ggrandes/memoizer

Agnostic Cache in Java. If you call the function again with the same arguments, memoize return value out from cache, instead of compute again.

memoizer

Agnostic Cache with Dynamic Proxies and Reflection in Java. Open Source Java project under Apache License v2.0, do not require any external lib.

Memoize a function makes it faster by caching the return values of the function; If you call the function again with the same arguments, memoize gives you the value out of the cache, instead of letting the function compute the value all over again.

Current Stable Version is 1.0.0

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DOC

Usage Example

import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import javax.xml.bind.DatatypeConverter;

import org.javastack.memoizer.Memoizer;

public class Example {
	/**
	 * Sample Interface to Memoize
	 */
	public static interface SampleInterface {
		public String hash(final String in) throws NoSuchAlgorithmException;
	}

	/**
	 * Sample Slow Implementation (MessageDigest with SHA-512)
	 */
	public static class SampleSlowImpl implements SampleInterface {
		private static final Charset UTF8 = Charset.forName("UTF-8");

		public String hash(final String in) throws NoSuchAlgorithmException {
			final MessageDigest md = MessageDigest.getInstance("SHA-512");
			final byte[] buf = md.digest(in.getBytes(UTF8));
			return DatatypeConverter.printBase64Binary(buf);
		}
	}

	public static void main(final String[] args) throws Throwable {
		final int TOTAL = (int) 1e6;
		final String TEST_TEXT = "hello world";
		//
		final SampleInterface slowCode = new SampleSlowImpl();
		final int cacheElements = 1024;
		final long cacheMillis = 1000; // 1 second
		final SampleInterface fast = (SampleInterface) Memoizer.memoize(
				slowCode, 
				cacheElements, 
				cacheMillis);
		//
		final long ts = System.currentTimeMillis();
		for (int i = 0; i < TOTAL; i++) {
			fast.hash(TEST_TEXT);
		}
		final long diff = System.currentTimeMillis() - ts;
		System.out.println("diff=" + diff + "ms" + "\t" + //
				fast.hash(TEST_TEXT));
	}
}

• Full examples in Example package

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MAVEN

Add the dependency to your pom.xml:

<dependency>
    <groupId>org.javastack</groupId>
    <artifactId>memoizer</artifactId>
    <version>1.0.0</version>
</dependency>

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Inspired in Perl Memoize, this code is Java-minimalistic version.