+package org.simantics.scl.ui.editor2.iterator;
+
+import java.text.CharacterIterator;
+
+import org.eclipse.core.runtime.Assert;
+
+
+
+/**
+ * A <code>CharSequence</code> based implementation of <code>CharacterIterator</code>.
+ *
+ * @since 3.0
+ */
+public class SequenceCharacterIterator implements CharacterIterator {
+
+ private int fIndex= -1;
+ private final CharSequence fSequence;
+ private final int fFirst;
+ private final int fLast;
+
+ private void invariant() {
+ Assert.isTrue(fIndex >= fFirst);
+ Assert.isTrue(fIndex <= fLast);
+ }
+
+ /**
+ * Creates an iterator for the entire sequence.
+ *
+ * @param sequence the sequence backing this iterator
+ */
+ public SequenceCharacterIterator(CharSequence sequence) {
+ this(sequence, 0);
+ }
+
+ /**
+ * Creates an iterator.
+ *
+ * @param sequence the sequence backing this iterator
+ * @param first the first character to consider
+ * @throws IllegalArgumentException if the indices are out of bounds
+ */
+ public SequenceCharacterIterator(CharSequence sequence, int first) throws IllegalArgumentException {
+ this(sequence, first, sequence.length());
+ }
+
+ /**
+ * Creates an iterator.
+ *
+ * @param sequence the sequence backing this iterator
+ * @param first the first character to consider
+ * @param last the last character index to consider
+ * @throws IllegalArgumentException if the indices are out of bounds
+ */
+ public SequenceCharacterIterator(CharSequence sequence, int first, int last) throws IllegalArgumentException {
+ if (sequence == null)
+ throw new NullPointerException();
+ if (first < 0 || first > last)
+ throw new IllegalArgumentException();
+ if (last > sequence.length())
+ throw new IllegalArgumentException();
+ fSequence= sequence;
+ fFirst= first;
+ fLast= last;
+ fIndex= first;
+ invariant();
+ }
+
+ /*
+ * @see java.text.CharacterIterator#first()
+ */
+ public char first() {
+ return setIndex(getBeginIndex());
+ }
+
+ /*
+ * @see java.text.CharacterIterator#last()
+ */
+ public char last() {
+ if (fFirst == fLast)
+ return setIndex(getEndIndex());
+ else
+ return setIndex(getEndIndex() - 1);
+ }
+
+ /*
+ * @see java.text.CharacterIterator#current()
+ */
+ public char current() {
+ if (fIndex >= fFirst && fIndex < fLast)
+ return fSequence.charAt(fIndex);
+ else
+ return DONE;
+ }
+
+ /*
+ * @see java.text.CharacterIterator#next()
+ */
+ public char next() {
+ return setIndex(Math.min(fIndex + 1, getEndIndex()));
+ }
+
+ /*
+ * @see java.text.CharacterIterator#previous()
+ */
+ public char previous() {
+ if (fIndex > getBeginIndex()) {
+ return setIndex(fIndex - 1);
+ } else {
+ return DONE;
+ }
+ }
+
+ /*
+ * @see java.text.CharacterIterator#setIndex(int)
+ */
+ public char setIndex(int position) {
+ if (position >= getBeginIndex() && position <= getEndIndex())
+ fIndex= position;
+ else
+ throw new IllegalArgumentException();
+
+ invariant();
+ return current();
+ }
+
+ /*
+ * @see java.text.CharacterIterator#getBeginIndex()
+ */
+ public int getBeginIndex() {
+ return fFirst;
+ }
+
+ /*
+ * @see java.text.CharacterIterator#getEndIndex()
+ */
+ public int getEndIndex() {
+ return fLast;
+ }
+
+ /*
+ * @see java.text.CharacterIterator#getIndex()
+ */
+ public int getIndex() {
+ return fIndex;
+ }
+
+ /*
+ * @see java.text.CharacterIterator#clone()
+ */
+ @Override
+ public Object clone() {
+ try {
+ return super.clone();
+ } catch (CloneNotSupportedException e) {
+ throw new InternalError();
+ }
+ }
+}