jIPC

Inter-Process Communication based on SharedMemory (mmaped-file) for Java. Open Source Java project under Apache License v2.0

Current Stable Version is 1.0.1

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MAVEN

Add the dependency to your pom.xml:

<dependency>
    <groupId>org.javastack</groupId>
    <artifactId>jipc</artifactId>
    <version>1.0.1</version>
</dependency>

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DOC

Usage Example

import java.nio.charset.Charset;

import org.javastack.jipc.Msg;
import org.javastack.jipc.jIPC;

public class HelloWorld {
	private static final Charset Latin1 = Charset.forName("ISO-8859-1");

	public static void main(final String[] args) throws Throwable {
		final jIPC ipc = new jIPC("/tmp/ipc.tmp").open();
		if (ipc.isEmpty()) {
			ipc.put("hello world".getBytes(Latin1));
		} else {
			final Msg msg = ipc.get();
			System.out.println("msg=" + msg);
			System.out.println("data=" + new String(msg.data, Latin1));
		}
		ipc.close();
	}
}

• More examples in Example package

Internal Memory Structure (SharedMem)

Header (offset 0):

magic	lock	msgType	msgId	dataLen
4bytes	4bytes	4bytes	4bytes	4bytes

Data (offset 4096):

data
VarLen

IF: data-len = -1 (no data)

Notes:

• Offsets are relative to 0

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Benchmarks

Values are not accurate, but orientative. Higher better. All test Running on Laptop { Windows 7 (64bits), Core i5-3337U 1.8Ghz, 8GB Ram }.

useUnsafe	duplex	jvm	msg/s
false	true	32bits	167000
false	true	64bits	169000
false	false	32bits	196000
false	false	64bits	202000
true	true	32bits	801000
true	true	64bits	1109000
true	false	32bits	1381000
true	false	64bits	1703000

Note about sun.misc.Unsafe

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Inspired in System V Shared memory and clip-library, this code is Java-minimalistic version.