servi/org.eclipse.statet.rj.servi/srcServiPool/org/eclipse/statet/internal/rj/servi/APool2NodeHandler.java

/*=============================================================================#
 # Copyright (c) 2009, 2020 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.internal.rj.servi;

import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.server.Unreferenced;

import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.impl.DefaultPooledObject;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;

import org.eclipse.statet.rj.RjException;
import org.eclipse.statet.rj.servi.pool.PoolNodeObject;
import org.eclipse.statet.rj.servi.pool.PoolNodeState;


@NonNullByDefault
public class APool2NodeHandler extends NodeHandler implements PoolNodeObject,
		RServiImpl.PoolRef, Unreferenced {
	
	
	static final long safeNanos(final long nanos) {
		return (nanos != 0) ? nanos : 1;
	}
	
	static final long evictNanos(final long timeoutMillis) {
		long nanos= System.nanoTime();
		if (timeoutMillis > 0) {
			nanos+= timeoutMillis * 1_000_000L;
		}
		return safeNanos(nanos);
	}
	
	
	private final APool2 pool;
	private final DefaultPooledObject<APool2NodeHandler> p;
	private volatile long evict;
	
	final Stats.NodeEntry stats= new Stats.NodeEntry();
	
	@Nullable Remote thisRemote;
	
	private volatile long accessId;
	
	
	public APool2NodeHandler(final APool2 pool) {
		this.pool= pool;
		this.p= new DefaultPooledObject<>(this);
	}
	
	
	@Override
	public NodeHandler getNodeHandler() {
		return this;
	}
	
	PooledObject<APool2NodeHandler> getPooledObject() {
		return this.p;
	}
	
	@Override
	public long getCreationTime() {
		return this.p.getCreateTime();
	}
	
	@Override
	public long getAllocatedCount() {
		return this.p.getBorrowedCount();
	}
	
	@Override
	public long getAllocatedDuration() {
		return this.p.getActiveTimeMillis();
	}
	
	@Override
	public PoolNodeState getState() {
		if (this.node == null) {
			switch (this.p.getState()) {
			case IDLE:
				return PoolNodeState.INITIALIZING;
			case INVALID:
				return PoolNodeState.DISPOSED;
			default:
				break;
			}
		}
		
		switch(this.p.getState()) {
		case IDLE:
			return PoolNodeState.IDLING;
		case ALLOCATED:
			return PoolNodeState.ALLOCATED;
		default:
			return PoolNodeState.CHECKING;
		}
	}
	
	@Override
	public long getStateTime() {
		switch (getState()) {
		case INITIALIZING:
			return getStartTime();
		case ALLOCATED:
			return this.p.getLastBorrowTime();
		case CHECKING:
		case IDLING:
			return this.p.getLastReturnTime();
		case DISPOSED:
			return getShutdownTime();
		default:
			return -1;
		}
	}
	
	
	@Override
	void bindClient(final String name, final String host) throws RemoteException {
		super.bindClient(name, host);
		synchronized (this) {
			this.accessId= this.p.getBorrowedCount();
		}
	}
	
	void invalidateClient() {
		this.accessId= -1L;
		setClientLabel(null);
	}
	
	@Override
	void unbindClient() throws RemoteException {
		synchronized (this) {
			invalidateClient();
		}
		super.unbindClient();
	}
	
	@Override
	public void evict(final long timeout) {
		doEvict(evictNanos(timeout), timeout == 0);
	}
	
	void doEvict(final long nanos, final boolean direct) {
		synchronized (this.p) {
			if (this.evict == 0 || this.evict > nanos) {
				this.evict= safeNanos(nanos);
			}
		}
		
		if (direct) {
			try {
				this.pool.invalidateObject(this);
			}
			catch (final Exception e) {}
		}
	}
	
	boolean isEvictRequested(final long nanos) {
		final long evict= this.evict;
		return (evict != 0
				&& (nanos == 0 || nanos >= evict) );
	}
	
	long getAccessId() {
		final long accessId= this.accessId;
		if (accessId == -1L) {
			throw new IllegalAccessError();
		}
		return accessId;
	}
	
	@Override
	public void returnObject(final long accessId) throws RjException {
		try {
			synchronized (this) {
				if (this.accessId != accessId) {
					throw new IllegalStateException("Access id no longer valid.");
				}
				invalidateClient();
			}
			this.pool.returnObject(this);
		}
		catch (final Exception e) {
			Utils.logError("An unexpected error occurred when returning RServi instance.", e);
			throw new RjException("An unexpected error occurred when closing RServi instance. See server log for detail.");
		}
	}
	
	@Override
	public void unreferenced() {
		final PoolNodeState state= getState();
		synchronized (this) {
			if (state != PoolNodeState.ALLOCATED || this.accessId == -1L) {
				return;
			}
			invalidateClient();
		}
		Utils.logInfo("The RServi instance is lent and unreferenced. It will be returned now.");
		try {
			this.pool.returnObject(this);
		}
		catch (final Exception e) {
			Utils.logError("An unexpected error occurred when returning RServi instance.", e);
		}
	}
	
}