@Override
Value getMergedValue(Database database, int dataType, boolean distinct) {
if (distinct) {
count = 0;
groupDistinct(database, dataType);
}
Value v = null;
switch (aggregateType) {
case Aggregate.SUM:
case Aggregate.MIN:
case Aggregate.MAX:
case Aggregate.BOOL_AND:
case Aggregate.BOOL_OR:
case Aggregate.BIT_AND:
case Aggregate.BIT_OR:
v = value;
break;
case Aggregate.AVG:
case Aggregate.STDDEV_POP:
case Aggregate.STDDEV_SAMP:
case Aggregate.VAR_POP:
case Aggregate.VAR_SAMP:
default:
DbException.throwInternalError("type=" + aggregateType);
}
return v == null ? ValueNull.INSTANCE : v.convertTo(dataType);
}
@Override
Value getValue(Database database, int dataType, boolean distinct) {
if (distinct) {
count = 0;
groupDistinct(database, dataType);
}
Value v = null;
switch (aggregateType) {
case Aggregate.SUM:
case Aggregate.MIN:
case Aggregate.MAX:
case Aggregate.BIT_OR:
case Aggregate.BIT_AND:
case Aggregate.BOOL_OR:
case Aggregate.BOOL_AND:
v = value;
break;
case Aggregate.AVG:
if (value != null) {
v = Aggregate.divide(value, count);
}
break;
case Aggregate.STDDEV_POP:
{
if (count < 1) {
return ValueNull.INSTANCE;
}
v = ValueDouble.get(Math.sqrt(m2 / count));
break;
}
case Aggregate.STDDEV_SAMP:
{
if (count < 2) {
return ValueNull.INSTANCE;
}
v = ValueDouble.get(Math.sqrt(m2 / (count - 1)));
break;
}
case Aggregate.VAR_POP:
{
if (count < 1) {
return ValueNull.INSTANCE;
}
v = ValueDouble.get(m2 / count);
break;
}
case Aggregate.VAR_SAMP:
{
if (count < 2) {
return ValueNull.INSTANCE;
}
v = ValueDouble.get(m2 / (count - 1));
break;
}
default:
DbException.throwInternalError("type=" + aggregateType);
}
return v == null ? ValueNull.INSTANCE : v.convertTo(dataType);
}
@Override
void add(Database database, int dataType, boolean distinct, Value v) {
if (v == ValueNull.INSTANCE) {
return;
}
count++;
if (distinct) {
if (distinctValues == null) {
distinctValues = ValueHashMap.newInstance();
}
distinctValues.put(v, this);
return;
}
switch (aggregateType) {
case Aggregate.SUM:
if (value == null) {
value = v.convertTo(dataType);
} else {
v = v.convertTo(value.getType());
value = value.add(v);
}
break;
case Aggregate.AVG:
if (value == null) {
value = v.convertTo(DataType.getAddProofType(dataType));
} else {
v = v.convertTo(value.getType());
value = value.add(v);
}
break;
case Aggregate.MIN:
if (value == null || database.compare(v, value) < 0) {
value = v;
}
break;
case Aggregate.MAX:
if (value == null || database.compare(v, value) > 0) {
value = v;
}
break;
case Aggregate.STDDEV_POP:
case Aggregate.STDDEV_SAMP:
case Aggregate.VAR_POP:
case Aggregate.VAR_SAMP:
{
// Using Welford's method, see also
// http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
// http://www.johndcook.com/standard_deviation.html
double x = v.getDouble();
if (count == 1) {
mean = x;
m2 = 0;
} else {
double delta = x - mean;
mean += delta / count;
m2 += delta * (x - mean);
}
break;
}
case Aggregate.BOOL_AND:
v = v.convertTo(Value.BOOLEAN);
if (value == null) {
value = v;
} else {
value =
ValueBoolean.get(value.getBoolean().booleanValue() && v.getBoolean().booleanValue());
}
break;
case Aggregate.BOOL_OR:
v = v.convertTo(Value.BOOLEAN);
if (value == null) {
value = v;
} else {
value =
ValueBoolean.get(value.getBoolean().booleanValue() || v.getBoolean().booleanValue());
}
break;
case Aggregate.BIT_AND:
if (value == null) {
value = v.convertTo(dataType);
} else {
value = ValueLong.get(value.getLong() & v.getLong()).convertTo(dataType);
}
break;
case Aggregate.BIT_OR:
if (value == null) {
value = v.convertTo(dataType);
} else {
value = ValueLong.get(value.getLong() | v.getLong()).convertTo(dataType);
}
break;
default:
DbException.throwInternalError("type=" + aggregateType);
}
}
@Override
void merge(Database database, int dataType, boolean distinct, Value v) {
if (v == ValueNull.INSTANCE) {
return;
}
count++;
if (distinct) {
if (distinctValues == null) {
distinctValues = ValueHashMap.newInstance();
}
distinctValues.put(v, this);
return;
}
switch (aggregateType) {
case Aggregate.SUM:
if (value == null) {
value = v.convertTo(dataType);
} else {
v = v.convertTo(value.getType());
value = value.add(v);
}
break;
case Aggregate.MIN:
if (value == null || database.compare(v, value) < 0) {
value = v;
}
break;
case Aggregate.MAX:
if (value == null || database.compare(v, value) > 0) {
value = v;
}
break;
case Aggregate.BOOL_AND:
v = v.convertTo(Value.BOOLEAN);
if (value == null) {
value = v;
} else {
value =
ValueBoolean.get(value.getBoolean().booleanValue() && v.getBoolean().booleanValue());
}
break;
case Aggregate.BOOL_OR:
v = v.convertTo(Value.BOOLEAN);
if (value == null) {
value = v;
} else {
value =
ValueBoolean.get(value.getBoolean().booleanValue() || v.getBoolean().booleanValue());
}
break;
case Aggregate.BIT_AND:
if (value == null) {
value = v.convertTo(dataType);
} else {
value = ValueLong.get(value.getLong() & v.getLong()).convertTo(dataType);
}
break;
case Aggregate.BIT_OR:
if (value == null) {
value = v.convertTo(dataType);
} else {
value = ValueLong.get(value.getLong() | v.getLong()).convertTo(dataType);
}
break;
// 这5个在分布式环境下会进行重写，所以合并时是不会出现的
case Aggregate.AVG:
case Aggregate.STDDEV_POP:
case Aggregate.STDDEV_SAMP:
case Aggregate.VAR_POP:
case Aggregate.VAR_SAMP:
default:
DbException.throwInternalError("type=" + aggregateType);
}
}