JsonPath.java

package io.katharsis.request.path;

import java.util.Objects;

/**
 * Represent a JSON API path sent to the server. Each resource or field defined in the path is represented by one
 * derived class of JsonPath object.
 *
 * It is represented in a form of a doubly-linked list which must start with one or more ResourcePath instances and can
 * end with either FieldPath or LinksPath instance.
 */
public abstract class JsonPath {

    /**
     * Name of a resource or a filed
     */
    final String elementName;

    /**
     * Unique identifier of a field
     */
    PathIds ids;

    /**
     * Entry closer to path's beginning
     */
    JsonPath parentResource;

    /**
     * Entry closer to path's end
     */
    private JsonPath childResource;

    public JsonPath(String elementName) {
        this(elementName, null);
    }

    public JsonPath(String elementName, PathIds pathIds) {
        this.elementName = elementName;
        this.ids = pathIds;
    }

    /**
     * Returns true if a JsonPath concerns a collection.
     * It can happen if there's no or more than one id provided.
     *
     * @return true if a path concern a collection
     */
    public abstract boolean isCollection();

    /**
     * Returns name of a resource the last resource in requested path.
     * There can be paths that concern relations. In this case a elementName from parent JsonPath should be retrieved.
     *
     * @return nam of the lase resource
     */
    public abstract String getResourceName();

    /**
     * Returns name of the current element. It can be either resource type or resource's field.
     *
     * @return name of the element
     */
    public String getElementName() {
        return elementName;
    }

    public PathIds getIds() {
        return ids;
    }

    public void setIds(PathIds ids) {
        this.ids = ids;
    }

    public JsonPath getParentResource() {
        return parentResource;
    }

    public void setParentResource(JsonPath parentResource) {
        this.parentResource = parentResource;
    }

    public JsonPath getChildResource() {
        return childResource;
    }

    public void setChildResource(JsonPath childResource) {
        this.childResource = childResource;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        JsonPath jsonPath = (JsonPath) o;
        return Objects.equals(elementName, jsonPath.elementName) &&
                Objects.equals(ids, jsonPath.ids) &&
                Objects.equals(parentResource, jsonPath.parentResource);
    }

    @Override
    public int hashCode() {
        return Objects.hash(elementName, ids, parentResource);
    }
}