package com.taobao.tddl.executor.cursor.impl;
import java.util.Comparator;
import java.util.List;
import com.taobao.tddl.common.exception.TddlException;
import com.taobao.tddl.common.utils.GeneralUtil;
import com.taobao.tddl.executor.common.KVPair;
import com.taobao.tddl.executor.cursor.IRangeCursor;
import com.taobao.tddl.executor.cursor.ISchematicCursor;
import com.taobao.tddl.executor.cursor.RangeMaker;
import com.taobao.tddl.executor.cursor.SchematicCursor;
import com.taobao.tddl.executor.record.CloneableRecord;
import com.taobao.tddl.executor.rowset.IRowSet;
import com.taobao.tddl.executor.utils.ExecUtils;
import com.taobao.tddl.optimizer.config.table.ColumnMeta;
import com.taobao.tddl.optimizer.core.expression.IFilter;
import com.taobao.tddl.optimizer.core.expression.IOrderBy;
import com.taobao.tddl.optimizer.core.expression.ISelectable;
import com.taobao.tddl.common.utils.logger.Logger;
import com.taobao.tddl.common.utils.logger.LoggerFactory;
/**
* 现在具有对多个索引内前缀字段+非前缀字段
*
* @author jianxing <jianxing.qx@taobao.com>
*/
public class RangeCursor extends SchematicCursor implements IRangeCursor {
public static final Logger log = LoggerFactory.getLogger(RangeCursor.class);
/**
* 范围，到哪里结束
*/
protected IRowSet to;
/**
* 范围，从哪里开始？
*/
protected IRowSet from;
protected Comparator<IRowSet> fromComparator;
protected Comparator<IRowSet> toComparator;
private boolean schemaInited = false;
private IFilter lf = null;
boolean first = true;
public RangeCursor(ISchematicCursor cursor, IFilter lf){
super(cursor, null, cursor.getOrderBy());
this.lf = lf;
RangeMaker.Range range = makeRange(lf, orderBys);
this.from = range.from;
this.to = range.to;
}
protected RangeMaker.Range makeRange(IFilter lf, List<IOrderBy> orderBys) {
return new RangeMaker().makeRange(lf, orderBys);
}
private void initSchema(IRowSet firstRowSet, IFilter lf) {
if (schemaInited) {
return;
}
schemaInited = true;
List<ColumnMeta> columnMetas = to.getParentCursorMeta().getColumns();
List<ISelectable> iColumns = ExecUtils.getIColumnsWithISelectable(columnMetas.toArray(new ColumnMeta[0]));
toComparator = ExecUtils.getComp(iColumns,
iColumns,
to.getParentCursorMeta(),
firstRowSet.getParentCursorMeta());
fromComparator = ExecUtils.getComp(iColumns,
iColumns,
from.getParentCursorMeta(),
firstRowSet.getParentCursorMeta());
// init(rangeFilters);
}
@Override
public IRowSet next() throws TddlException {
if (cursor == null) {
return null;
}
IRowSet kv = null;
if (!first) {
kv = cursor.next();
} else {
first = false;
kv = first();
if (kv == null) {
return null;
}
}
if (kv == null) {
return null;
}
if (match(kv)) {
return kv;
} else {
return null;
}
}
/**
* @param kv
* @return true 如果符合区间。false 如果不符合区间
*/
private boolean match(IRowSet kv) {
initSchema(kv, lf);
int res = fromComparator.compare(from, kv);
if (res == 0) {// eq;
return true;
} else if (res > 0) {
return false;
}
res = toComparator.compare(to, kv);
if (res == 0) {
return true;
} else if (res < 0) {
return false;
}
return true;
}
@Override
public boolean skipTo(CloneableRecord key) throws TddlException {
if (parentCursorSkipTo(key)) {
IRowSet kv = current();
if (match(kv)) {
return true;
}
}
return false;
}
@Override
public boolean skipTo(KVPair key) throws TddlException {
return skipTo(key.getKey());
}
@Override
public IRowSet first() throws TddlException {
this.first = false;
IRowSet iRowSet = from;
CloneableRecord cr = ExecUtils.convertToClonableRecord(iRowSet);
if (!cursor.skipTo(cr)) {
return null;
} else {
return cursor.current();
}
}
@Override
public IRowSet last() throws TddlException {
first = false;
IRowSet iRowSet = to;
CloneableRecord cr = ExecUtils.convertToClonableRecord(iRowSet);
// to在数据中间有四种可能
// data:5,6,7,8,9,10,15
// case1: to是data的某个值，如9
// case2: to大于最大值，如17
// case3: to小于最小值，如2
// case4: to在某两个值之间，如11
// case5: data为空
if (!cursor.skipTo(cr)) { // case2: to大于最大值，如17
IRowSet last = cursor.last();
if (last == null) {// case5: data为空
return null;
}
if (match(last)) {
// 只考虑to，是肯定匹配的，不匹配的可能是from
return last;
} else {
return null;
}
} else {
if (match(cursor.current())) { // case1: to是data的某个值，如9
// 此时current和to相等
return cursor.current();
}// current>to或者current<from
// 取prev的值
// 如果current<from，则prev同样小于from，不会match
else {
IRowSet prevCurrent = cursor.prev();
if (prevCurrent == null) { // case3: to小于最小值，如2
return null;
} else { // case4: to在某两个值之间，如11
if (match(prevCurrent)) {
return prevCurrent;
} else {
return null;
}
}
}
}
}
@Override
public IRowSet prev() throws TddlException {
IRowSet kv;
if (!first) {
kv = parentCursorPrev();
} else {
first = false;
kv = last();
if (kv == null) {
return null;
}
}
if (kv == null) {
return null;
}
if (match(kv)) {
return kv;
} else {
return null;
}
}
@Override
public String toString() {
return toStringWithInden(0);
}
public String toStringWithInden(int inden) {
StringBuilder sb = new StringBuilder();
String tab = GeneralUtil.getTab(inden);
sb.append(tab)
.append("【Range cursor .start : ")
.append(from)
.append("|")
.append(" end : ")
.append(to)
.append("\n");
ExecUtils.printOrderBy(orderBys, inden, sb);
sb.append(super.toStringWithInden(inden));
return sb.toString();
}
@Override
public void beforeFirst() throws TddlException {
this.first = true;
}
public IRowSet getTo() {
return to;
}
public void setTo(IRowSet to) {
this.to = to;
}
public IRowSet getFrom() {
return from;
}
public void setFrom(IRowSet from) {
this.from = from;
}
}