/*
* Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package jdk.jfr.internal.consumer;
import jdk.jfr.internal.LogLevel;
import jdk.jfr.internal.LogTag;
import jdk.jfr.internal.Logger;
import jdk.jfr.internal.LongMap;
/**
* Holds mapping between a set of keys and their corresponding object.
*
* If the type is a known type, i.e. {@link RecordedThread}, an
* {@link ObjectFactory} can be supplied which will instantiate a typed object.
*/
final class ConstantMap {
private static final int RESOLUTION_FINISHED = 0;
private static final int RESOLUTION_STARTED = 1;
public static final ConstantMap EMPTY = new ConstantMap();
// A temporary placeholder, so objects can
// reference themselves (directly, or indirectly),
// when making a transition from numeric id references
// to normal Java references.
private final static class Reference {
private final long key;
private final ConstantMap pool;
Reference(ConstantMap pool, long key) {
this.pool = pool;
this.key = key;
}
Object resolve() {
return pool.get(key);
}
public String toString() {
return "ref: " + pool.name + "[" + key + "]";
}
}
final ObjectFactory<?> factory;
final String name;
private final LongMap<Object> objects;
private boolean resolving;
private boolean allResolved;
private ConstantMap() {
this(null, "<empty>");
allResolved = true;
}
ConstantMap(ObjectFactory<?> factory, String name) {
this.name = name;
this.objects = new LongMap<>(2);
this.factory = factory;
}
Object get(long id) {
// fast path, all objects in pool resolved
if (allResolved) {
return objects.get(id);
}
// referenced from a pool, deal with this later
if (!resolving) {
return new Reference(this, id);
}
// should ideally always have a value
Object value = objects.get(id);
if (value == null) {
// unless id is 0 which is used to represent null
if (id != 0) {
Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Missing object id=" + id + " in pool " + name + ". All ids should reference an object");
}
return null;
}
// id is resolved (but not the whole pool)
if (objects.isSetId(id, RESOLUTION_FINISHED)) {
return value;
}
// resolving ourself, abort to avoid infinite recursion
if (objects.isSetId(id, RESOLUTION_STARTED)) {
return null;
}
// mark id as STARTED if we should
// come back during object resolution
objects.setId(id, RESOLUTION_STARTED);
// resolve object!
Object resolved = resolve(value);
// mark id as FINISHED
objects.setId(id, RESOLUTION_FINISHED);
// if a factory exists, convert to RecordedThread.
// RecordedClass etc. and store back results
if (factory != null) {
Object factorized = factory.createObject(id, resolved);
objects.put(id, factorized);
return factorized;
} else {
objects.put(id, resolved);
return resolved;
}
}
private static Object resolve(Object o) {
if (o instanceof Reference) {
return resolve(((Reference) o).resolve());
}
if (o != null && o.getClass().isArray()) {
final Object[] array = (Object[]) o;
for (int i = 0; i < array.length; i++) {
Object element = array[i];
array[i] = resolve(element);
}
return array;
}
return o;
}
public void resolve() {
objects.forEachKey(k -> get(k));
}
public void put(long key, Object value) {
objects.put(key, value);
}
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