import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
@Override
public void visit(OpSlice opSlice) {
    SqlOp subOp = stack.pop();
    // change order of tree nodes
    if(subOp instanceof SqlProject){
    	SqlSlice slice = new SqlSlice(opSlice, ((SqlProject) subOp).getSubOp(), prefixes);
    	SqlProject project = new SqlProject(((SqlProject) subOp).getOpProject(), (SqlOp)slice, prefixes);
    	stack.push(project);
    } else {
    stack.push(new SqlSlice(opSlice, subOp, prefixes));
    }
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
@Override
public void visit(OpSlice opSlice) {
	ImpalaOp subOp = stack.pop();
	// change order of tree nodes
	if(subOp instanceof ImpalaProject){
		ImpalaSlice slice = new ImpalaSlice(opSlice, ((ImpalaProject) subOp).getSubOp(), prefixes);
		ImpalaProject project = new ImpalaProject(((ImpalaProject) subOp).getOpProject(), slice, prefixes);
		stack.push(project);
	} else {
		stack.push(new ImpalaSlice(opSlice, subOp, prefixes));
	}
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
public SparkSlice(OpSlice op) {
this.op = op;
   }
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
@Override
   public void visit(OpSlice opSlice) {
executionQueue.add(new SparkSlice(opSlice));
   }
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
public SqlSlice(OpSlice _opSlice, SqlOp _subOp,
		PrefixMapping _prefixes) {
	super(_subOp, _prefixes);
	opSlice = _opSlice;
	resultName = Tags.SLICE;
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
public PigSlice(OpSlice _opSlice, PigOp _subOp, PrefixMapping _prefixes) {
    super(_subOp, _prefixes);
    opSlice = _opSlice;
    resultName = Tags.SLICE;
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
public ImpalaSlice(OpSlice _opSlice, ImpalaOp _subOp,
		PrefixMapping _prefixes) {
	super(_subOp, _prefixes);
	opSlice = _opSlice;
	resultName = Tags.SLICE;
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
public void visit(OpSlice opSlice) {
	wrapInCurrentFilterAndRecurse(opSlice);
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
@Override
public Op transform(OpSlice opSlice, Op subOp) {
	return substitute(opSlice, subOp);
}
 

import com.hp.hpl.jena.sparql.algebra.op.OpSlice; //导入依赖的package包/类
@Override
public Op transform(OpSlice opSlice, Op subOp) {
	return subOp;
}