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JSimpleDB classes supporting Vaadin applications.
There is a newer version: 3.6.1

/*
 * Copyright (C) 2015 Archie L. Cobbs. All rights reserved.
 */

package org.jsimpledb.vaadin;

import com.google.common.base.Preconditions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Iterables;

import org.dellroad.stuff.vaadin7.PropertyDef;
import org.dellroad.stuff.vaadin7.PropertyExtractor;
import org.dellroad.stuff.vaadin7.ProvidesPropertyScanner;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Caches {@link org.dellroad.stuff.vaadin7.ProvidesProperty @ProvidesProperty}{@code(}{@link
 * JObjectContainer#REFERENCE_LABEL_PROPERTY}{@code )} methods for Java classes.
 */
final class ReferenceMethodInfoCache {

    static final PropertyInfo NOT_FOUND = new PropertyInfo<>(null, null);

    private static final ReferenceMethodInfoCache INSTANCE = new ReferenceMethodInfoCache();

    private final Logger log = LoggerFactory.getLogger(this.getClass());
    private final LoadingCache, PropertyInfo> cache = CacheBuilder.newBuilder().weakKeys().build(
      new CacheLoader, PropertyInfo>() {
        @Override
        public PropertyInfo load(Class type) {
            return ReferenceMethodInfoCache.this.findReferenceLablePropertyInfo(type);
        }
    });

    private ReferenceMethodInfoCache() {
    }

    /**
     * Get the singleton instance.
     */
    public static ReferenceMethodInfoCache getInstance() {
        return ReferenceMethodInfoCache.INSTANCE;
    }

    /**
     * Get property definition and extractor for the reference label method in the specified class, if any.
     *
     * @throws IllegalArgumentException if {@code type} is null
     */
    @SuppressWarnings("unchecked")
    public  PropertyInfo getReferenceMethodInfo(Class type) {
        return (PropertyInfo)this.cache.getUnchecked(type);
    }

    @SuppressWarnings("unchecked")
    private  PropertyInfo findReferenceLablePropertyInfo(Class type) {
        Preconditions.checkArgument(type != null, "null type");
        final ProvidesPropertyScanner scanner = new ProvidesPropertyScanner(type);
        final PropertyDef propertyDef = Iterables.find(scanner.getPropertyDefs(),
          pdef -> pdef.getName().equals(JObjectContainer.REFERENCE_LABEL_PROPERTY), null);
        return propertyDef != null ? new PropertyInfo(propertyDef, scanner.getPropertyExtractor()) : (PropertyInfo)NOT_FOUND;
    }

// PropertyInfo

    public static class PropertyInfo {

        private final PropertyDef propertyDef;
        private final PropertyExtractor propertyExtractor;

        PropertyInfo(PropertyDef propertyDef, PropertyExtractor propertyExtractor) {
            this.propertyDef = propertyDef;
            this.propertyExtractor = propertyExtractor;
        }

        public PropertyDef getPropertyDef() {
            return this.propertyDef;
        }

        public PropertyExtractor getPropertyExtractor() {
            return this.propertyExtractor;
        }
    }
}