java - When to use a String with filename or File as argument to constructor? -

when should use file , when should use string filename constructor? constructed method should contain contents of file. can choose:

public graphmodel(file file) throws ioexception {     this();     readfromfile(file); } 

versus

public graphmodel(string filename) throws ioexception {     this();     readfromfile(new file(filename)); } 

is 1 preferred on other?

some people think matter of taste / personal preference ... or doesn't matter. argue matter.

lets assume api's implementation require file internally. then, there 3 alternative approaches:

  // #1   public graphmodel(file file) throws ioexception {...}    // #2   public graphmodel(string file) throws ioexception {...}    // #3   public graphmodel(file file) throws ioexception {...}   public graphmodel(string file) throws ioexception {       this(new file(file));   } 

now compare these apis in various contexts:

• if adopt approach #1, , caller has filename string must construct file. potentially results in duplicative code¹.

• if adopt approach #2, , caller has filename file must use file.tostring() argument constructor. potentially duplicative , inefficient².

• if adopt approach #3, api works in either case.

so conclusion is:

• if trying provide general api use in contexts you don't know form caller have filename, approach #3 best, , approach #2 better approach #1.

• if api not general; i.e. designing specific context, either approach #1 or #2 ok ... if fit intended usage patterns. however, might³ want design application don't keep on creating file objects same filenames.

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^{1 - if constructor called in lots of places, mean new file(...) call @ each place.}

^{2 - caller must convert file string, have constructor create new file string.}

^{3 - if aspect of application demonstrably performance critical.}