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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.BaseRecord;
import com.scudata.dm.ComputeStack;
import com.scudata.dm.Context;
import com.scudata.dm.Current;
import com.scudata.dm.DataStruct;
import com.scudata.dm.Sequence;
import com.scudata.dm.Table;
import com.scudata.dm.op.Operation;
import com.scudata.expression.Expression;
import com.scudata.expression.Node;
import com.scudata.util.Variant;
/**
* ????????α꣬?α???????Ѱ??????ֶ???????ʱֻ??????ڵļ?¼?ȽϷ????ֶ??Ƿ???ͬ
* ????????ʵ???????麯??cs.groupx()?Ķ??η??飬??????????ʱ?????????????ֶ?????д??????ʱ?ļ???
* ?ٶ???ʱ?ļ????????ֶι鲢?γ??????α?
* @author RunQian
*
*/
public class GroupmCursor extends ICursor {
private ICursor cursor; // ???ݰ??????ֶ???????α?
private Expression []exps; // ???????ʽ
private Expression []newExps; // ???ܱ???ʽ
private Node []gathers; // ???ܱ???ʽ??Ӧ?Ļ??ܺ???
private DataStruct newDs; // ????????ݽṹ
private Sequence data; // ???α???ȡ????????
private int currentIndex; // ??ǰҪ????????ݵ????
/**
* ????????????α?
* @param cursor ???ݰ??????ֶ???????α?
* @param exps ???????ʽ????
* @param names ?????ֶ???????
* @param newExps ???ܱ???ʽ????
* @param newNames ?????ֶ???????
* @param ctx ??????????
*/
public GroupmCursor(ICursor cursor, Expression[] exps, String []names,
Expression[] newExps, String []newNames, Context ctx) {
this.cursor = cursor;
this.exps = exps;
this.newExps = newExps;
this.ctx = ctx;
int count = exps.length;
int newCount = newExps == null ? 0 : newExps.length;
// ???ʡ???˽?????ֶ??????ݱ???ʽ?Զ?????
if (names == null) {
names = new String[count];
}
for (int i = 0; i < count; ++i) {
if (names[i] == null || names[i].length() == 0) {
names[i] = exps[i].getFieldName();
}
}
if (newNames == null) {
newNames = new String[newCount];
}
for (int i = 0; i < newCount; ++i) {
if (newNames[i] == null || newNames[i].length() == 0) {
newNames[i] = newExps[i].getFieldName();
}
}
String []totalNames = new String[count + newCount];
System.arraycopy(names, 0, totalNames, 0, count);
System.arraycopy(newNames, 0, totalNames, count, newCount);
newDs = new DataStruct(totalNames);
newDs.setPrimary(names);
gathers = Sequence.prepareGatherMethods(newExps, ctx);
setDataStruct(newDs);
}
// ???м???ʱ??Ҫ?ı???????
// ?̳???????õ??˱???ʽ????Ҫ?????????????½???????ʽ
public void resetContext(Context ctx) {
if (this.ctx != ctx) {
cursor.resetContext(ctx);
exps = Operation.dupExpressions(exps, ctx);
newExps = Operation.dupExpressions(newExps, ctx);
gathers = Sequence.prepareGatherMethods(newExps, ctx);
super.resetContext(ctx);
}
}
private Sequence getData() {
if (data != null) {
return data;
}
data = cursor.fetch(FETCHCOUNT);
if (data == null || data.length() == 0) {
return null;
} else {
currentIndex = 1;
return data;
}
}
/**
* ??ȡָ???????????ݷ???
* @param n ????
* @return Sequence
*/
protected Sequence get(int n) {
if (cursor == null || n < 1) {
return null;
}
Sequence data = getData();
if (data == null) {
return null;
}
Table newTable;
if (n > INITSIZE) {
newTable = new Table(newDs, INITSIZE);
} else {
newTable = new Table(newDs, n);
}
Context ctx = this.ctx;
Expression[] exps = this.exps;
Node []gathers = this.gathers;
int keyCount = exps.length;
int valCount = gathers == null ? 0 : gathers.length;
Object []keys = new Object[keyCount];
Object []nextKeys = new Object[keyCount];
int index = currentIndex;
ComputeStack stack = ctx.getComputeStack();
Current current = new Current(data);
stack.push(current);
current.setCurrent(index++);
try {
for (int k = 0; k < keyCount; ++k) {
keys[k] = exps[k].calculate(ctx);
}
BaseRecord cur = newTable.newLast(keys);
for (int v = 0, f = keyCount; v < valCount; ++v, ++f) {
Object val = gathers[v].gather(ctx);
cur.setNormalFieldValue(f, val);
}
End:
while (true) {
for (int len = data.length(); index <= len; ++index) {
current.setCurrent(index);
for (int k = 0; k < keyCount; ++k) {
nextKeys[k] = exps[k].calculate(ctx);
}
if (Variant.compareArrays(keys, nextKeys) == 0) {
for (int v = 0, f = keyCount; v < valCount; ++v, ++f) {
Object val = gathers[v].gather(cur.getNormalFieldValue(f), ctx);
cur.setNormalFieldValue(f, val);
}
} else {
if (newTable.length() == n) {
this.currentIndex = index;
break End;
}
Object []tmp = keys;
keys = nextKeys;
nextKeys = tmp;
cur = newTable.newLast(keys);
for (int v = 0, f = keyCount; v < valCount; ++v, ++f) {
Object val = gathers[v].gather(ctx);
cur.setNormalFieldValue(f, val);
}
}
}
this.data = null;
data = getData();
if (data == null) break;
index = 1;
stack.pop();
current = new Current(data);
stack.push(current);
}
} finally {
stack.pop();
}
newTable.finishGather(gathers);
return newTable;
}
/**
* ????ָ????????????
* @param n ????
* @return long ʵ????????????
*/
protected long skipOver(long n) {
if (cursor == null || n < 1) return 0;
Sequence data = getData();
if (data == null) return 0;
Context ctx = this.ctx;
Expression[] exps = this.exps;
int keyCount = exps.length;
Object []keys = new Object[keyCount];
Object []nextKeys = new Object[keyCount];
long count = 1;
int index = currentIndex;
ComputeStack stack = ctx.getComputeStack();
Current current = new Current(data);
stack.push(current);
current.setCurrent(index++);
try {
for (int k = 0; k < keyCount; ++k) {
keys[k] = exps[k].calculate(ctx);
}
End:
while (true) {
for (int len = data.length(); index <= len; ++index) {
current.setCurrent(index);
for (int k = 0; k < keyCount; ++k) {
nextKeys[k] = exps[k].calculate(ctx);
}
if (Variant.compareArrays(keys, nextKeys) != 0) {
if (count == n) {
this.currentIndex = index;
break End;
}
Object []tmp = keys;
keys = nextKeys;
nextKeys = tmp;
count++;
}
}
this.data = null;
data = getData();
if (data == null) break;
index = 1;
stack.pop();
current = new Current(data);
stack.push(current);
}
} finally {
stack.pop();
}
return count;
}
/**
* ?ر??α?
*/
public synchronized void close() {
super.close();
if (cursor != null) {
cursor.close();
cursor = null;
exps = null;
gathers = null;
newDs = null;
data = null;
}
}
}