nucleus/businessobjects/src/main/java/org/eclipse/mdm/businessobjects/boundary/LocalizationResource.java

/********************************************************************************
 * Copyright (c) 2015-2021 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 ********************************************************************************/

package org.eclipse.mdm.businessobjects.boundary;

import static org.eclipse.mdm.businessobjects.boundary.ResourceConstants.REQUESTPARAM_SOURCENAME;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;

import javax.ejb.EJB;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.eclipse.mdm.api.base.model.MDMLocalization;
import org.eclipse.mdm.businessobjects.entity.MDMEntityResponse;
import org.eclipse.mdm.businessobjects.utils.ServiceUtils;

import io.swagger.v3.oas.annotations.Operation;
import io.swagger.v3.oas.annotations.Parameter;
import io.swagger.v3.oas.annotations.media.Content;
import io.swagger.v3.oas.annotations.media.Schema;
import io.swagger.v3.oas.annotations.responses.ApiResponse;
import io.swagger.v3.oas.annotations.tags.Tag;

/**
 * 
 * @author jst
 *
 */

@Tag(name = "Localization")
@Path("/environments/{" + REQUESTPARAM_SOURCENAME + "}/mdmlocalizations")
public class LocalizationResource {

	private static final String LOCALIZATION_PREFIX = "mdm://i18n/";

	@EJB
	private LocalizationService localizationService;

	@GET
	@Operation(summary = "Get all localizations", description = "Returns all localizations as hierarchical map", responses = {
			@ApiResponse(description = "All localizations as map", content = @Content(schema = @Schema(implementation = Map.class))),
			@ApiResponse(responseCode = "400", description = "Error") })
	@Produces(MediaType.APPLICATION_JSON + "+packed")
	public Response read(
			@Parameter(description = "Name of the MDM datasource", required = true) @PathParam(REQUESTPARAM_SOURCENAME) String sourceName) {
		return ServiceUtils.toResponse(groupByKey(localizationService.localize(sourceName)));
	}

	@GET
	@Operation(summary = "Get all localizations as entities", description = "Returns all localizations as list of MDMLocalization entities.", responses = {
			@ApiResponse(description = "All localizations", content = @Content(schema = @Schema(implementation = MDMEntityResponse.class))),
			@ApiResponse(responseCode = "400", description = "Error") })
	@Produces(MediaType.APPLICATION_JSON)
	public Response readEntities(
			@Parameter(description = "Name of the MDM datasource", required = true) @PathParam(REQUESTPARAM_SOURCENAME) String sourceName) {
		return ServiceUtils
				.toResponse(new MDMEntityResponse(MDMLocalization.class, localizationService.localize(sourceName)));

	}

	@GET
	@Operation(summary = "Get default mimetypes", description = "Returns all default mimetypes.", responses = {
			@ApiResponse(description = "All default mimetypes", content = @Content(schema = @Schema(implementation = Map.class))),
			@ApiResponse(responseCode = "400", description = "Error") })
	@Produces(MediaType.APPLICATION_JSON)
	@Path("mimetypes")
	public Response getDefaultMimeTypes(
			@Parameter(description = "Name of the MDM datasource", required = true) @PathParam(REQUESTPARAM_SOURCENAME) String sourceName) {
		return ServiceUtils.toResponse(localizationService.getDefaultMimeTypes(sourceName));

	}

	/**
	 * Pack localization information, by organizing translations in a hierarchical
	 * map.
	 *
	 * Names of {@link MDMLocalization} are used as keys. The keys are split on
	 * slashes (not the escaped ones) and the prefix is omitted. The actual
	 * translation values are held as array of the AliasNames.
	 *
	 * @param localizations the flat list of {@link MDMLocalization} entities.
	 * @return hierarchical translation map
	 */
	private Map<String, Object> groupByKey(List<MDMLocalization> localizations) {
		Map<String, Object> result = new HashMap<>();
		for (MDMLocalization localization : localizations) {
			// remove prefix since it contains no information
			String key = localization.getName();
			if (key.contains(LOCALIZATION_PREFIX)) {
				key = key.substring(LOCALIZATION_PREFIX.length());
			}
			// create stack with key fragments in backward order
			String[] keyFragments = key.split("/");
			Stack<String> stack = new Stack<>();
			for (int i = keyFragments.length - 1; i >= 0; --i) {
				stack.push(keyFragments[i]);
			}
			// add to result map
			addToMap(result, stack, localization.getTranslations());
		}
		return result;
	}

	/**
	 * Adds translations recursively to a hierarchical map.
	 * 
	 * @param current      current submap
	 * @param keyStack     remaining key fragements
	 * @param translations array with translations
	 * @return
	 */
	@SuppressWarnings("unchecked")
	private void addToMap(Map<String, Object> current, Stack<String> keyStack, List<String> translations) {
		String key = keyStack.pop().replace("%2F", "/");
		// key chain contains more fragments
		if (!keyStack.isEmpty()) {
			// find existing sub-map or create and add new
			Map<String, Object> next;
			if (current.containsKey(key)) {
				next = (Map<String, Object>) current.get(key);
			} else {
				next = new HashMap<String, Object>();
				current.put(key, next);
			}
			// process next fragment in sub-map
			addToMap(next, keyStack, translations);
			// last key fragment reached, thus translations are inserted now.
		} else {
			// last wins
			current.put(key, translations);
		}
	}
}