org.eclipse.opencert.elastic/src/org/eclipse/opencert/elastic/search/HitResolution.java

/*******************************************************************************
 * Copyright (C) 2018 ANSYS medini Technologies AG
 * 
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 * 
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors: 
 * 	ANSYS medini Technologies AG - initial API and implementation
 ******************************************************************************/
package org.eclipse.opencert.elastic.search;

import java.util.HashSet;
import java.util.Set;

/**
 * Abstraction layer to resolve any "Hit" back to an object using an
 * {@link ObjectResolver} within a given context.
 *
 * @author mauersberger
 */
public class HitResolution<T> {

	// the context we are working on, e.g. a list of objects or a tree or a database
	private Object context;

	// the resolver to do the real job
	private ObjectResolver<? extends T> objectResolver;

	/**
	 * Factory to create a new {@link HitResolution} object working on the given
	 * context
	 *
	 * @param context
	 *            an arbitrary context that can be interpreted by the
	 *            {@link ObjectResolver}
	 * @return the new {@link HitResolution}
	 */
	public static <T> HitResolution<T> on(Object context) {
		HitResolution<T> resolution = new HitResolution<>();
		// XXX hack
		resolution.context = DummyData.INSTANCE.convert(context);
		return resolution;
	}

	/**
	 * Use the given {@link ObjectResolver} when resolving a hit.
	 *
	 * @param resolver
	 *            the resolver (should match the context)
	 * @return this
	 */
	public HitResolution<T> using(ObjectResolver<? extends T> resolver) {
		objectResolver = resolver;
		return this;
	}

	public T resolve(Hit hit) {
		if (objectResolver == null) {
			throw new IllegalStateException("an object resolver is missing - use with(...) before"); //$NON-NLS-1$
		}
		return objectResolver.resolve(hit.objectId, context);
	}

	public Set<T> resolve(Set<Hit> hits, int minScore) {
		Set<T> resolvedAll = new HashSet<>();
		for (Hit hit : hits) {
			if (hit.score < minScore) {
				// filter hits with low score
				continue;
			}

			T resolved = this.resolve(hit);
			if (resolved != null) {
				resolvedAll.add(resolved);
			}
		}

		return resolvedAll;
	}
}