Gonçalo Marques created COLLECTIONS-550:
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Summary: Provide a simple way for creating an arbitrary String
representation of a given Iterable
Key: COLLECTIONS-550
URL: https://issues.apache.org/jira/browse/COLLECTIONS-550
Project: Commons Collections
Issue Type: New Feature
Components: Collection
Affects Versions: 4.0
Reporter: Gonçalo Marques
Priority: Minor
Create an utility method that returns an arbitrary {{String}} representation of
a given {{Iterable}}, where for each {{Iterable}} element one may require a
{{String}} representation that is different from the element's own
{{toString()}} result.
Additionally the client may also provide an optional delimiter, where the
default one could be the common {{", "}}.
The transformation of each {{Iterable}} element into an arbitrary {{String}}
could be implemented by the means of a {{Transformer}}.
Example (illustrative method in {{CollectionUtils}}):
{code}
static <C> String toString(Iterable<C> iterable, Transformer<C, String>
transformer);
{code}
Consider the following illustrative class:
{code}
class SomeClass {
private final String propertyOne;
private final String propertyTwo;
public SomeClass(String propertyOne, String propertyTwo) {
this.propertyOne = propertyOne;
this.propertyTwo = propertyTwo;
}
public String getPropertyOne() {
return propertyOne;
}
public String getPropertyTwo() {
return propertyTwo;
}
@Override
public String toString() {
return propertyOne;
}
}
{code}
One could transform an {{Iterable}} containing elements of type {{SomeClass}}
into a client provided {{String}} representation by calling:
{code}
// list contains elements of type SomeClass
String result = CollectionUtils.transform(list, new Transformer<SomeClass,
String>() {
@Override
public String transform(SomeClass someClass) {
return someClass.getPropertyTwo();
}
});
// Will print "propertyTwoA, propertyTwoB"
System.out.println(result);
result = CollectionUtils.transform(list, new Transformer<SomeClass, String>() {
@Override
public String transform(SomeClass someClass) {
return someClass.getPropertyOne() + someClass.getPropertyTwo();
}
});
// Will print propertyOneApropertyTwoA, propertyOneBpropertyTwoB
System.out.println(result);
{code}
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