using switch block in java instead of multiple if statements
public class A {
public void search(boolean[] searchList) {
// searchList array is used to identify what options to search for in a given order
// e.g. boolean [] searchList = new boolean [] {false, false, true, false};
boolean searchL = false;
boolean searchM = false;
boolean searchK = false;
boolean searchA = false;
if(searchList[0] == true) searchL = true;
if(searchList[1] == true) searchM = true;
if(searchList[2] == true) searchK = true;
if(searchList[3] == true) searchA = true;
开发者_开发知识库
if(searchL == true) // write a query to search for all Ls
if(searchM == true) // write a query to search for all Ms
...........
}
Is there a way I can simplify this code ?
@All : Sorry for posting a wrong question before. I was confused!
Thanks, Sony
I am a big fan of enums:
public class A {
enum SearchType {
L, M, A, K;
}
public void search(SearchType type) {
switch (type) {
case L:
System.out.println("Searching for L");
break;
case M:
System.out.println("Searching for M");
break;
case A:
System.out.println("Searching for A");
break;
case K:
System.out.println("Searching for K");
break;
default:
System.out.println("what to do here?");
// throw exception?
}
note also: your scenario allowed more than one search boolean to be true at a time, I assumed that was not your goal, but if it is we can tweak this a bit.
You should convert your state into an enum. For example your search booleans seem to be exclusive so i would do something like this:
enum SearchOption {
searchA, searchK, searchL, searchM
}
// then you can do
SearchOption searchOption = searchA;
switch (searchOption) {
case searchA:
System.out.println("I am searching for A");
break;
case searchK:
System.out.println("I am searching for K");
break;
case searchL:
System.out.println("I am searching for L");
break;
case searchM:
System.out.println("I am searching for M");
break;
}
If your states aren't exclusive you should try build to build a super set of exclusive states initially.
Why don't employ OOP? Like:
public interface Seeker {
void seek();
}
public class LSeeker implements Seeker {
void seek() { System.out.println("Will search for L"); }
}
// ... More implementations of Seeker
public class SeekDriver {
void seek(Seeker seeker) { seeker.seek(); }
}
public class A {
public enum SearchOption {
SEARCH_L,
SEARCH_M,
SEARCH_A,
SEARCH_K;
}
/**
* Make them pass in an enum for your search.
* Pros: type safe, can only use the selections you give
* Cons: must add to the enum to add new types
* @param option
*/
public void enumSearch(SearchOption option) {
switch(option) {
case SEARCH_A:
System.out.println("I am searching for A");
break;
case SEARCH_K:
System.out.println("I am searching for K");
break;
case SEARCH_L:
System.out.println("I am searching for L");
break;
case SEARCH_M:
System.out.println("I am searching for M");
break;
}
}
/**
* Use a primitive for your input
* Pros: Gives you more options without updating the enum
* Cons: Users could enter input you don't really want them to use
* @param option
*/
public void charSearch(char option) {
switch(option) {
case 'a':
case 'A':
System.out.println("I am searching for A");
break;
case 'k':
case 'K':
System.out.println("I am searching for K");
break;
case 'l':
case 'L':
System.out.println("I am searching for L");
break;
case 'm':
case 'M':
System.out.println("I am searching for M");
break;
}
}
/**
* Use a primitive and don't even actually check it! Just run with it!
* @param option
*/
public void uncheckedSearch(char option) {
System.out.println("I am searching for " + option);
}
}
As per your comment, here's my updated example of that method - make sure the comment at the top is updated!
/**
* Perform the search based on the options provided
* The list should be in the order of L, M, A, K
* @note update this comment as more search options are added
* @param searchList the list of flags indicating what to search for
*/
public void search(boolean[] searchList) {
// as per docs, [0] denotes an L search:
if(searchList[0])
// write a query to search for all Ls
// as per docs, [1] denotes an M search:
if(searchList[1])
// write a query to search for all Ms
// as per docs, [2] denotes an A search:
if(searchList[2])
// write a query to search for all As
// as per docs, [3] denotes a K search:
if(searchList[3])
// write a query to search for all Ks
}
Latest idea:
// Use the SearchOption enum from above
Map<SearchOption, String> searches = new HashMap<SearchOption, String>();
public List<SearchResult> search(List<SearchOption> options) {
List<SearchResult> results = new LinkedList<SearchResult>();
for(SearchOption option : options) {
String query = searches.get(option);
SearchResult result = MySearchService.executeQuery(query);
results.add(result);
}
return results;
}
Like this: ?
public class A {
public void search() {
private static final int SEARCH_L = -1;
private static final int SEARCH_M = 0;
private static final int SEARCH_A = 1;
private static final int SEARCH_K = 2;
int status;
switch(status){
case SEARCH_L:
System.out.println("I am searching for L");
break;
case SEARCH_M:
System.out.println("I am searching for M");
break;
// Etc
default:
// Log error didn't hit a known status
break;
}
}
精彩评论