com.expedia.seiso.web.hateoas.link.ItemLinks.java Source code

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Here is the source code for com.expedia.seiso.web.hateoas.link.ItemLinks.java

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/* 
 * Copyright 2013-2015 the original author or authors.
 * 
 * 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.
 */
package com.expedia.seiso.web.hateoas.link;

import java.net.URI;

import lombok.NonNull;
import lombok.RequiredArgsConstructor;
import lombok.val;

import org.springframework.data.domain.Page;
import org.springframework.stereotype.Component;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.util.UriComponentsBuilder;

import com.expedia.seiso.domain.entity.Dashboard;
import com.expedia.seiso.domain.entity.Item;
import com.expedia.seiso.domain.entity.ServiceInstance;
import com.expedia.seiso.domain.entity.SeyrenCheck;
import com.expedia.seiso.domain.meta.ItemMetaLookup;
import com.expedia.seiso.web.Relations;
import com.expedia.seiso.web.hateoas.Link;

/**
 * Various factory methods for creating item links. This does not include the repository search links, which
 * {@link RepoSearchLinks} handles.
 * 
 * @author Willie Wheeler
 */
@Component
@RequiredArgsConstructor
public class ItemLinks {
    private static final MultiValueMap<String, String> EMPTY_PARAMS = new LinkedMultiValueMap<>();

    /** Includes version prefix; e.g., /v1, /v2 */
    @NonNull
    private URI versionUri;

    @NonNull
    private ItemPaths itemPaths;
    @NonNull
    private ItemMetaLookup itemMetaLookup;

    // =================================================================================================================
    // Repo links
    // =================================================================================================================

    public Link repoLink(@NonNull Class<?> itemClass, @NonNull MultiValueMap<String, String> params) {
        return doRepoLink(Relations.SELF, itemClass, params);
    }

    public Link repoLink(@NonNull String rel, @NonNull Class<?> itemClass) {
        return doRepoLink(rel, itemClass, EMPTY_PARAMS);
    }

    public Link repoFirstLink(@NonNull Class<?> itemClass, @NonNull Page<?> page,
            @NonNull MultiValueMap<String, String> params) {

        val newParams = new LinkedMultiValueMap<String, String>(params);
        newParams.set("page", "0");
        return doRepoLink(Relations.FIRST, itemClass, newParams);
    }

    public Link repoPrevLink(@NonNull Class<?> itemClass, @NonNull Page<?> page,
            @NonNull MultiValueMap<String, String> params) {

        val newParams = new LinkedMultiValueMap<String, String>(params);
        newParams.set("page", String.valueOf(page.getNumber() - 1));
        return doRepoLink(Relations.PREVIOUS, itemClass, newParams);
    }

    public Link repoNextLink(@NonNull Class<?> itemClass, @NonNull Page<?> page,
            @NonNull MultiValueMap<String, String> params) {

        val newParams = new LinkedMultiValueMap<String, String>(params);
        newParams.set("page", String.valueOf(page.getNumber() + 1));
        return doRepoLink(Relations.NEXT, itemClass, newParams);
    }

    public Link repoLastLink(@NonNull Class<?> itemClass, @NonNull Page<?> page,
            @NonNull MultiValueMap<String, String> params) {

        val newParams = new LinkedMultiValueMap<String, String>(params);
        newParams.set("page", String.valueOf(page.getTotalPages() - 1));
        return doRepoLink(Relations.LAST, itemClass, newParams);
    }

    // =================================================================================================================
    // Item links
    // =================================================================================================================

    /**
     * Returns a self link to the given item.
     * 
     * @param item
     *            item
     * @return self link to the item.
     */
    public Link itemLink(@NonNull Item item) {
        return itemLink(Relations.SELF, item);
    }

    public Link itemLink(@NonNull String rel, @NonNull Item item) {
        return itemLink(rel, item, EMPTY_PARAMS);
    }

    public Link itemLink(@NonNull String rel, @NonNull Item item, @NonNull MultiValueMap<String, String> params) {
        // @formatter:off
        val href = repoUri(item.getClass(), params).pathSegment(itemPathSegment(item)).build().toString();
        // @formatter:on
        return new Link(rel, href);
    }

    public Link itemPropertyLink(@NonNull Item item, @NonNull String prop) {
        // @formatter:off
        val href = repoUri(item.getClass(), EMPTY_PARAMS).pathSegment(itemPathSegment(item)).pathSegment(prop)
                .build().toString();
        // @formatter:on
        return new Link("s:" + prop, href);
    }

    // =================================================================================================================
    // Special item links
    // =================================================================================================================

    public Link serviceInstanceNodeStatsLink(String rel, @NonNull ServiceInstance serviceInstance) {
        val href = repoUri(ServiceInstance.class, EMPTY_PARAMS).pathSegment(itemPathSegment(serviceInstance))
                .pathSegment("node-stats").build().toString();
        return new Link(rel, href);
    }

    public Link dashboardApiLink(@NonNull Dashboard dashboard) {
        val href = dashboard.getApiUri();
        return (href == null ? null : new Link(Relations.S_DASHBOARD_API, href));
    }

    public Link dashboardUiLink(@NonNull Dashboard dashboard) {
        val href = dashboard.getUiUri();
        return (href == null ? null : new Link(Relations.S_DASHBOARD_API, href));
    }

    public Link seyrenCheckApiLink(@NonNull SeyrenCheck check) {
        val source = check.getSource();
        assert (source != null);
        val href = source.getBaseUri() + "/api/checks/" + check.getSeyrenId();
        return new Link(Relations.S_SEYREN_CHECK_API, href);
    }

    public Link seyrenCheckUiLink(@NonNull SeyrenCheck check) {
        val source = check.getSource();
        assert (source != null);
        val href = source.getBaseUri() + "/#/checks/" + check.getSeyrenId();
        return new Link(Relations.S_SEYREN_CHECK_UI, href);
    }

    // =================================================================================================================
    // Private
    // =================================================================================================================

    private Link doRepoLink(String rel, Class<?> itemClass, MultiValueMap<String, String> params) {
        // @formatter:off
        val href = repoUri(itemClass, params).pathSegment(repoPath(itemClass)).build().toString();
        // @formatter:on
        return new Link(rel, href);
    }

    private UriComponentsBuilder repoUri(Class<?> itemClass, MultiValueMap<String, String> params) {
        // @formatter:off
        return UriComponentsBuilder.fromUri(versionUri).queryParams(params);
        // @formatter:on
    }

    private String repoPath(Class<?> itemClass) {
        return itemMetaLookup.getItemMeta(itemClass).getRepoKey();
    }

    private String[] itemPathSegment(Item item) {
        return itemPaths.convert(item);
    }
}