Umbraco-CMS/src/Umbraco.Web.BackOffice/Trees/TreeController.cs

using System;
using System.Collections.Concurrent;
using Umbraco.Cms.Core;
using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Core.Trees;
using Umbraco.Extensions;

namespace Umbraco.Cms.Web.BackOffice.Trees
{
    /// <summary>
    /// The base controller for all tree requests
    /// </summary>
    public abstract class TreeController : TreeControllerBase
    {
        private static readonly ConcurrentDictionary<Type, TreeAttribute> _treeAttributeCache = new ConcurrentDictionary<Type, TreeAttribute>();

        private readonly TreeAttribute _treeAttribute;

        protected ILocalizedTextService LocalizedTextService { get; }

        protected TreeController(ILocalizedTextService localizedTextService, UmbracoApiControllerTypeCollection umbracoApiControllerTypeCollection, IEventAggregator eventAggregator)
            : base(umbracoApiControllerTypeCollection, eventAggregator)
        {
            LocalizedTextService = localizedTextService ?? throw new ArgumentNullException(nameof(localizedTextService));
            _treeAttribute = GetTreeAttribute();
        }

        /// <inheritdoc />
        public override string RootNodeDisplayName => Tree.GetRootNodeDisplayName(this, LocalizedTextService);

        /// <inheritdoc />
        public override string TreeGroup => _treeAttribute.TreeGroup;

        /// <inheritdoc />
        public override string TreeAlias => _treeAttribute.TreeAlias;

        /// <inheritdoc />
        public override string TreeTitle => _treeAttribute.TreeTitle;

        /// <inheritdoc />
        public override TreeUse TreeUse => _treeAttribute.TreeUse;

        /// <inheritdoc />
        public override string SectionAlias => _treeAttribute.SectionAlias;

        /// <inheritdoc />
        public override int SortOrder => _treeAttribute.SortOrder;

        /// <inheritdoc />
        public override bool IsSingleNodeTree => _treeAttribute.IsSingleNodeTree;

        private TreeAttribute GetTreeAttribute()
        {
            return _treeAttributeCache.GetOrAdd(GetType(), type =>
            {
                var treeAttribute = type.GetCustomAttribute<TreeAttribute>(false);
                if (treeAttribute == null)
                    throw new InvalidOperationException("The Tree controller is missing the " + typeof(TreeAttribute).FullName + " attribute");
                return treeAttribute;
            });
        }
    }
}