com.scudata.dm.cursor.MergesCursor Maven / Gradle / Ivy
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SPL(Structured Process Language) A programming language specially for structured data computing.
package com.scudata.dm.cursor;
import com.scudata.dm.ComputeStack;
import com.scudata.dm.Context;
import com.scudata.dm.Current;
import com.scudata.dm.Sequence;
import com.scudata.dm.op.Operation;
import com.scudata.expression.Expression;
import com.scudata.util.Variant;
/**
* ????α???????鲢?????γɵ??α?
* ÿ???α??ڵ????ݾ??Ѿ????ض?????ʽ?ź?˳??
* ????α????ʱ?????ض??Ĺ???鲢?????
* c----conj ??·?α????ΰ?????ʽ??????exps???????????
* u----union ?????????????????ظ????ݡ?ͬһ?α??ڵ??????ظ??????ظ???
* i----isect ??·?α?Ĺ?ͬ???ݲ??????
* d----diff ??һ?????У?????????û?е??????
* @author RunQian
*
*/
public class MergesCursor extends ICursor {
/** ??ɶ?·?α?????顣?α????????Ѿ???exps?Ź???(??֧??????????) **/
private ICursor []cursors;
/** ??·?α?ı???ʽ????????˱???ʽ????(??֧??????????)??????????α??Ѿ????ɴ˱???ʽ??????? **/
private Expression[] exps;
/** ?????ʱ??? **/
private Context ctx;
/** ??·?α꣬?α?鲢???? **/
private char type = 'c'; // c:conj u:union i:isect d:diff x:xor
/** ???ݻ????????????·?α?????? **/
private Sequence []tables; // ???ݻ??????????ڻ???????α?
/** ??ǰ???ݸ??ݱ???ʽ?ļ????? **/
private Object [][]values;
/** ??ǰ???????????ڸ??Ի??????????? **/
private int []seqs;
/** ???????е?ǰԪ?أ???С???????????? **/
private int []items; // ???еĵ?ǰԪ?ش?С?????????
/** ??ǰԪ?ص????? **/
private int []ranks; // ??ǰԪ?ص?????0??1??-1??union??isect??diff??xorʹ??
/** ?Ƿ?ȡ????? **/
private boolean isEnd = false;
/** null????Сֵ???????ֵ **/
private boolean isNullMin = true; // null?Ƿ???Сֵ
private Object NULL = this;
private Context []ctxs; // ÿ????????exps???Լ????????ģ?ÿ????ȡ?????ݺ???ѹջ
private Current []currents;
private Expression[][] dupExps;
/**
* ??·?α깹?캯??
* @param cursors ??ɶ?·?α??????
* @param exps ???????ʽ??cursors?е?ÿ????Ա?????ݸñ???ʽ?????Ź???
* @param ctx ?????ı?????
*/
public MergesCursor(ICursor []cursors, Expression[] exps, Context ctx) {
this(cursors, exps, null, ctx);
}
/**
*
* ??·?α깹?캯??
* @param cursors ??ɶ?·?α??????
* @param exps ???????ʽ??cursors?е?ÿ????Ա?????ݸñ???ʽ?????Ź???
* @param opt ?α?鲢????????c??u??i??d?ĸ????????⡣0?????????????????棩
* c----conj ??·?α????ΰ?????ʽ??????exps???????????
* u----union ?????????????????ظ????ݡ?ͬһ?α??ڵ??????ظ??????ظ???
* i----isect ?????α궼?е??????????
* d----diff ??һ?????У?????????û?е??????
* x----xor ?????α????????
* 0 ????????????һ???????档??0????ʾ??????Ϊnullʱ??Ϊ???ֵ??????Ϊ??Сֵ??
* @param ctx ?????ı?????
*/
public MergesCursor(ICursor []cursors, Expression[] exps, String opt, Context ctx) {
this.cursors = cursors;
this.exps = exps;
this.ctx = ctx;
setDataStruct(cursors[0].getDataStruct());
if (opt != null) {
if (opt.indexOf('u') !=-1) {
type = 'u';
} else if (opt.indexOf('i') !=-1) {
type = 'i';
} else if (opt.indexOf('d') !=-1) {
type = 'd';
} else if (opt.indexOf('x') !=-1) {
type = 'x';
}
if (opt.indexOf('0') !=-1) {
isNullMin = false;
}
}
}
// ???м???ʱ??Ҫ?ı???????
// ?̳???????õ??˱???ʽ????Ҫ?????????????½???????ʽ
public void resetContext(Context ctx) {
if (this.ctx != ctx) {
for (ICursor cursor : cursors) {
cursor.resetContext(ctx);
}
exps = Operation.dupExpressions(exps, ctx);
super.resetContext(ctx);
}
}
/**
* ѡ????һ??Ҫ????ȡ?????ݡ???û?????ݿɶ?????false;
* ?ո?ȡ?????ݵ??α꣬?л???ǰ???ݡ??????α껺???е????ݾ?????ȡ?????ٴλ???һ?????ݡ?
* ?ոձ??л??????ݣ???Ա???ʽ?????㡣
* ???ݸ????α굱ǰ???ݶԱ???ʽ?ļ???????????????ѡ????һ??Ҫ??ȡ??????
*
* @return true ??ǰ??????ȡ??????
* false ??ǰ?????ݿ?ȡ
*/
private boolean popTop() {
int []items = this.items;
int count = items.length;
int item = items[0];
Sequence table = tables[item];
// ?ո?ȡ?????ݵ??α꣬???????????ˣ??Ͷ?ȡ?µ????ݡ?
int next = seqs[item] + 1;
if (next > table.length()) {
ComputeStack stack = ctxs[item].getComputeStack();
stack.pop();
table = cursors[item].fuzzyFetch(FETCHCOUNT_M);
if (table == null || table.length() == 0) {
for (int j = 1; j < count; ++j) {
items[j - 1] = items[j];
}
tables[item] = null;
values[item] = null;
items[count - 1] = -1;
return items[0] != -1;
}
currents[item] = new Current(table, 1);
stack.push(currents[item]);
tables[item] = table;
next = 1;
}
// ?л??굱ǰ???ݣ???Ա???ʽ?????㡣
seqs[item] = next;
currents[item].setCurrent(next);
calc(dupExps[item], ctxs[item], values[item]);
// ѡ????һ??Ҫ??ȡ?????ݡ?
topChange(values, items);
return true;
}
/**
* ?ų???·?α??е??ظ????ݡ?
*
* @return ???ؾ??????غ?ȡ?õ?????
*/
private Object popRepeated() {
Sequence []tables = this.tables;
Object [][]values = this.values;
int []seqs = this.seqs;
int []ranks = this.ranks;
int count = tables.length;
Object r = NULL;
for (int i = 0; i < count; ++i) {
if (ranks[i] == 0) {
if (r == NULL) r = tables[i].getMem(seqs[i]);
int next = seqs[i] + 1;
if (next > tables[i].length()) {
ComputeStack stack = ctxs[i].getComputeStack();
stack.pop();
tables[i] = cursors[i].fuzzyFetch(FETCHCOUNT_M);
if (tables[i] != null && tables[i].length() > 0) {
currents[i] = new Current(tables[i], 1);
stack.push(currents[i]);
calc(dupExps[i], ctxs[i], values[i]);
seqs[i] = 1;
} else {
tables[i] = null;
values[i] = null;
ranks[i] = -1;
}
} else {
seqs[i] = next;
currents[i].setCurrent(next);
calc(dupExps[i], ctxs[i], values[i]);
}
}
}
for (int i = 0; i < count; ++i) {
if (ranks[i] != -1) {
ranks[i] = 0;
for (int j = 0; j < i; ++j) {
if (ranks[j] == 0) {
int cmp = compareArrays(values[i], values[j]);
if (cmp < 0) {
ranks[j] = 1;
for (++j; j < i; ++j) {
if (ranks[j] == 0) {
ranks[j] = 1;
}
}
} else if (cmp > 0) {
ranks[i] = 1;
}
break;
}
}
}
}
return r;
}
/**
* ?ų???·?α????????ݡ?
*
* @return ???ؾ??????غ?ȡ?õ?????
*/
private Object popXor() {
Sequence []tables = this.tables;
Object [][]values = this.values;
int []seqs = this.seqs;
int []ranks = this.ranks;
int count = tables.length;
Object r;
while (true) {
r = NULL;
int xorCount = 0;//??Сֵ?ĸ???
for (int i = 0; i < count; ++i) {
if (ranks[i] == 0) {
if (r == NULL)
r = tables[i].getMem(seqs[i]);
xorCount++;
int next = seqs[i] + 1;
if (next > tables[i].length()) {
ComputeStack stack = ctxs[i].getComputeStack();
stack.pop();
tables[i] = cursors[i].fuzzyFetch(FETCHCOUNT_M);
if (tables[i] != null && tables[i].length() > 0) {
currents[i] = new Current(tables[i], 1);
stack.push(currents[i]);
calc(dupExps[i], ctxs[i], values[i]);
seqs[i] = 1;
} else {
tables[i] = null;
values[i] = null;
ranks[i] = -1;
}
} else {
seqs[i] = next;
currents[i].setCurrent(next);
calc(dupExps[i], ctxs[i], values[i]);
}
}
}
if (r == NULL)
return r;
//????????
for (int i = 0; i < count; ++i) {
if (ranks[i] != -1) {
ranks[i] = 0;
for (int j = 0; j < i; ++j) {
if (ranks[j] == 0) {
int cmp = compareArrays(values[i], values[j]);
if (cmp < 0) {
ranks[j] = 1;
for (++j; j < i; ++j) {
if (ranks[j] == 0) {
ranks[j] = 1;
}
}
} else if (cmp > 0) {
ranks[i] = 1;
}
break;
}
}
}
}
//?????Сֵ???ֵĸ????ǵ?????????Է?????
if (xorCount % 2 == 1 )
break;
}
return r;
}
/**
* ѡ????·?α???һ??Ҫ??ȡ?????ݡ???????
*
* @param values ?????α굱ǰ???ݸ??ݱ???ʽ?ļ?????
* @param items ?????α굱ǰ???ݣ??ڻ??????е?????
*/
private void topChange(Object [][]values, int []items) {
int item = items[0];
Object []obj = values[item];
if (items[1] == -1 || compareArrays(obj, values[items[1]]) <= 0) {
return;
}
int low = 2;
int high = values.length - 1;
while (low <= high) {
int mid = (low + high) >> 1;
if (items[mid] == -1) {
high = mid - 1;
} else {
int cmp = compareArrays(obj, values[items[mid]]);
if (cmp < 0) {
high = mid - 1;
} else if (cmp > 0) {
low = mid + 1;
} else {
System.arraycopy(items, 1, items, 0, mid - 1);
items[mid - 1] = item;
return; // key found
}
}
}
// key not found
System.arraycopy(items, 1, items, 0, low - 1);
items[low - 1] = item;
}
private static void calc(Expression []exps, Context ctx, Object []outValues) {
for (int i = 0, len = exps.length; i < len; ++i) {
outValues[i] = exps[i].calculate(ctx);
}
}
/**
* ???????α?Ļ?????????????????????????ֱ?ӷ??ء?
*/
private void getData() {
if (tables != null) return;
ICursor []cursors = this.cursors;
Expression[] exps = this.exps;
Context ctx = this.ctx;
int tcount = cursors.length;
tables = new Sequence[tcount];
values = new Object[tcount][];
seqs = new int[tcount];
ctxs = new Context[tcount];
currents = new Current[tcount];
dupExps = new Expression[tcount][];
if (type == 'c') {
items = new int[tcount]; // ???еĵ?ǰԪ?ش?С?????????
for (int i = 0; i < tcount; ++i) {
ctxs[i] = ctx.newComputeContext();
dupExps[i] = Operation.dupExpressions(exps, ctxs[i]);
Sequence table = cursors[i].fuzzyFetch(FETCHCOUNT_M);
if (table != null && table.length() > 0) {
Object []curValues = new Object[exps.length];
currents[i] = new Current(table, 1);
ctxs[i].getComputeStack().push(currents[i]);
calc(dupExps[i], ctxs[i], curValues);
tables[i] = table;
values[i] = curValues;
seqs[i] = 1;
items[i] = i;
for (int j = 0; j < i; ++j) {
if (items[j] == -1) {
items[j] = i;
items[i] = -1;
break;
} else if (compareArrays(curValues, values[items[j]]) < 0) {
for (int k = i; k > j; --k) {
items[k] = items[k - 1];
}
items[j] = i;
break;
}
}
} else {
items[i] = -1;
}
}
} else {
ranks = new int[tcount]; // ???еĵ?ǰԪ?ص?????
for (int i = 0; i < tcount; ++i) {
ctxs[i] = ctx.newComputeContext();
dupExps[i] = Operation.dupExpressions(exps, ctxs[i]);
Sequence table = cursors[i].fuzzyFetch(FETCHCOUNT_M);
if (table != null && table.length() > 0) {
Object []curValues = new Object[exps.length];
currents[i] = new Current(table, 1);
ctxs[i].getComputeStack().push(currents[i]);
calc(dupExps[i], ctxs[i], curValues);
tables[i] = table;
values[i] = curValues;
seqs[i] = 1;
ranks[i] = 0;
for (int j = 0; j < i; ++j) {
if (ranks[j] == 0) {
int cmp = compareArrays(curValues, values[j]);
if (cmp < 0) {
ranks[j] = 1;
for (++j; j < i; ++j) {
if (ranks[j] == 0) {
ranks[j] = 1;
}
}
} else if (cmp > 0) {
ranks[i] = 1;
}
break;
}
}
} else {
ranks[i] = -1;
}
}
}
}
/**
* uid????ģʽ?µ?ȡ??
*
* @param n Ҫȡ????????
* @return ????ȡ?????
*/
private Sequence get_uid(int n) {
Sequence table;
if (n > INITSIZE) {
table = new Sequence(INITSIZE);
} else {
table = new Sequence(n);
}
if (type == 'u') { // u--unionȥ?غϲ???·?α?????
for (int i = 0; i < n; ++i) {
// ????ȥ??ȡ?????????ų??ظ?????
Object r = popRepeated();
if (r != NULL) {
table.add(r);
} else {
break;
}
}
} else if (type == 'i') { // i--isect???????·?α?Ĺ?ͬ????
int []ranks = this.ranks;
int tcount = tables.length;
Next:
for (; n != 0;) {
for (int t = 0; t < tcount; ++t) {
if (ranks[t] != 0) {
if (popRepeated() == NULL) {
break Next;
} else {
continue Next;
}
}
}
Object r = popRepeated();
table.add(r);
--n;
}
} else if (type == 'x') { // x--xor?????·?α????????Ľ??
for (int i = 0; i < n; ++i) {
Object r = popXor();
if (r != NULL) {
table.add(r);
} else {
break;
}
}
} else { // d--diff ???????һ·?α???е?????
int []ranks = this.ranks;
int tcount = tables.length;
Next:
for (; n != 0;) {
if (ranks[0] == 1) {
if (popRepeated() == NULL) {
break Next;
} else {
continue Next;
}
} else if (ranks[0] == -1) {
break Next;
}
for (int t = 1; t < tcount; ++t) {
if (ranks[t] == 0) {
popRepeated();
continue Next;
}
}
Object r = popRepeated();
table.add(r);
--n;
}
}
if (table.length() == 0) {
return null;
} else {
return table;
}
}
private long skip_uid(long n) {
if (type == 'u') {
for (long i = 0; i < n; ++i) {
Object r = popRepeated();
if (r == NULL) {
return i;
}
}
} else if (type == 'i') {
int []ranks = this.ranks;
int tcount = tables.length;
Next:
for (long i = 0; i < n;) {
for (int t = 0; t < tcount; ++t) {
if (ranks[t] != 0) {
if (popRepeated() == NULL) {
return i;
} else {
continue Next;
}
}
}
popRepeated();
++i;
}
} else { // 'd'
int []ranks = this.ranks;
int tcount = tables.length;
Next:
for (long i = 0; i < n;) {
if (ranks[0] == 1) {
if (popRepeated() == NULL) {
return i;
} else {
continue Next;
}
} else if (ranks[0] == -1) {
return i;
}
for (int t = 1; t < tcount; ++t) {
if (ranks[t] == 0) {
popRepeated();
continue Next;
}
}
popRepeated();
++i;
}
}
return n;
}
/**
* ȡ??ָ????????????
* ??????????????????ж???ȡ???١?
* uid????ȡ????ʽ????get_ui????ʵ?֡?
* ??????????Ҫ????Ϊc??ʽ??ȡ?????̡????????У???????ķ?ʽȡ?????ݡ?
* @param n Ҫȡ????????
*/
protected Sequence get(int n) {
if (isEnd || n < 1) return null;
try {
// ??仺????
getData();
// uid????ģʽ?µ?ȡ??
if (type != 'c') return get_uid(n);
int []items = this.items;
if (items[0] == -1) {
return null;
}
// ?????????ݻ?????
Sequence []tables = this.tables;
int []seqs = this.seqs;
Sequence table;
if (n > INITSIZE) {
table = new Sequence(INITSIZE);
} else {
table = new Sequence(n);
}
// ѭ??ȡ??????仺??????ѭ???????жԸ?·?α??ȡ???????????鲢??
for (int i = 0; i < n; ++i) {
int item = items[0];
Object r = tables[item].getMem(seqs[item]);
table.add(r);
if (!popTop()) {
break;
}
}
return table;
} catch (RuntimeException e) {
close();
throw e;
}
}
/**
* ????ָ????????????
* @param n ????
* @return long ʵ????????????
*/
protected long skipOver(long n) {
if (isEnd || n < 1) return 0;
try {
getData();
if (type != 'c') return skip_uid(n);
int []items = this.items;
if (items[0] == -1) {
return 0;
}
for (long i = 0; i < n; ++i) {
if (!popTop()) {
return i + 1;
}
}
return n;
} catch (RuntimeException e) {
close();
throw e;
}
}
/**
* ?ر??α?
*/
public synchronized void close() {
super.close();
if (cursors != null) {
for (int i = 0, count = cursors.length; i < count; ++i) {
cursors[i].close();
}
tables = null;
values = null;
seqs = null;
items = null;
isEnd = true;
}
}
/**
* ?????α?
* @return ?????Ƿ?ɹ???true???α???Դ?ͷ????ȡ????false???????Դ?ͷ????ȡ??
*/
public boolean reset() {
close();
for (int i = 0, count = cursors.length; i < count; ++i) {
if (!cursors[i].reset()) {
return false;
}
}
isEnd = false;
return true;
}
/**
* ??·?α??ڶԱ????????ݵĴ?С
* ????isNullMin????ͬ?ıȽ?
*/
private int compareArrays(Object []o1, Object []o2) {
if (isNullMin) {
return Variant.compareArrays(o1, o2);
} else {
return Variant.compareArrays_0(o1, o2);
}
}
}