public Builder add(Slice slice) {
assert comparator.compare(slice.start(), slice.end()) <= 0;
if (slices.size() > 0
&& comparator.compare(slices.get(slices.size() - 1).end(), slice.start()) > 0)
needsNormalizing = true;
slices.add(slice);
return this;
}
public Slices build() {
if (slices.isEmpty()) return NONE;
if (slices.size() == 1 && slices.get(0) == Slice.ALL) return ALL;
List<Slice> normalized = needsNormalizing ? normalize(slices) : slices;
return new ArrayBackedSlices(comparator, normalized.toArray(new Slice[normalized.size()]));
}
/**
* Given an array of slices (potentially overlapping and in any order) and return an equivalent
* array of non-overlapping slices in clustering order.
*
* @param slices an array of slices. This may be modified by this method.
* @return the smallest possible array of non-overlapping slices in clustering order. If the
* original slices are already non-overlapping and in comparator order, this may or may not
* return the provided slices directly.
*/
private List<Slice> normalize(List<Slice> slices) {
if (slices.size() <= 1) return slices;
Collections.sort(
slices,
new Comparator<Slice>() {
@Override
public int compare(Slice s1, Slice s2) {
int c = comparator.compare(s1.start(), s2.start());
if (c != 0) return c;
return comparator.compare(s1.end(), s2.end());
}
});
List<Slice> slicesCopy = new ArrayList<>(slices.size());
Slice last = slices.get(0);
for (int i = 1; i < slices.size(); i++) {
Slice s2 = slices.get(i);
boolean includesStart = last.includes(comparator, s2.start());
boolean includesFinish = last.includes(comparator, s2.end());
if (includesStart && includesFinish) continue;
if (!includesStart && !includesFinish) {
slicesCopy.add(last);
last = s2;
continue;
}
if (includesStart) {
last = Slice.make(last.start(), s2.end());
continue;
}
assert !includesFinish;
}
slicesCopy.add(last);
return slicesCopy;
}
public String toCQLString(CFMetaData metadata) {
StringBuilder sb = new StringBuilder();
// In CQL, condition are expressed by column, so first group things that way,
// i.e. for each column, we create a list of what each slice contains on that column
int clusteringSize = metadata.clusteringColumns().size();
List<List<ComponentOfSlice>> columnComponents = new ArrayList<>(clusteringSize);
for (int i = 0; i < clusteringSize; i++) {
List<ComponentOfSlice> perSlice = new ArrayList<>();
columnComponents.add(perSlice);
for (int j = 0; j < slices.length; j++) {
ComponentOfSlice c = ComponentOfSlice.fromSlice(i, slices[j]);
if (c != null) perSlice.add(c);
}
}
boolean needAnd = false;
for (int i = 0; i < clusteringSize; i++) {
ColumnDefinition column = metadata.clusteringColumns().get(i);
List<ComponentOfSlice> componentInfo = columnComponents.get(i);
if (componentInfo.isEmpty()) break;
// For a given column, there is only 3 cases that CQL currently generates:
// 1) every slice are EQ with the same value, it's a simple '=' relation.
// 2) every slice are EQ but with different values, it's a IN relation.
// 3) every slice aren't EQ but have the same values, we have inequality relations.
// Note that this doesn't cover everything that ReadCommand can express, but
// as it's all that CQL support for now, we'll ignore other cases (which would then
// display a bogus query but that's not the end of the world).
// TODO: we should improve this at some point.
ComponentOfSlice first = componentInfo.get(0);
if (first.isEQ()) {
if (needAnd) sb.append(" AND ");
needAnd = true;
sb.append(column.name);
Set<ByteBuffer> values = new LinkedHashSet<>();
for (int j = 0; j < componentInfo.size(); j++)
values.add(componentInfo.get(j).startValue);
if (values.size() == 1) {
sb.append(" = ").append(column.type.getString(first.startValue));
} else {
sb.append(" IN (");
int j = 0;
for (ByteBuffer value : values)
sb.append(j++ == 0 ? "" : ", ").append(column.type.getString(value));
sb.append(")");
}
} else {
// As said above, we assume (without checking) that this means all ComponentOfSlice for
// this column
// are the same, so we only bother about the first.
if (first.startValue != null) {
if (needAnd) sb.append(" AND ");
needAnd = true;
sb.append(column.name)
.append(first.startInclusive ? " >= " : " > ")
.append(column.type.getString(first.startValue));
}
if (first.endValue != null) {
if (needAnd) sb.append(" AND ");
needAnd = true;
sb.append(column.name)
.append(first.endInclusive ? " <= " : " < ")
.append(column.type.getString(first.endValue));
}
}
}
return sb.toString();
}
public int size() {
return slices.size();
}