search from array list

[infernocy]

Hallo
This is method inside a a depot class that search the vehicle class and shows the vehicles by their maker
the problem at the moment is that it shows both the null and the cars at the same time ,if a car is there -

public Vehicle find(String findMaker)
    {
        for (Vehicle a : vehicleList)
        {
            if (a.GetMake() == findMaker )

                System.out.println(a);

             
        }
          return null ;      
   }

[JosAH]

Don't compare Strings for equality with the == operator; use the equals( ... ) method and read the API documentation for the String class to see why.

kind regards,

Jos

[Honore]

What's your problem? Do you want your method to be able to return a null value or output the car maker?

[infernocy]

the method should return the vehicle if found , so i think its better if i change to show nothing if not found , the problem is at the moment it shows both at the same time ( the null value and the car found )

[JosAH]

Is my reply written in invisible ink again?

kind regards,

Jos

[infernocy]

JosAh i am looking at the APi documentation and i did read you reply --- i am still new in java

[sehudson]

What does your output look like?

From what you have posted, your output will be the toString() method for your Vehicle class.

The toString() method for the Object class returns a string containing the name of the class of which the object is an instance, the @ sign, and the unsigned hex representation of the hash code of the object.

You can override the toString() method and write your own, if that is what you are trying to have displayed. Maybe you just want to have the find method return a Vehicle object where the maker is equal to findMaker.

public Vehicle find(String findMaker)
    {
        for (Vehicle a : vehicleList)
        {
            if (a.GetMake() == findMaker ) 
                return a;   
        }
          return null ;     
   }

[infernocy]

What does your output look like?

From what you have posted, your output will be the toString() method for your Vehicle class.

The toString() method for the Object class returns a string containing the name of the class of which the object is an instance, the @ sign, and the unsigned hex representation of the hash code of the object.

You can override the toString() method and write your own, if that is what you are trying to have displayed. Maybe you just want to have the find method return a Vehicle object where the maker is equal to findMaker.

public Vehicle find(String findMaker)
    {
        for (Vehicle a : vehicleList)
        {
            if (a.GetMake() == findMaker ) 
                return a;   
        }
          return null ;     
   }

i input a car maker and it should search the vehicle list and list all the Vehicles by that maker ,at the moment if there is a list of vehicles , it will return the null value as well as the toString method , i want to correct it so it will not return null if there are some cars , but i think its better if it will do nothing if there are no cars by that maker .

[must0995]

try if (a.GetMake().equals( findMaker) )

[infernocy]

try if (a.GetMake().equals( findMaker) )

ah i forgot to mention that i already change that
it will return the null value as well as show the output of the toString method inside the vehicle class , i want to correct it so it will not return the null value if there are some cars, but i think its better if i replace the returned null value with do nothing , so it will not do anything is there are no cars by that maker in the vehicle list

public Vehicle find(String findMaker)
{
for (Vehicle a : vehicleList)
{
if (a.GetMake().equals(findMaker ))


System.out.println(a);
}
return null;
}

[Honore]

public static String find(String findMaker)
{
int numVehicles = 0;
Vehicle v = null;

for (Vehicle a : vehicleList)
{
if (a.GetMake().equals(findMaker ))
{
System.out.println(a);
numVehicles++;
v = a;
}
}
if(numVehicles > 0)
{
return v;
}
else
{
return null;
}
}

[Honore]

ah i forgot to mention that i already change that
it will return the null value as well as show the output of the toString method inside the vehicle class , i want to correct it so it will not return the null value if there are some cars, but i think its better if i replace the returned null value with do nothing , so it will not do anything is there are no cars by that maker in the vehicle list

public static String find(String findMaker)
{
int numVehicles = 0;
Vehicle v = null;

for (Vehicle a : vehicleList)
{
if (a.GetMake().equals(findMaker ))
{
System.out.println(a);
numVehicles++;
v = a;
}
}
if(numVehicles > 0)
{
return v;
}
else
{
return null;
}
}

[Honore]

public static String find(String findMaker)
{
int numVehicles = 0;
Vehicle v = null;

for (Vehicle a : vehicleList)
{
if (a.GetMake().equals(findMaker ))
{
System.out.println(a);
numVehicles++;
v = a;
}
}
if(numVehicles > 0)
{
return v;
}
else
{
return null;
}
}

The "find method" will return a null value if the warehouse does not have a vehicle by that maker. If it does, then the "find method" will output the vehicle's name to the console and also return it to the calling method. If you want the "find method" to return nothing if a vehicle is found, then you must change the return value to void.

[infernocy]

Thanks Honore for the code it works

[Honore]

The "find method" will return a null value if the warehouse does not have a vehicle by that maker. If it does, then the "find method" will output the vehicle's name to the console and also return it to the calling method. If you want the "find method" to return nothing if a vehicle is found, then you must change the return value to void.

No problem.