Content of file PathAwareEntityFinderDelegate.java.html
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" lang="en"><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/><link rel="stylesheet" href="../../jacoco-resources/report.css" type="text/css"/><link rel="shortcut icon" href="../../jacoco-resources/report.gif" type="image/gif"/><title>PathAwareEntityFinderDelegate.java</title><link rel="stylesheet" href="../../jacoco-resources/prettify.css" type="text/css"/><script type="text/javascript" src="../../jacoco-resources/prettify.js"></script></head><body onload="window['PR_TAB_WIDTH']=4;prettyPrint()"><div class="breadcrumb" id="breadcrumb"><span class="info"><a href="../../jacoco-sessions.html" class="el_session">Sessions</a></span><a href="../../index.html" class="el_report">blueMarine II :: Media Scanner</a> > <a href="../index.html" class="el_bundle">it-tidalwave-bluemarine2-model</a> > <a href="index.source.html" class="el_package">it.tidalwave.bluemarine2.model.impl</a> > <span class="el_source">PathAwareEntityFinderDelegate.java</span></div><h1>PathAwareEntityFinderDelegate.java</h1><pre class="source lang-java linenums">/*
* *********************************************************************************************************************
*
* blueMarine II: Semantic Media Centre
* http://tidalwave.it/projects/bluemarine2
*
* Copyright (C) 2015 - 2021 by Tidalwave s.a.s. (http://tidalwave.it)
*
* *********************************************************************************************************************
*
* Licensed 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 limitations under the License.
*
* *********************************************************************************************************************
*
* git clone https://bitbucket.org/tidalwave/bluemarine2-src
* git clone https://github.com/tidalwave-it/bluemarine2-src
*
* *********************************************************************************************************************
*/
package it.tidalwave.bluemarine2.model.impl;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.Collection;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.function.Function;
import java.nio.file.Path;
import it.tidalwave.util.As;
import it.tidalwave.util.Finder;
import it.tidalwave.util.SupplierBasedFinder;
import it.tidalwave.util.spi.FinderSupport;
import it.tidalwave.role.SimpleComposite;
import it.tidalwave.bluemarine2.model.MediaFolder;
import it.tidalwave.bluemarine2.model.spi.PathAwareEntity;
import it.tidalwave.bluemarine2.model.spi.PathAwareFinder;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import static java.util.Collections.singletonList;
import static it.tidalwave.role.SimpleComposite._SimpleComposite_;
import static lombok.AccessLevel.PRIVATE;
/***********************************************************************************************************************
*
* A decorator of an {@link Finder} of {@link PathAwareEntity} that creates a virtual tree of entities. Each entity is
* given a path, which starts with the path of a {@link MediaFolder} and continues with the id of the entity.
*
* This {@code Finder} can filtered by path. If a filter path is provided, the filtering happens in memory: this means
* that even when the delegate queries a native store, all the data are first retrieved in memory.
*
* @stereotype Finder
*
* @author Fabrizio Giudici
*
**********************************************************************************************************************/
<span class="fc" id="L65">@RequiredArgsConstructor(access = PRIVATE) @Slf4j</span>
public class PathAwareEntityFinderDelegate extends FinderSupport<PathAwareEntity, PathAwareFinder> implements PathAwareFinder
{
private static final long serialVersionUID = 4429676480224742813L;
@Nonnull
private final MediaFolder mediaFolder;
@Nonnull
private final Finder<PathAwareEntity> delegate;
@Nonnull
private final Optional<Path> optionalPath;
/*******************************************************************************************************************
*
* Creates an instance associated to a given {@link MediaFolder} and a delegate finder.
*
* @see #PathAwareEntityFinderDelegate(it.tidalwave.bluemarine2.model.MediaFolder, java.util.function.Function)
*
* @param mediaFolder the folder associated to this finder
* @param delegate the delegate finder to provide data
*
******************************************************************************************************************/
public PathAwareEntityFinderDelegate (@Nonnull final MediaFolder mediaFolder,
@Nonnull final Finder<PathAwareEntity> delegate)
{
<span class="nc" id="L92"> this(mediaFolder, delegate, Optional.empty());</span>
<span class="nc" id="L93"> }</span>
/*******************************************************************************************************************
*
* Creates an instance associated to a given {@link MediaFolder} and a function for providing children. This
* constructor is typically used when the children are already present in memory (e.g. they are
* {@link VirtualMediaFolder}s. Because the function doesn't have the full semantics of a {@link Finder} - it can't
* optimise a query in function of search parameters, nor optimise the count of results - when a
* {@code PathAwareEntityFinderDelegate} is created in this way all operations will be performed in memory. If one
* can provide data from a native store and enjoy optimised queries, instead of this constructor use
* {@link #PathAwareEntityFinderDelegate(it.tidalwave.bluemarine2.model.MediaFolder, it.tidalwave.util.Finder)}
*
* @see #PathAwareEntityFinderDelegate(it.tidalwave.bluemarine2.model.MediaFolder, it.tidalwave.util.Finder)
*
* @param mediaFolder the folder associated to this finder
* @param function the function that provides children
*
******************************************************************************************************************/
public PathAwareEntityFinderDelegate (@Nonnull final MediaFolder mediaFolder,
@Nonnull final Function<MediaFolder, Collection<? extends PathAwareEntity>> function)
{
<span class="fc" id="L114"> this(mediaFolder, new SupplierBasedFinder<>(() -> function.apply(mediaFolder)), Optional.empty());</span>
<span class="fc" id="L115"> }</span>
/*******************************************************************************************************************
*
* Clone constructor.
*
******************************************************************************************************************/
public PathAwareEntityFinderDelegate (@Nonnull final PathAwareEntityFinderDelegate other,
@Nonnull final Object override)
{
<span class="fc" id="L125"> super(other, override);</span>
<span class="fc" id="L126"> final PathAwareEntityFinderDelegate source = getSource(PathAwareEntityFinderDelegate.class, other, override);</span>
<span class="fc" id="L127"> this.mediaFolder = source.mediaFolder;</span>
<span class="fc" id="L128"> this.delegate = source.delegate;</span>
<span class="fc" id="L129"> this.optionalPath = source.optionalPath;</span>
<span class="fc" id="L130"> }</span>
/*******************************************************************************************************************
*
* {@inheritDoc}
*
******************************************************************************************************************/
@Override @Nonnull
public PathAwareFinder withPath (@Nonnull final Path path)
{
<span class="fc" id="L140"> return clonedWith(new PathAwareEntityFinderDelegate(mediaFolder, delegate, Optional.of(path)));</span>
}
/*******************************************************************************************************************
*
* {@inheritDoc}
*
******************************************************************************************************************/
@Override @Nonnull
protected List<? extends PathAwareEntity> computeResults()
{
<span class="fc" id="L151"> return new CopyOnWriteArrayList<>(optionalPath.flatMap(path -> filteredByPath(path).map(e -> singletonList(e)))</span>
<span class="fc" id="L152"> .orElse((List)delegate.results()));</span>
}
/*******************************************************************************************************************
*
* {@inheritDoc}
*
******************************************************************************************************************/
@Override @Nonnegative
public int count()
{
<span class="nc" id="L163"> optionalPath.ifPresent(path -> log.warn("Path present: {} - count won't be a native query", path));</span>
<span class="nc" id="L164"> return optionalPath.map(path -> filteredByPath(path).map(entity -> 1).orElse(0))</span>
<span class="nc" id="L165"> .orElse(delegate.count());</span>
}
/*******************************************************************************************************************
*
*
*
******************************************************************************************************************/
@Nonnull
private Optional<? extends PathAwareEntity> filteredByPath (@Nonnull final Path path)
{
<span class="fc" id="L176"> log.debug("filteredByPath({})", path);</span>
<span class="fc bfc" id="L177" title="All 2 branches covered."> return mediaFolder.getPath().equals(path)</span>
<span class="fc" id="L178"> ? Optional.of(mediaFolder)</span>
<span class="fc bfc" id="L179" title="All 2 branches covered."> : childMatchingPathHead(path).flatMap(entity -> path.equals(entity.getPath())</span>
<span class="fc" id="L180"> ? Optional.of(entity)</span>
<span class="fc" id="L181"> : childMatchingPath(entity, path));</span>
}
/*******************************************************************************************************************
*
* Returns the child entity that matches the first element of the path, if present. The path can be exactly the one
* of the found entity, or it can be of one of its children.
*
* This method performs a bulk query of all children and then filters by path in memory. It is not possible to
* use a query to the native store for the path - which would be good for performance reasons - , because even
* though each segment of the path is function of some attribute of the related {@code PathAwareEntity} - typically
* the id - it is not a matter of the native store. Performance of this section relies upon memory caching. Some
* experiment showed that it's not useful to add another caching layer here, and the one in
* {@code RepositoryFinderSupport} is enough.
*
* @param path the path
* @return the entity, if present
*
******************************************************************************************************************/
@Nonnull
private Optional<PathAwareEntity> childMatchingPathHead (@Nonnull final Path path)
{
// assert filtered.size() == 1 or 0;
<span class="fc" id="L204"> log.debug(">>>> bulk query to {}, filtering in memory", delegate);</span>
<span class="fc" id="L205"> return (Optional<PathAwareEntity>)delegate.results().stream()</span>
<span class="fc" id="L206"> .filter(entity -> sameHead(relative(path), relative(entity.getPath())))</span>
<span class="fc" id="L207"> .findFirst();</span>
}
/*******************************************************************************************************************
*
* @param entity
* @param path the path
* @return the entity, if present
*
******************************************************************************************************************/
@Nonnull
private static Optional<PathAwareEntity> childMatchingPath (@Nonnull final PathAwareEntity entity,
@Nonnull final Path path)
{
<span class="fc" id="L221"> return ((PathAwareFinder)asSimpleComposite(entity).findChildren()).withPath(path).optionalResult();</span>
}
/*******************************************************************************************************************
*
*
*
******************************************************************************************************************/
@Nonnull // FIXME: this should be normally done by as()
this should be normally done by as()
private static SimpleComposite asSimpleComposite (@Nonnull final As object)
{
<span class="pc bpc" id="L232" title="1 of 2 branches missed."> return (object instanceof SimpleComposite) ? (SimpleComposite)object : object.as(_SimpleComposite_);</span>
}
/*******************************************************************************************************************
*
* Relativizes a path against the finder path, that is it removes the parent path. If the path can't be
* relativized, that is it doesn't start with the finder path, returns null.
*
******************************************************************************************************************/
@Nullable
private Path relative (@Nonnull final Path path)
{
<span class="fc bfc" id="L244" title="All 2 branches covered."> return mediaFolder.getParent().isEmpty() ? path :</span>
<span class="pc bpc" id="L245" title="1 of 2 branches missed."> path.startsWith(mediaFolder.getPath()) ? path.subpath(mediaFolder.getPath().getNameCount(), path.getNameCount())</span>
<span class="nc" id="L246"> : null;</span>
}
/*******************************************************************************************************************
*
*
*
******************************************************************************************************************/
private static boolean sameHead (@Nullable final Path path1, @Nullable final Path path2)
{
<span class="pc bpc" id="L256" title="2 of 6 branches missed."> return (path1 != null) && (path2 != null) && path1.getName(0).equals(path2.getName(0));</span>
}
}
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