ScriptingResourceResolverProviderImpl.java

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 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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package org.apache.sling.scripting.core.impl;

import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;

import org.apache.sling.api.resource.LoginException;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.apache.sling.scripting.api.resource.ScriptingResourceResolverProvider;
import org.osgi.framework.Constants;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.http.whiteboard.HttpWhiteboardConstants;
import org.osgi.service.metatype.annotations.AttributeDefinition;
import org.osgi.service.metatype.annotations.Designate;
import org.osgi.service.metatype.annotations.ObjectClassDefinition;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Component(
        service = {ScriptingResourceResolverProvider.class, ServletRequestListener.class},
        property = {
                Constants.SERVICE_DESCRIPTION + "=Apache Sling Scripting Resource Resolver Provider",
                Constants.SERVICE_VENDOR + "=The Apache Software Foundation",
                HttpWhiteboardConstants.HTTP_WHITEBOARD_CONTEXT_SELECT + "=(" + HttpWhiteboardConstants.HTTP_WHITEBOARD_CONTEXT_NAME +
                        "=*)",
                HttpWhiteboardConstants.HTTP_WHITEBOARD_LISTENER + "=true"
        }

)
@Designate(
        ocd = ScriptingResourceResolverProviderImpl.Configuration.class
)
public class ScriptingResourceResolverProviderImpl implements ScriptingResourceResolverProvider, ServletRequestListener {

    private static final Logger LOGGER = LoggerFactory.getLogger(ScriptingResourceResolverProviderImpl.class);

    private final ThreadLocal<ScriptingResourceResolver> perThreadResourceResolver = new ThreadLocal<>();
    private boolean logStackTraceOnResolverClose;

    @Reference
    private ResourceResolverFactory rrf;

    @ObjectClassDefinition(
            name = "Apache Sling Scripting Resource Resolver Provider Configuration",
            description = "The Apache Sling Scripting Resource Resolver Provider can be used by scripting bundles to obtain resource " +
                    "resolvers for solving scripting dependencies."
    )
    @interface Configuration {

        @AttributeDefinition(
                name = "Log the stack trace call for ResourceResolver#close",
                description = "If enabled, all calls to ResourceResolver#close for the request-scoped resource resolvers will be logged " +
                        "with the full stack trace. Don't enable this setting on production systems."
        )
        boolean log_stacktrace_onclose() default false;

    }

    @Override
    public ResourceResolver getRequestScopedResourceResolver() {
        ScriptingResourceResolver threadResolver = perThreadResourceResolver.get();
        if (threadResolver == null) {
            try {
                ResourceResolver delegate = rrf.getServiceResourceResolver(null);
                threadResolver = new ScriptingResourceResolver(logStackTraceOnResolverClose, delegate);
                perThreadResourceResolver.set(threadResolver);
                if (LOGGER.isDebugEnabled()) {
                    LOGGER.debug("Set per thread resource resolver for thread {}.", Thread.currentThread().getId());
                }
            } catch (LoginException e) {
                throw new IllegalStateException("Cannot create per thread resource resolver.", e);
            }
        }
        return threadResolver;
    }

    @Override
    public void requestInitialized(ServletRequestEvent sre) {
        // we don't care about this event; the request scoped resource resolver is created lazily
    }

    @Override
    public void requestDestroyed(ServletRequestEvent sre) {
        ScriptingResourceResolver scriptingResourceResolver = perThreadResourceResolver.get();
        if (scriptingResourceResolver != null) {
            scriptingResourceResolver._close();
            perThreadResourceResolver.remove();
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("Removed per thread resource resolver for thread {}.", Thread.currentThread().getId());
            }
        }

    }

    @Activate
    protected void activate(Configuration configuration) {
        logStackTraceOnResolverClose = configuration.log_stacktrace_onclose();
    }

}