/**
* Returns a new {@code StyleSpans} object that has the same total length as this StyleSpans and
* style of every span is mapped by the given function. Adjacent style spans whose style mapped to
* the same value are merged into one. As a consequence, the returned StyleSpans might have fewer
* style spans than this StyleSpans.
*
* @param mapper function to calculate new style
* @return StyleSpans with replaced styles.
*/
default StyleSpans<S> mapStyles(UnaryOperator<S> mapper) {
StyleSpansBuilder<S> builder = new StyleSpansBuilder<>(getSpanCount());
for (StyleSpan<S> span : this) {
builder.add(mapper.apply(span.getStyle()), span.getLength());
}
return builder.create();
}
default StyleSpans<S> concat(StyleSpans<S> that) {
if (that.length() == 0) {
return this;
} else if (this.length() == 0) {
return that;
}
int n1 = this.getSpanCount();
int n2 = that.getSpanCount();
StyleSpan<S> myLast = this.getStyleSpan(n1 - 1);
StyleSpan<S> theirFirst = that.getStyleSpan(0);
StyleSpansBuilder<S> builder;
if (Objects.equals(myLast.getStyle(), theirFirst.getStyle())) {
builder = new StyleSpansBuilder<>(n1 + n2 - 1);
for (int i = 0; i < n1 - 1; ++i) {
builder.add(this.getStyleSpan(i));
}
builder.add(myLast.getStyle(), myLast.getLength() + theirFirst.getLength());
for (int i = 1; i < n2; ++i) {
builder.add(that.getStyleSpan(i));
}
} else {
builder = new StyleSpansBuilder<>(n1 + n2);
builder.addAll(this, n1);
builder.addAll(that, n2);
}
return builder.create();
}
default StyleSpans<S> prepend(StyleSpan<S> span) {
if (span.getLength() == 0) {
return this;
} else if (length() == 0) {
return singleton(span);
}
StyleSpan<S> myFirstSpan = getStyleSpan(0);
if (Objects.equals(span.getStyle(), myFirstSpan.getStyle())) {
StyleSpan<S> newFirstSpan =
new StyleSpan<>(span.getStyle(), span.getLength() + myFirstSpan.getLength());
return new UpdatedSpans<>(this, 0, newFirstSpan);
} else {
return new PrependedSpans<>(this, span);
}
}
default StyleSpans<S> append(StyleSpan<S> span) {
if (span.getLength() == 0) {
return this;
} else if (length() == 0) {
return singleton(span);
}
int lastIdx = getSpanCount() - 1;
StyleSpan<S> myLastSpan = getStyleSpan(lastIdx);
if (Objects.equals(myLastSpan.getStyle(), span.getStyle())) {
StyleSpan<S> newLastSpan =
new StyleSpan<>(span.getStyle(), myLastSpan.getLength() + span.getLength());
return new UpdatedSpans<>(this, lastIdx, newLastSpan);
} else {
return new AppendedSpans<>(this, span);
}
}