T - the type of elements to join.public final class AppendableJoiner<T> extends Object
Iterable into an existing Appendable like a StringBuilder; with the goal for call sites to avoid creating
intermediary Strings. This is like String.join(CharSequence, CharSequence...), String.join(CharSequence, Iterable), and StringJoiner.
Keep an instance in a (static) variable for efficient joining into an Appendable or StringBuilder without creating temporary Strings.
Use the builder and instance methods to reuse the same kind of joining prefix, suffix, delimiter, and string conversion.
For example:
// A reuseable instance
private static final AppendableJoiner<Object> JOINER = AppendableJoiner.builder()
.setPrefix("[")
.setSuffix("]")
.setDelimiter(", ")
.get();
...
// Builds straight into a StringBuilder:
StringBuilder sbuilder = new StringBuilder("1");
JOINER.join(sbuilder, "A", "B");
sbuilder.append("2");
JOINER.join(sbuilder, "C", "D");
sbuilder.append("3");
// Returns "1[A, B]2[C, D]3"
return sbuilder.toString();
}
To provide a custom Object element to CharSequence converter, call AppendableJoiner.Builder.setElementAppender(FailableBiConsumer), for example:
private static final AppendableJoiner<Item> JOINER = AppendableJoiner.builder()
.setElementAppender(e -> (a, e) -> a.append(e.getFoo())
a.append(e.getBar())
a.append('!'))
...
.get();
}This class is immutable and thread-safe.
Appendable,
StringBuilder,
String.join(CharSequence, CharSequence...),
String.join(CharSequence, Iterable),
StringJoiner| Modifier and Type | Class and Description |
|---|---|
static class |
AppendableJoiner.Builder<T>
Builds instances of
AppendableJoiner. |
| Modifier and Type | Method and Description |
|---|---|
static <T> AppendableJoiner.Builder<T> |
builder()
Creates a new builder.
|
StringBuilder |
join(StringBuilder stringBuilder,
Iterable<T> elements)
Joins stringified objects from the given Iterable into a StringBuilder.
|
StringBuilder |
join(StringBuilder stringBuilder,
T... elements)
Joins stringified objects from the given array into a StringBuilder.
|
<A extends Appendable> |
joinA(A appendable,
Iterable<T> elements)
Joins stringified objects from the given Iterable into an Appendable.
|
<A extends Appendable> |
joinA(A appendable,
T... elements)
Joins stringified objects from the given array into an Appendable.
|
public static <T> AppendableJoiner.Builder<T> builder()
T - The type of elements.public StringBuilder join(StringBuilder stringBuilder, Iterable<T> elements)
stringBuilder - The target.elements - The source.public StringBuilder join(StringBuilder stringBuilder, T... elements)
stringBuilder - The target.elements - The source.public <A extends Appendable> A joinA(A appendable, Iterable<T> elements) throws IOException
A - the Appendable type.appendable - The target.elements - The source.IOException - If an I/O error occurspublic <A extends Appendable> A joinA(A appendable, T... elements) throws IOException
A - the Appendable type.appendable - The target.elements - The source.IOException - If an I/O error occursCopyright © 2001–2025 The Apache Software Foundation. All rights reserved.