/** 如果是1 = id的情况，转化为id = 1 */
private static IFilter exchage(IFilter root) {
IBooleanFilter bf = (IBooleanFilter) root;
if (!FilterUtils.isConstValue(bf.getValue()) && FilterUtils.isConstValue(bf.getColumn())) {
Object val = bf.getColumn();
bf.setColumn(bf.getValue());
bf.setValue(val);
OPERATION newOp = bf.getOperation();
switch (bf.getOperation()) {
case GT:
newOp = OPERATION.LT;
break;
case LT:
newOp = OPERATION.GT;
break;
case GT_EQ:
newOp = OPERATION.LT_EQ;
break;
case LT_EQ:
newOp = OPERATION.GT_EQ;
break;
default:
break;
}
bf.setOperation(newOp);
}
return bf;
}
/** 将0=1/1=1/true的恒等式进行优化 */
private static IFilter shortestFilter(IFilter root) throws EmptyResultFilterException {
IFilter filter = FilterUtils.toDNFAndFlat(root);
List<List<IFilter>> DNFfilter = FilterUtils.toDNFNodesArray(filter);
List<List<IFilter>> newDNFfilter = new ArrayList<List<IFilter>>();
for (List<IFilter> andDNFfilter : DNFfilter) {
boolean isShortest = false;
List<IFilter> newAndDNFfilter = new ArrayList<IFilter>();
for (IFilter one : andDNFfilter) {
if (one.getOperation() == OPERATION.CONSTANT) {
boolean flag = false;
if (((IBooleanFilter) one).getColumn() instanceof ISelectable) { // 可能是个not函数
newAndDNFfilter.add(one); // 不能丢弃
} else {
String value = ((IBooleanFilter) one).getColumn().toString();
if (StringUtils.isNumeric(value)) {
flag = BooleanUtils.toBoolean(Integer.valueOf(value));
} else {
flag = BooleanUtils.toBoolean(((IBooleanFilter) one).getColumn().toString());
}
if (!flag) {
isShortest = true;
break;
}
}
} else {
newAndDNFfilter.add(one);
}
}
if (!isShortest) {
if (newAndDNFfilter.isEmpty()) {
// 代表出现为true or xxx，直接返回true
IBooleanFilter f = ASTNodeFactory.getInstance().createBooleanFilter();
f.setOperation(OPERATION.CONSTANT);
f.setColumn("1");
f.setColumnName(ObjectUtils.toString("1"));
return f;
} else { // 针对非false的情况
newDNFfilter.add(newAndDNFfilter);
}
}
}
if (newDNFfilter.isEmpty()) {
throw new EmptyResultFilterException("空结果");
}
return FilterUtils.DNFToOrLogicTree(newDNFfilter);
}
private static IFilter processFilter(IFilter root) {
if (root == null) {
return null;
}
root = shortestFilter(root); // 短路一下
root = processOneFilter(root); // 做一下转换处理
root = FilterUtils.merge(root); // 合并一下flter
return root;
}
private static IFilter typeConvert(IFilter root) {
IBooleanFilter bf = (IBooleanFilter) root;
// 如果是id in (xx)
if (bf.getValues() != null && bf.getColumn() instanceof ISelectable) {
for (int i = 0; i < bf.getValues().size(); i++) {
bf.getValues()
.set(
i,
OptimizerUtils.convertType(
bf.getValues().get(i), ((ISelectable) bf.getColumn()).getDataType()));
}
} else {
// 如果是 1 = id情况
if (FilterUtils.isConstValue(bf.getColumn()) && !FilterUtils.isConstValue(bf.getValue())) {
DATA_TYPE type = null;
if (bf.getValue() instanceof IColumn) {
type = ((IColumn) bf.getValue()).getDataType();
}
if (bf.getValue() instanceof IFunction) {
type = ((IFunction) bf.getValue()).getDataType();
}
bf.setColumn(OptimizerUtils.convertType(bf.getColumn(), type));
}
// 如果是 id = 1情况
if (FilterUtils.isConstValue(bf.getValue()) && !FilterUtils.isConstValue(bf.getColumn())) {
DATA_TYPE type = null;
if (bf.getColumn() instanceof IColumn) {
type = ((IColumn) bf.getColumn()).getDataType();
}
if (bf.getColumn() instanceof IFunction) {
type = ((IFunction) bf.getColumn()).getDataType();
}
bf.setValue(OptimizerUtils.convertType(bf.getValue(), type));
}
}
return bf;
}
private List<IFilter> toDNFFilter(IFilter where) {
return FilterUtils.toDNFNodesArray(where).get(0);
}
