search method in business layer

[Ethem Yuksel]

Hi to all,
There are many topics mentioned about search algorithm. But i need a few code fragments how to accomplish the search function in business layer not in data. Data layer will make a search with the all fields starts with criteria[n]. Business layer will filter data's find results with the "equals". This is clear.

But how is it supposed to be combine these two items? What should be the simplest way? I have written something but looking forward to something simpler.

Thanks..

[K. Tsang]

Well Ethem, why you want to implement the search in the "business layer" when searching is one of those required methods in the Data class?

Business layer will filter data's find results with the "equals". This is clear.

What you mean by "equals"? Are you using the comparator or comparable interface to do the searching? Some code will help others what you done so far.

[Alecsandru Cocarla]

Ethem Yuksel wrote:What should be the simplest way? I have written something but looking forward to something simpler.

Well, what did you implement so far? Maybe we could help you improve it.

[Andrew Monkhouse]

K. Tsang wrote:why you want to implement the search in the "business layer" when searching is one of those required methods in the Data class?

I would imagine that he would want to do this because of the different requirements.

The Data layer only requires a "begins with" matching.
The presentation layer requires an "exact match".

Therefore you must have different logic in two separate areas.

Andrew

[Ethem Yuksel]

@Andrew, exactly right you are.
@Alec, my implementation is as the following. It is working but it really sucks How can i make it simpler? Regards...

                //client sends the request in a 3 element array
		String nameQuery = query[0];
		String locationQuery = query[1];
		String operator = query[2];
		List<Contractor> list = new ArrayList<Contractor>();
		
		if (operator.equals("AND")) {
			String[] criteria = {nameQuery, 
								 locationQuery, 
								 null, 
								 null, 
								 null, 
								 null};
			int[] ids = database.find(criteria);
			for (int recNo : ids) {
				try {
					String[] record = database.read(recNo);
					if (nameQuery != null && !record[0].equals(nameQuery)) {
						continue;
					} else if (locationQuery != null && !record[1].equals(locationQuery)) {
						continue;
					} else {
						list.add(composeContractorData(record));
					}
				} catch (RecordNotFoundException re) {
					LogManager.getDBLogger().warning(recNo 
							+ " record not found");
				}
			}
			
		} else { //if OR
			//according to the name query
			String[] nameCriteria = {nameQuery, 
					 null, 
					 null, 
					 null, 
					 null, 
					 null};
			int[] ids = database.find(nameCriteria);
			for (int recNo : ids) {
				try {
					String[] record = database.read(recNo);
					if (nameQuery != null && !record[0].equals(nameQuery)) {
						continue;
					} else {
						list.add(composeContractorData(record));
					}
				} catch (RecordNotFoundException re) {
					LogManager.getDBLogger().warning(recNo 
							+ " record not found");
				}
			}
			
			//according to the location query
			String[] locationCriteria = {null, 
					 locationQuery, 
					 null, 
					 null, 
					 null, 
					 null};
			ids = database.find(locationCriteria);
			for (int recNo : ids) {
				try {					
					String[] record = database.read(recNo);
					if (locationQuery != null && !record[1].equals(locationQuery)) {
						continue;
					} else {
						list.add(composeContractorData(record));
					}
				} catch (RecordNotFoundException re) {
					LogManager.getDBLogger().warning(recNo 
							+ " record not found");
				}
			}
			
		} //end of else		
		return new DbResponse(list);

[Fola Fadairo]

ClientData extends Data{

       public List<Room> findAll(){
              return this.find(new String[7]);
       }

       public List<Room> findNameOrLocation(String name, String location){
               //probably verify that name and location are not null
               List<Room> results = new ArrayList<Room>();
               for(Room r : this.findAll(){
                    String n = r.getName();
                    String l = r.getLocation();
                    if(n.equalsIgnoreCase(name) || l.equalsIgnoreCase(location){
                           results.add(r);
                    }
               }
               return results;
       }

       public List<Room> findNameAndLocation(String name, String location){
               //probably verify that name and location are not null
               List<Room> results = new ArrayList<Room>();
               for(Room r : this.findAll(){
                    String n = r.getName();
                    String l = r.getLocation();
                    if(n.equalsIgnoreCase(name) && l.equalsIgnoreCase(location){
                           results.add(r);
                    }
               }
               return results;
       }
}

Looks okay to me. I find it readable and easy to understand, especially for a junior programmer.

[Kevin Florish]

Hi Fola

Not sure what the spec requirements are for your assignment.

I have done B&S 2.2.1 and the implementation of the DBAccess interface requires a possible search on all fields.

I use a Contractor class as an O-O framework which helps with the search functionality and use booleans for each field passed.

If the passed field is set to true then I check the value against my active Contractor record. Its a bit long winded but easy for a junior programmer to understand. Here's a snippet of code to explain what I mean.

contractorCacheLock.readLock().lock();
Set<Long> recNoSet = new TreeSet<Long>(contractorCache.keySet());
int recNoIdx = 0;
for (Long s : recNoSet) {
    Contractor contractor = contractorCache.get(s);
    /*
     * Check if record is deleted 
     */
    for (int i = 0; i < 1; i++) {
        if (contractor.getDeletedFlag().equals("1")) {
            log.fine(Thread.currentThread().getName()
            + " Contractor: " + contractor.getName() 
            + " , " + contractor.getLocation() 
            + " has deletion flag set");
            break;
        } 
        if (searchName) {
           /*
            * Searched on name
            */
           if (!criteria[0].equals("") && !contractor.getName().startsWith(criteria[0])) {
               break;	
           }
       }
       ...
       if (searchSpecialities) {
           /*
            * Searched on staff specialities
            */
           if (!contractor.getSpecialities().startsWith(criteria[2])) { 
               break;
           }
       }
       ... 				}
       recNos[recNoIdx] = s;
       recNoIdx += 1;

[Fola Fadairo]

Hello Kevin,
I have URLyBird. The thread is about the search requirements on the business side. Part of the requirements state:

"It must allow the user to search the data for all records, or for records where the name and/or location fields exactly match values specified by the user"

I understand this to mean, String.equals(...) or String.equalsIgnoreCase(...). The code I posted demonstrates the way which appears most intuitive to me. There are probably easier and more efficient ways to do it, but I like the simplicity of the code.

The find method returns an array of integers, so the code will not work as posted, one will still have some fun providing a working implementation.

Regards,
Fola

[Bert Bates]

Hi Guys,

It's always a tough call when to say that a thread is getting a little too detailed in this forum... this one is making me a bit uncomfortable, let's back off the details a bit!

Thanks,

Bert

[Alecsandru Cocarla]

Ethem Yuksel wrote:@Alec, my implementation is as the following. It is working but it really sucks How can i make it simpler?

What I did is very similar to yours, just that I did not provide "OR" functionality (which makes everything much simpler ).
I also used a Filter object instead of plain parameters or the query[] you're using. This makes everything much easier to extend later with new criteria.
You should also break down your code into more methods, to make it easier to understand and manage.

[Nicolas Zozol]

Kevin Florish wrote:

       if (searchSpecialities) {
           /*
            * Searched on staff specialities
            */
           if (!contractor.getSpecialities().startsWith(criteria[2])) { 
               break;
           }
       }

Hi,
This implementation is absolutely logical, but the definition of the find says that search seek the start of the field.

  
// Returns an array of record numbers that match the specified
// criteria. Field n in the database file is described by
// criteria[n]. A null value in criteria[n] matches any field
// value. A non-null  value in criteria[n] matches any field
// value that begins with criteria[n]. (For example, "Fred"
// matches "Fred" or "Freddy".)
    public int[] find(String[] criteria)  throws RecordNotFoundException;

  

Aren't you afraid to fail with this search ? Should this be an option (and therefore it brings no more points !) ? One point however is that the interface method documentation doesn't say must.

[Roel De Nijs]

Hi Nicolas,

I actually don't see the problem. The comments of the find-method: criteria[n] matches any field value that begins with criteria[n]. And that's what the code of Kevin Florish exactly does! So why would he be afraid to fail? I also used the startsWith-method, just like him.

Kind regards,
Roel

[Nicolas Zozol]

Roel De Nijs wrote:Hi Nicolas,

I actually don't see the problem. The comments of the find-method: criteria[n] matches any field value that begins with criteria[n]. And that's what the code of Kevin Florish exactly does! So why would he be afraid to fail? I also used the startsWith-method, just like him.

Kind regards,
Roel

Oups, I read too fast Because specilities was separate, I thought it had a special treatment : the one I was discussing of, and working on. Like lot of scientists says, you read what your brain is ready to read....