Employee>();

   Employee
   e1 = new Employee("Jane Austin", 1),
   e2 = new Employee("Rene Descartes", 2),
   e3 = new Employee("John Locke", 3);

   if ( hashTable.insert(e1) )
   System.out.println( "inserted " + e1 );
   if ( hashTable.insert(e1) )
   System.out.println( "inserted " + e1 );
   if ( hashTable.insert(e2) )
   System.out.println( "inserted " + e2 );
   if ( hashTable.insert(e2) )
   System.out.println( "inserted " + e2 );
   if ( hashTable.insert(e3) )
   System.out.println( "inserted " + e3 );
   if ( hashTable.insert(e3) )
   System.out.println( "inserted " + e3 );

System.out.println( hashTable.size() );

if ( hashTable.contains(e3) )
System.out.println( "contains " + e3 );

   if ( hashTable.remove(e1) )
   System.out.println( "removed " + e1 );
   if ( hashTable.remove(e1) )
   System.out.println( "removed " + e1 );
   if ( hashTable.remove(e2) )
   System.out.println( "removed " + e2 );
   if ( hashTable.remove(e2) )
   System.out.println( "removed " + e2 );
   if ( hashTable.remove(e3) )
   System.out.println( "removed " + e3 );
   if ( hashTable.remove(e3) )
   System.out.println( "removed " + e3 );
   System.out.println( hashTable.size() );

if ( hashTable.contains(e3) )
System.out.println( "contains " + e3 );

// second set of tests --------------------

   HashSC<String> hashTable2 = new HashSC<String>();
   String substrate =
   "asdlkfj asdoiBIUYVuwer slkdjLJfwoe89)B)(798rjMG0293lkJLJ42lk3j)(*";
   String[] strArray = new String[500];
   int k, limit;

substrate = substrate + substrate;

   for (k = 0; k < substrate.length() - 6; k++)
   strArray[k] = substrate.substring(k, k + 5);
   limit = k;

   hashTable2.setMaxLambda(.5);
   for (k = 0; k < limit; k++)
   if ( hashTable2.insert(strArray[k]) )
   System.out.println( "inserted #" + k + " " + strArray[k] );
   System.out.println( " #strings generated: " + limit
   + " #elements in ht: " + hashTable2.size() );
   } // end main

}

Location.java:

public class Location {
   private String name="";
   private String address="";
   private double latitude; // default 0
   private double longitude; // default 0

   public Location(String nm, String addr, double lat, double lon)
   {
       setName(nm);
       setAddress(addr);
       setCoordinates(lat, lon);
   }

   public Location(String nm)
   {
       setName(nm);
   }

   public void setName(String nm)
   {
       if( nm != null )
           name = nm;
   }

   public void setAddress(String addr)
   {
       if( addr != null )
           address = addr;
   }

   public void setCoordinates(double lat, double lon)
   {
       latitude = lat;
       longitude = lon;
   }

   public String getName(){ return name; }

   public String getAddress(){ return address; }

   public double getLatitude(){ return latitude; }

   public double getLongitude(){ return longitude; }

   public String toString()
   {
       return "Location: "+ name + ", " + address +
               ", (" + latitude + ", " + longitude + ")";
   }

   // YOU WRITE equals: public boolean equals(Object obj)

   // YOU WRITE hashCode: public int hashCode()
}

Explanation / Answer

import java.text.DecimalFormat;

class Employee
{
public static final int MAX_LEN = 50;
private String name;
private int ss;
public Employee( String name , int ss)
{
this();
setName(name);
setSS(ss);
}
public Employee()
{
name = "undefined";
ss = 0;
}
String getName() { return name; }
int getSS() { return ss; }
boolean setName( String name )
{
if (name == null)
return false;
if (name.length() > MAX_LEN)
return false;
this.name = name;
return true;
}
boolean setSS( int ss )
{
if (ss < 0 || ss > 999999999 )
return false;
this.ss = ss;
return true;
}
public String toString()
{
return name + " (" + ss + ")";
}
public boolean equals( Object rhs ) // UPDATED!
{
return name.equalsIgnoreCase(((Employee)rhs).name);
}
public int hashCode()
{
return ss;
// return name.hashCode(); // another possibility
}
};

public class HashTableTester {
// ------- main --------------
public static void main(String[] args) throws Exception
{
// first set of tests --------------------
HashSC<Employee> hashTable = new HashSC<Employee>();
Employee
e1 = new Employee("Jane Austin", 1),
e2 = new Employee("Rene Descartes", 2),
e3 = new Employee("John Locke", 3);
if ( hashTable.insert(e1) )
System.out.println( "inserted " + e1 );
if ( hashTable.insert(e1) )
System.out.println( "inserted " + e1 );
if ( hashTable.insert(e2) )
System.out.println( "inserted " + e2 );
if ( hashTable.insert(e2) )
System.out.println( "inserted " + e2 );
if ( hashTable.insert(e3) )
System.out.println( "inserted " + e3 );
if ( hashTable.insert(e3) )
System.out.println( "inserted " + e3 );
System.out.println( hashTable.size() );
if ( hashTable.contains(e3) )
System.out.println( "contains " + e3 );
if ( hashTable.remove(e1) )
System.out.println( "removed " + e1 );
if ( hashTable.remove(e1) )
System.out.println( "removed " + e1 );
if ( hashTable.remove(e2) )
System.out.println( "removed " + e2 );
if ( hashTable.remove(e2) )
System.out.println( "removed " + e2 );
if ( hashTable.remove(e3) )
System.out.println( "removed " + e3 );
if ( hashTable.remove(e3) )
System.out.println( "removed " + e3 );
System.out.println( hashTable.size() );
if ( hashTable.contains(e3) )
System.out.println( "contains " + e3 );
// second set of tests --------------------
HashSC<String> hashTable2 = new HashSC<String>();
String substrate =
"asdlkfj asdoiBIUYVuwer slkdjLJfwoe89)B)(798rjMG0293lkJLJ42lk3j)(*";
String[] strArray = new String[500];
int k, limit;
substrate = substrate + substrate;
for (k = 0; k < substrate.length() - 6; k++)
strArray[k] = substrate.substring(k, k + 5);
limit = k;
hashTable2.setMaxLambda(.5);
for (k = 0; k < limit; k++)
if ( hashTable2.insert(strArray[k]) )
System.out.println( "inserted #" + k + " " + strArray[k] );
System.out.println( " #strings generated: " + limit
+ " #elements in ht: " + hashTable2.size() );
} // end main
}

public class Location {
private String name="";
private String address="";
private double latitude; // default 0
private double longitude; // default 0

public Location(String nm, String addr, double lat, double lon)
{
setName(nm);
setAddress(addr);
setCoordinates(lat, lon);
}

public Location(String nm)
{
setName(nm);
}

public void setName(String nm)
{
if( nm != null )
name = nm;
}

public void setAddress(String addr)
{
if( addr != null )
address = addr;
}

public void setCoordinates(double lat, double lon)
{
latitude = lat;
longitude = lon;
}

public String getName(){ return name; }

public String getAddress(){ return address; }

public double getLatitude(){ return latitude; }

public double getLongitude(){ return longitude; }

public String toString()
{
return "Location: "+ name + ", " + address +
", (" + latitude + ", " + longitude + ")";
}

// YOU WRITE equals: public boolean equals(Object obj)

// YOU WRITE hashCode: public int hashCode()
@Override
public boolean equals(Object obj)
{
   String compName;
   if(obj instanceof Location)
       compName=((Location)obj).name;
   else
       compName="";
   return name.equalsIgnoreCase(compName);
}

public int hashcode()
{
   String latString, lonString, resultStr;
   DecimalFormat decFormat= new DecimalFormat("000.0000");
   latString=decFormat.format(latitude+90.);
   lonString=decFormat.format(longitude+180.);
   resultStr = latString.replace(".", "") + lonString.replace(".", "");
   return resultStr .hashCode();

}
}

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Add code to main in the HashTableTester.java file so it ALSO declares a HashSC<L

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