StructEach
Used to iterate over a struct and run the function closure for each key/value pair.
The function will be passed 3 arguments: the key, the value, and the struct. You can alternatively pass a Java BiConsumer which will only receive the first 2 args (key and value).
This BIF is useful for performing side effects on each item in the struct, such as logging or modifying external state.
Parallel Execution
If the parallel argument is set to true, and no max_threads are sent, the filter will be executed in parallel using a ForkJoinPool with parallel streams.
If max_threads is specified, it will create a new ForkJoinPool with the specified number of threads to run the filter in parallel, and destroy it after the operation is complete.
Please note that this may not be the most efficient way to iterate, as it will create a new ForkJoinPool for each invocation of the BIF. You may want to consider using a shared ForkJoinPool for better performance.
Method Signature
StructEach(struct=[structloose], callback=[function:BiConsumer], parallel=[boolean], maxThreads=[integer], ordered=[boolean])Arguments
struct
struct
true
The target struct to iterate
callback
function:BiConsumer
true
The function to invoke for each item. The function will be passed 3 arguments: the key, the value, the struct. You can alternatively pass a Java BiConsumer which will only receive the first 2 args.
parallel
boolean
false
Whether to run the filter in parallel. Defaults to false. If true, the filter will be run in parallel using a ForkJoinPool.
false
maxThreads
integer
false
The maximum number of threads to use when running the filter in parallel. If not passed it will use the default number of threads for the ForkJoinPool. If parallel is false, this argument is ignored.
ordered
boolean
false
(BoxLang only) whether parallel operations should execute and maintain order
false
Examples
structEach() with an inline function (closure)
Use a function to write out the keys in a structure to the screen
someStruct = {
A : 1,
B : 2,
C : 3
};
structEach( someStruct, ( Any key, Any value ) => {
writeOutput( "Key " & key & " is " & value & "; " );
} );
Result: Key a is 1; Key b is 2; Key c is 3;
Using a function reference
favs = {
COLOR : "blue",
FOOD : "pizza",
SPORT : "basketball"
};
// named function
// notice that the function takes two arguments, the key and value pair of the current iteration of the structure's key-value pairs
function getFavorites( Any key, Any value ) {
writeOutput( "My favorite " & key & " is " & value );
}
// run structEach() with a named function
structEach( favs, getFavorites );
// run structEach() with an inline function
structEach( favs, ( Any key, Any value ) => {
writeOutput( "My favorite " & key & " is " & value );
} );
Using the member function
statusCodes = {
OK : 200,
CREATED : 201,
NOT_MODIFIED : 304,
BAD_REQUEST : 400,
NOT_FOUND : 404
};
statusCodes.each( ( Any key, Any value ) => {
writeOutput( "#key# => #value#<br />" );
} );
Result: NOT_FOUND => 404 BAD_REQUEST => 400 CREATED => 201 OK => 200 NOT_MODIFIED => 304
Accessing a reference to the looping struct in the callback
statusCodes = {
OK : 200,
CREATED : 201,
NOT_MODIFIED : 304,
BAD_REQUEST : 400,
NOT_FOUND : 404
};
statusCodes.each( ( Any key, Any value, Any struct ) => {
writeDump( struct );
} );
Additional Examples
animals = {
COW : "moo",
PIG : "oink",
CAT : "meow"
};
StructEach( animals, ( Any key ) => {
// Show key 'arguments.key'
Dump( label="Key", var=arguments.KEY );
// Show key's value 'animals[arguments.key]'
Dump( label=arguments.KEY & "'s value", var=animals[ arguments.KEY ] );
} );
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