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I see two inefficiencies in your code:

• You call .indexIn() twice in quick succession. You should have saved the return value from the first call.
• You create a substring with each iteration. Starting with Java 7, that would be a performance problem, since each substring is a copy of part of the original string.

Also, it would be no additional work for you to generalize the method to accept any CharSequence.

public static SortedSet<Integer> findWrappingIndices(CharSequence s) {
 SortedSet<Integer> indices = Sets.newTreeSet();
 for (int i = -1; -1 != (i = WRAP_CHAR_MATCHER.indexIn(s, i + 1)); ) {
 indices.add(i); 
 }
 return indices;
}

Another option, using just the built-in Java library, would be to use a regex, with [- ] as the pattern.

I see two inefficiencies in your code:

• You call .indexIn() twice in quick succession. You should have saved the return value from the first call.
• You create a substring with each iteration. Starting with Java 7, that would be a performance problem, since each substring is a copy of part of the original string.

Also, it would be no additional work for you to generalize the method to accept any CharSequence.

public static SortedSet<Integer> findWrappingIndices(CharSequence s) {
 SortedSet<Integer> indices = Sets.newTreeSet();
 for (int i = -1; -1 != (i = WRAP_CHAR_MATCHER.indexIn(s, i + 1)); ) {
 indices.add(i); 
 }
 return indices;
}

Another option, using just the built-in Java library, would be to use a regex, with [- ] as the pattern.

I see two inefficiencies in your code:

• You call .indexIn() twice in quick succession. You should have saved the return value from the first call.
• You create a substring with each iteration. Starting with Java 7, that would be a performance problem, since each substring is a copy of part of the original string.

Also, it would be no additional work for you to generalize the method to accept any CharSequence.

public static SortedSet<Integer> findWrappingIndices(CharSequence s) {
 SortedSet<Integer> indices = Sets.newTreeSet();
 for (int i = -1; -1 != (i = WRAP_CHAR_MATCHER.indexIn(s, i + 1)); ) {
 indices.add(i); 
 }
 return indices;
}

I see two inefficiencies in your code:

• You call .indexIn() twice in quick succession. You should have saved the return value from the first call.
• You create a substring with each iteration. Starting with Java 7, that would be a performance problem, since each substring is a copy of part of the original string.

Also, it would be no additional work for you to generalize the method to accept any CharSequence.

public static SortedSet<Integer> findWrappingIndices(CharSequence s) {
 SortedSet<Integer> indices = Sets.newTreeSet();
 for (int i = -1; -1 != (i = WRAP_CHAR_MATCHER.indexIn(s, i + 1)); ) {
 indices.add(i); 
 }
 return indices;
}

Another option, using just the built-in Java library, would be to use a regex, with [- ] as the pattern.