com.qiniu.datasource.FilepathReader Maven / Gradle / Ivy

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package com.qiniu.datasource;

import com.qiniu.interfaces.IReader;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class FilepathReader implements IReader> {

    private String name;
    private Iterator iterator;
    private String startLine;
    private int limit;
    private String line;
    private List lineList;
    private long count;

    public FilepathReader(String name, List filepathList, String startLine, int limit) throws IOException {
        if (filepathList == null || filepathList.size() == 0) throw new IOException("invalid filepath list");
        this.name = name;
        this.iterator = filepathList.iterator();
        this.startLine = startLine;
        this.limit = limit;
        this.line = iterator.next();
        this.lineList = filepathList;
        this.count = filepathList.size();
    }

    @Override
    public String getName() {
        return name;
    }

    @Override
    public Iterator getRealReader() {
        return iterator;
    }

    @Override
    public List readLines() {
        if (line == null) {
            return null;
        } else if (count <= limit) {
            line = null;
            if (startLine == null) {
                return lineList;
            } else {
                for (int i = 0; i < lineList.size(); i++) {
                    if (lineList.get(i).compareTo(startLine) > 0) {
                        return lineList.subList(i, lineList.size());
                    }
                }
                return lineList;
            }
        } else {
            List srcList = new ArrayList<>();
            if (startLine == null || line.compareTo(startLine) > 0) {
                srcList.add(line);
            }
            while (true) {
                if (srcList.size() >= limit) break;
                if (iterator.hasNext()) {
                    line = iterator.next();
                    if (startLine == null || line.compareTo(startLine) > 0) {
                        srcList.add(line);
                    }
                } else {
                    line = null;
                    break;
                }
            }
            return srcList;
        }
    }

    @Override
    public String lastLine() {
        return line;
    }

    @Override
    public long count() {
        return count;
    }

    @Override
    public void close() {
        iterator = null;
    }
}