com.scudata.dm.op.FetchResult Maven / Gradle / Ivy

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SPL(Structured Process Language) A programming language specially for structured data computing.

There is a newer version: 20240823

package com.scudata.dm.op;

import com.scudata.dm.Context;
import com.scudata.dm.FileObject;
import com.scudata.dm.Sequence;

/**
 * ???ڱ??ֹܵ???ǰ??????Ϊ?????
 * @author RunQian
 *
 */
public class FetchResult implements IResult {
	private Sequence result;
	private FilePipe filePipe;
	
	public FetchResult() {
		result = new Sequence();
	}
	
	public FetchResult(FileObject fo) {
		filePipe = new FilePipe(fo);
	}
	
	/**
	 * ?????α??ܵ???ǰ???͵?????
	 * @param seq ????
	 * @param ctx ??????????
	 * @return
	 */
	public void push(Sequence table, Context ctx) {
		if (result != null) {
			result.addAll(table);
		} else {
			filePipe.push(table, ctx);
		}
	}
	
	/**
	 * ???????ͽ???ʱ????
	 * @param ctx ??????????
	 */
	public void finish(Context ctx) {
		if (filePipe != null) {
			filePipe.close();
		}
	}
	
	 /**
	  * ???????ͽ?????ȡ???յļ?????
	  * @return ???
	  */
	public Object result() {
		Sequence seq = result;
		if (seq == null || seq.length() == 0) {
			return null;
		}
		
		result = null;
		return seq;
	}
	
	/**
	 * ??Ⱥ?ܵ??????Ҫ?Ѹ??ڵ???ķ??ؽ???ٺϲ?һ??
	 * @param results ÿ???ڵ???ļ?????
	 * @return ?ϲ???Ľ??
	 */
	public Object combineResult(Object []results) {
		int count = results.length;
		Sequence result = new Sequence();
		for (int i = 0; i < count; ++i) {
			if (results[i] instanceof Sequence) {
				result.addAll((Sequence)results[i]);
			} else if (results[i] != null) {
				result.add(results[i]);
			}
		}

		return result;
	}
}