com.google.inject.servlet.DynamicServletPipeline.java Source code

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Here is the source code for com.google.inject.servlet.DynamicServletPipeline.java

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/*
 * Sonatype Nexus (TM) Open Source Version
 * Copyright (c) 2008-present Sonatype, Inc.
 * All rights reserved. Includes the third-party code listed at http://links.sonatype.com/products/nexus/oss/attributions.
 *
 * This program and the accompanying materials are made available under the terms of the Eclipse Public License Version 1.0,
 * which accompanies this distribution and is available at http://www.eclipse.org/legal/epl-v10.html.
 *
 * Sonatype Nexus (TM) Professional Version is available from Sonatype, Inc. "Sonatype" and "Sonatype Nexus" are trademarks
 * of Sonatype, Inc. Apache Maven is a trademark of the Apache Software Foundation. M2eclipse is a trademark of the
 * Eclipse Foundation. All other trademarks are the property of their respective owners.
 */
package com.google.inject.servlet;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Set;

import javax.inject.Inject;
import javax.inject.Singleton;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

import com.google.common.collect.Sets;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Key;
import org.eclipse.sisu.inject.BeanLocator;
import org.eclipse.sisu.wire.EntryListAdapter;

import static com.google.common.base.Preconditions.checkState;

/**
 * Dynamic {@code ServletPipeline} that can update its sequence of servlet definitions on-demand.
 * Includes patched methods from {@link ManagedServletPipeline} where delegating isn't possible.
 */
@Singleton
// don't use @Named, keep as implicit JIT-binding
final class DynamicServletPipeline extends ManagedServletPipeline {
    static final Injector DUMMY_INJECTOR = Guice.createInjector();

    // dynamic list of definitions
    private final List<ServletDefinition> servletDefinitions;

    // stable cache of definitions
    private volatile ServletDefinition[] servletDefinitionCache = {};

    @Inject
    DynamicServletPipeline(final BeanLocator locator) {
        super(DUMMY_INJECTOR);

        servletDefinitions = new EntryListAdapter<>(locator.locate(Key.get(ServletDefinition.class)));
    }

    public synchronized void refreshCache() {
        final Object[] snapshot = servletDefinitions.toArray();
        servletDefinitionCache = Arrays.copyOf(snapshot, snapshot.length, ServletDefinition[].class);
        PipelineLogger.dump(servletDefinitionCache);
    }

    @Override
    public boolean service(ServletRequest request, ServletResponse response) throws IOException, ServletException {
        for (ServletDefinition servletDefinition : servletDefinitions()) {
            if (servletDefinition.service(request, response)) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void destroy() {
        Set<HttpServlet> destroyedSoFar = Sets.newIdentityHashSet();
        for (ServletDefinition servletDefinition : servletDefinitions()) {
            servletDefinition.destroy(destroyedSoFar);
        }
    }

    @Override
    RequestDispatcher getRequestDispatcher(final String path) {
        for (final ServletDefinition servletDefinition : servletDefinitions()) {
            if (servletDefinition.shouldServe(path)) {
                return new RequestDispatcher() {
                    public void forward(ServletRequest servletRequest, ServletResponse servletResponse)
                            throws ServletException, IOException {
                        checkState(!servletResponse.isCommitted(),
                                "Response has been committed--you can only call forward before"
                                        + " committing the response (hint: don't flush buffers)");

                        servletResponse.resetBuffer();

                        ServletRequest requestToProcess = servletRequest instanceof HttpServletRequest
                                ? wrapRequest((HttpServletRequest) servletRequest, path)
                                : servletRequest;

                        doServiceImpl(requestToProcess, servletResponse);
                    }

                    public void include(ServletRequest servletRequest, ServletResponse servletResponse)
                            throws ServletException, IOException {
                        doServiceImpl(servletRequest, servletResponse);
                    }

                    private void doServiceImpl(ServletRequest servletRequest, ServletResponse servletResponse)
                            throws ServletException, IOException {
                        servletRequest.setAttribute(REQUEST_DISPATCHER_REQUEST, Boolean.TRUE);
                        try {
                            servletDefinition.doService(servletRequest, servletResponse);
                        } finally {
                            servletRequest.removeAttribute(REQUEST_DISPATCHER_REQUEST);
                        }
                    }
                };
            }
        }

        return null;
    }

    @Override
    protected boolean hasServletsMapped() {
        return servletDefinitionCache.length > 0;
    }

    private ServletDefinition[] servletDefinitions() {
        return servletDefinitionCache;
    }
}