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

Introduction

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

Source

/*
 * 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.Filter;
import javax.servlet.FilterChain;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

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

import static com.google.inject.servlet.DynamicServletPipeline.DUMMY_INJECTOR;

/**
 * Dynamic {@link FilterPipeline} that can update its sequence of filter definitions on-demand.
 * Includes patched methods from {@link ManagedFilterPipeline} where delegating isn't possible.
 */
@Singleton
// don't use @Named, keep as implicit JIT-binding
final class DynamicFilterPipeline extends ManagedFilterPipeline {
    private final DynamicServletPipeline servletPipeline;

    private final BeanLocator locator;

    // dynamic list of definitions
    private final List<FilterDefinition> filterDefinitions;

    // stable cache of definitions
    private volatile FilterDefinition[] filterDefinitionCache = {};

    private volatile ServletContext servletContext;

    @Inject
    DynamicFilterPipeline(final DynamicServletPipeline servletPipeline, final BeanLocator locator) {
        super(DUMMY_INJECTOR, servletPipeline, null);

        this.servletPipeline = servletPipeline;
        this.locator = locator;

        try {
            // disable lazy init as we don't use it
            super.initPipeline(null /* unused */);
        } catch (final Exception e) {
            throw new IllegalStateException(e);
        }

        filterDefinitions = new EntryListAdapter<>(locator.locate(Key.get(FilterDefinition.class)));
    }

    public ServletContext getServletContext() {
        return servletContext;
    }

    public synchronized void refreshCache() {
        final Object[] snapshot = filterDefinitions.toArray();
        filterDefinitionCache = Arrays.copyOf(snapshot, snapshot.length, FilterDefinition[].class);
        PipelineLogger.dump(filterDefinitionCache);

        servletPipeline.refreshCache();
    }

    @Override
    public synchronized void initPipeline(final ServletContext context) throws ServletException {
        if (servletContext == null && context != null) {
            servletContext = context;

            // register trigger to update definitions as FilterPipeline bindings come and go
            locator.watch(Key.get(FilterPipeline.class), new FilterPipelineMediator(), this);
        }
    }

    @Override
    public void dispatch(ServletRequest request, ServletResponse response, FilterChain proceedingFilterChain)
            throws IOException, ServletException {
        new FilterChainInvocation(filterDefinitions(), servletPipeline, proceedingFilterChain)
                .doFilter(withDispatcher(request, servletPipeline), response);
    }

    @Override
    public void destroyPipeline() {
        servletPipeline.destroy();

        Set<Filter> destroyedSoFar = Sets.newIdentityHashSet();
        for (FilterDefinition filterDefinition : filterDefinitions()) {
            filterDefinition.destroy(destroyedSoFar);
        }
    }

    private static ServletRequest withDispatcher(ServletRequest servletRequest,
            final DynamicServletPipeline servletPipeline) {
        if (!servletPipeline.hasServletsMapped()) {
            return servletRequest;
        }

        return new HttpServletRequestWrapper((HttpServletRequest) servletRequest) {
            @Override
            public RequestDispatcher getRequestDispatcher(String path) {
                final RequestDispatcher dispatcher = servletPipeline.getRequestDispatcher(path);
                return (null != dispatcher) ? dispatcher : super.getRequestDispatcher(path);
            }
        };
    }

    private FilterDefinition[] filterDefinitions() {
        return filterDefinitionCache;
    }
}