org.aspectj.util.SoftHashMap Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of aspectjtools Show documentation

AspectJ tools most notably contains the AspectJ compiler (AJC). AJC applies aspects to Java classes during compilation, fully replacing Javac for plain Java classes and also compiling native AspectJ or annotation-based @AspectJ syntax. Furthermore, AJC can weave aspects into existing class files in a post-compile binary weaving step. This library is a superset of AspectJ weaver and hence also of AspectJ runtime.

There is a newer version: 1.9.22.1

Show newest version

/* *******************************************************************
 * Copyright (c) 2017 Contributors
 * All rights reserved.
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Public License v 2.0
 * which accompanies this distribution and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.txt
 * ******************************************************************/package org.aspectj.util;

import java.lang.ref.ReferenceQueue;
import java.lang.ref.SoftReference;
import java.util.AbstractMap;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

public class SoftHashMap extends AbstractMap {
	private Map map;
	private ReferenceQueue rq = new ReferenceQueue();

	public SoftHashMap() {
		this.map = new HashMap<>();
	}

	class SpecialValue extends SoftReference {
		private final K key;

		SpecialValue(K k, V v) {
			super(v, rq);
			this.key = k;
		}
	}

	@SuppressWarnings("unchecked")
	private void processQueue() {
		SpecialValue sv = null;
		while ((sv = (SpecialValue)rq.poll()) != null) {
			map.remove(sv.key);
		}
	}

	@Override
	public V get(Object key) {
		SpecialValue ref = map.get(key);
		if (ref == null) {
			map.remove(key);
			return null;
		}
		V value = ref.get();
		if (value == null) {
			map.remove(ref.key);
			return null;
		}
		return value;
	}

	@Override
	public V put(K k, V v) {
		processQueue();
		SpecialValue sv = new SpecialValue(k, v);
		SpecialValue result = map.put(k, sv);
		return (result == null ? null : result.get());
	}

	@Override
	public java.util.Set> entrySet() {
		if (map.isEmpty()) { return Collections.emptyMap().entrySet(); }
		Map currentContents = new HashMap<>();
		for (Map.Entry entry: map.entrySet()) {
			V currentValueForEntry = entry.getValue().get();
			if (currentValueForEntry != null) {
				currentContents.put(entry.getKey(), currentValueForEntry);
			}
		}
		return currentContents.entrySet();
	}

	@Override
	public void clear() {
		processQueue();
		map.clear();
	}

	@Override
	public int size() {
		processQueue();
		return map.size();
	}

	@Override
	public V remove(Object k) {
		processQueue();
		SpecialValue ref = map.remove(k);
		if (ref == null) {
			return null;
		}
		return ref.get();
	}
}