org.echocat.jomon.resources.optimizing.OptimizationContextFactory Maven / Gradle / Ivy

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/*****************************************************************************************
 * *** BEGIN LICENSE BLOCK *****
 *
 * Version: MPL 2.0
 *
 * echocat Jomon, Copyright (c) 2012-2014 echocat
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * *** END LICENSE BLOCK *****
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package org.echocat.jomon.resources.optimizing;

import org.echocat.jomon.resources.PathBasedResourceProvider;
import org.echocat.jomon.resources.Resource;
import org.echocat.jomon.resources.ResourceRequestUriGenerator;
import org.echocat.jomon.resources.optimizing.OptimizationContext.Feature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;
import java.util.*;
import java.util.Map.Entry;

import static com.google.common.collect.Iterables.isEmpty;
import static java.lang.Boolean.TRUE;
import static java.util.Arrays.asList;
import static java.util.Collections.singletonList;
import static java.util.Collections.synchronizedMap;
import static java.util.Collections.unmodifiableSet;

public class OptimizationContextFactory {

    private static final Logger LOG = LoggerFactory.getLogger(OptimizationContextFactory.class);

    private final ResourcesOptimizer _optimizer;
    private final PathBasedResourceProvider _resourceProvider;
    private final ResourceRequestUriGenerator _resourceRequestUriGenerator;

    public OptimizationContextFactory(@Nonnull ResourcesOptimizer optimizer, @Nonnull PathBasedResourceProvider resourceProvider, @Nonnull ResourceRequestUriGenerator resourceRequestUriGenerator) {
        _optimizer = optimizer;
        _resourceProvider = resourceProvider;
        _resourceRequestUriGenerator = resourceRequestUriGenerator;
    }

    @Nonnull
    public OptimizationContext create(@Nullable Feature... withFeatures) {
        return create(withFeatures != null ? asList(withFeatures) : null);
    }

    @Nonnull
    public OptimizationContext create(@Nullable Iterable withFeatures) {
        final OptimizationContextImpl context = new OptimizationContextImpl();
        if (withFeatures != null) {
            for (final Feature withFeature : withFeatures) {
                if (withFeature != null) {
                    context.setFeature(withFeature, true);
                }
            }
        }
        return context;
    }

    @ThreadSafe
    protected class OptimizationContextImpl implements OptimizationContext {

        private final Map _features = synchronizedMap(new HashMap());

        @Override
        public boolean isFeatureEnabled(@Nonnull Feature feature) {
            return TRUE.equals(_features.get(feature));
        }

        @Override
        public void setFeature(@Nonnull Feature feature, boolean enabled) {
            _features.put(feature, enabled);
        }

        @Override
        @Nonnull
        public Set getFeatures() {
            final Set features = new HashSet<>();
            synchronized (_features) {
                for (final Entry entry : _features.entrySet()) {
                    if (TRUE.equals(entry.getValue())) {
                        features.add(entry.getKey());
                    }
                }
            }
            return unmodifiableSet(features);
        }

        @Nonnull
        @Override
        public Resource optimize(@Nonnull Resource input) throws Exception {
            final Collection outputs = optimize(singletonList(input));
            final Resource output;
            if (isEmpty(outputs)) {
                LOG.warn("This resource " + input + " could not be optimized by " + _optimizer + ". The optimizer returned no results. This will return the original one. This could cause other problems but we hope that this will help. Check the configuration of you optimizers to prevent this problem in the future.");
                output = input;
            } else if (outputs.size() == 1) {
                output = outputs.iterator().next();
            } else {
                LOG.warn("This resource " + input + " could not be optimized by " + _optimizer + ". The optimizer returned " + outputs.size() + " results. This will return the original one. This could cause other problems but we hope that this will help. Check the configuration of you optimizers to prevent this problem in the future.");
                output = input;
            }
            return output;
        }

        @Nonnull
        @Override
        public Collection optimize(@Nonnull Collection inputs) throws Exception {
            final Collection optimized = _optimizer.optimize(inputs, this);
            for (final Resource resource : optimized) {
                resource.touch();
            }
            return optimized;
        }

        @Override
        @Nullable
        public Resource findAndOptimizeFor(@Nonnull String uri) throws Exception {
            final Resource unoptimized = _resourceProvider.findBy(uri);
            final Resource optimized;
            if (unoptimized != null) {
                optimized = optimize(unoptimized);
            } else {
                optimized = null;
            }
            return optimized;
        }

        @Override
        @Nullable
        public String findOptimizeAndReturnUriFor(@Nonnull String uri) throws Exception {
            final Resource optimized = findAndOptimizeFor(uri);
            return optimized != null ? _resourceRequestUriGenerator.generate(optimized) : null;
        }
    }

}