var cluster = require('cluster');
var cpus = require('os').cpus().length;

// メインプロセスの処理
function main() {
    console.log('main start ==================================');

    cluster.on('exit', function(worker, code, signal) {
        console.log('worker exit.', worker.id);

        for (var id in cluster.workers) {
            return;
        }

        // 全workerの処理が終了
        console.log('finish!!');
    });

    cluster.on('fork', function(worker) {
        // workerに送信
        worker.send({ id: worker.id, signal: '処理を開始して' });

        // workerから終了通知を受け取る
        worker.on('message', function(msg) {
            var w = cluster.workers[msg.id];

            w.send({
                id: w.id,
                signal: 'exit'
            });
        });
    });

    for (var i = 0; i < cpus; i++) {
        cluster.fork();
    }
}

if (cluster.isWorker) {
    process.on('message', function(m) {
        // masterから受信

        if (m.signal === 'exit') {
            // masterから終了通知されたらworkerをexit
            return process.exit(0);
        }

        // workerの処理
        console.log('workerだよん');
        process.send({ id: m.id, status: '処理終わったよ' });
    });

    return;
}

main();

setTimeout(function() {
    main();
}, 3000);

main start ==================================
workerだよん                                 
workerだよん                                 
worker exit. 1                               
worker exit. 4                               
workerだよん                                 
worker exit. 2                               
workerだよん                                 
worker exit. 3                               
finish!!                                     
main start ==================================
workerだよん                                 
workerだよん                                 
worker exit. 5                               
worker exit. 5                               
workerだよん                                 
workerだよん                                 
worker exit. 8                               
worker exit. 8                               
workerだよん                                 
workerだよん                                 
worker exit. 7                               
worker exit. 7                               
workerだよん                                 
workerだよん                                 
worker exit. 6                               
finish!!                                     
worker exit. 6                               
finish!!                                     

function User() {
    this.name = undefined;

    Object.seal(this);
}

var user = new User();
user.name = 'まどか'; // セットできる
user.age = 14; // セットできない
                            
console.log(user); // => { name: 'まどか' }

function User(name) {
    this.name = name;

    Object.freeze(this);
}

var user = new User('ほむほむ');
user.name = 'まどか'; // セットできない
user.age = 14; // セットできない
                            
console.log(user); // => { name: 'ほむほむ' }

LineReader.prototype._onStreamData = function(chunk) {
    this.rs.pause();
    this.buf += chunk;

    var self = this;
    (function searchLine() {
        var i = self.buf.indexOf('\n');
        if (i >= 0) {
            var line = self.buf.slice(0, i + 1);
            self.buf = self.buf.slice(i + 1);
            self.emit('line', line, searchLine);
        } else {
            self.rs.resume();
        }
    })();
};

var list = [];

reader.on('line', function(line, callback) {
    list.push(line);

    if (list.length < 100) {
        return callback();
    }
    
    hogehoge(list, function() {
        list = [];
        callback();
    });
});

>db.Hoge.find();
{_id:1, part1:{code:A, name:madoka}, part2:{code:B, name:homura}, part3:{code:A, name:madoka}}
{_id:2, part2:{code:B, name:homura}, part4:{code:C, name:mami}}
{_id:3, part1:{code:B, name:homura}, part2:{code:A, name:madoka}}

> db.Hoge.find().forEach(function(rec){for(field in rec) {var data = rec[field];if(data&&data.code){if(data.code=="A"){print("_id:" + rec._id + " -> " + field + ".code." + data.code)}}}});
_id:1 -> part1.code.A
_id:1 -> part3.code.A
_id:3 -> part2.code.A

実践JS サーバサイド JavaScript 入門/井上 誠一郎

Document Design for Mongodb/著者不明

>db.hoge.find().explain();
{
"cursor" : "BasicCursor",
"nscanned" : 4,
"nscannedObjects" : 4,
"n" : 4,
"millis" : 0,
"nYields" : 0,
"nChunkSkips" : 0,
"isMultiKey" : false,
"indexOnly" : false,
"indexBounds" : {

}
}

>db.hoge.find({"_id":"madoka"}).explain();
{
"cursor" : "BtreeCursor _id_",
"nscanned" : 1,
"nscannedObjects" : 1,
"n" : 1,
"millis" : 56,
"nYields" : 0,
"nChunkSkips" : 0,
"isMultiKey" : false,
"indexOnly" : false,
"indexBounds" : {
"_id" : [
[
"e39d9bfe5c521e2e",
"e39d9bfe5c521e2e"
]
]
}
}

NoSQLデータベースファーストガイド/佐々木 達也

public static void main(String args[]) {
try {
ICsvBeanReader file = new CsvBeanReader(new FileReader(args[0]),
CsvPreference.EXCEL_PREFERENCE);
final String[] header = file.getCSVHeader(true);
SampleBean sample = null;
while ((sample = file.read(SampleBean.class, header,
SampleBean.processors)) != null) {
System.out.println(sample.getId());
System.out.println(sample.getName());
System.out.println(sample.getDate());
}
} catch (Exception e) {
System.out.println(e);
}
}

public class SampleBean {

private String id;
private String name;
aprivate Date date;

public static final CellProcessor[] processors = new CellProcessor[] {
new Unique(new StrMinMax(1,10)),
new StrMinMax(1,30)),
new ParseDateEx("yyyy/MM/dd")
};

public String getId() {
return Id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
}

final Date result = formatter.parse((String) value);
return next.execute(result, context);

Date result = null;
if (value != null && !"".equals((String)value)) {
result = formatter.parse((String) value);
}
return next.execute(result, context);

cache.getSetMethod(resultBean, nameMapping[i], lineResult.get(i).getClass()).invoke(resultBean, lineResult.get(i));

Class resultClass = null;
Object resultObj = lineResult.get(i);
if (resultObj != null) {
resultClass = resultObj.getClass();
}
cache.getSetMethod(resultBean, nameMapping[i], resultClass).invoke(resultBean, resultObj);