com.erudika.para.core.Linkable Maven / Gradle / Ivy
/*
* Copyright 2013-2017 Erudika. https://erudika.com
*
* 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.
*
* For issues and patches go to: https://github.com/erudika
*/
package com.erudika.para.core;
import com.erudika.para.utils.Pager;
import java.util.List;
/**
* Applied to all {@link ParaObject}s by default. Allows an object to be linked to another object.
* A link can be: 1-1, 1-* or *-*. One-to-one and one-to-many links are implemented using the {@code parentid} field.
* Many-to-many links are implemented using {@link Linker} objects.
* @author Alex Bogdanovski [[email protected]]
* @see Linker
*/
public interface Linkable {
/**
* Count the total number of links between this object and another type of object.
* @param type2 the other type of object
* @return the number of links
*/
Long countLinks(String type2);
/**
* Returns all links between this type object and another type of object.
* @param type2 the other type of object
* @param pager a {@link com.erudika.para.utils.Pager}
* @return a list of {@code Linker} objects in a many-to-many relationship with this object.
*/
List getLinks(String type2, Pager... pager);
/**
* Similar to {@link #getChildren(java.lang.String, com.erudika.para.utils.Pager...) }
* but for many-to-many relationships.
* @param type of linked objects
* @param type type of linked objects to look for
* @param pager a {@link com.erudika.para.utils.Pager}
* @return a list of linked objects
*/
List
getLinkedObjects(String type, Pager... pager);
/**
* Similar to {@link #findChildren(java.lang.String, java.lang.String, com.erudika.para.utils.Pager...)}
* but for many-to-many relationships. Searches through all linked objects connected to this via
* a {@link Linker} object.
* @param
type of linked objects
* @param type type of linked objects to look for
* @param pager a {@link com.erudika.para.utils.Pager}
* @param field the name of the field to target (within a nested field "nstd")
* @param query a query string
* @return a list of linked objects matching the search query
*/
List
findLinkedObjects(String type, String field, String query, Pager... pager);
/**
* Checks if this object is linked to another.
* @param type2 the other type
* @param id2 the other id
* @return true if the two are linked
*/
boolean isLinked(String type2, String id2);
/**
* Checks if a given object is linked to this one.
* @param toObj the other object
* @return true if linked
*/
boolean isLinked(ParaObject toObj);
/**
* Links an object to this one in a many-to-many relationship.
* Only a link is created. Objects are left untouched.
* The type of the second object is automatically determined on read.
* @param id2 the other id
* @return the id of the {@link Linker} object that is created
*/
String link(String id2);
/**
* Unlinks an object from this one.
* Only a link is deleted. Objects are left untouched.
* @param type the other type
* @param id2 the other id
*/
void unlink(String type, String id2);
/**
* Unlinks all objects that are linked to this one.
* Deletes all {@link Linker} objects. Only the links are deleted. Objects are left untouched.
*/
void unlinkAll();
/**
* Count the total number of child objects for this object.
* @param type the other type of object
* @return the number of links
*/
Long countChildren(String type);
/**
* Returns all child objects linked to this object.
* @param
the type of children
* @param type the type of children to look for
* @param pager a {@link com.erudika.para.utils.Pager}
* @return a list of {@link ParaObject} in a one-to-many relationship with this object
*/
List
getChildren(String type, Pager... pager);
/**
* Search through all child objects. Only searches child objects directly
* connected to this parent via the {@code parentid} field.
* @param
the type of children
* @param type the type of children to look for
* @param pager a {@link com.erudika.para.utils.Pager}
* @param query a query string
* @return a list of {@link ParaObject} in a one-to-many relationship with this object
*/
List
findChildren(String type, String query, Pager... pager);
/**
* Returns all child objects linked to this object.
* @param
the type of children
* @param type the type of children to look for
* @param field the field name to use as filter
* @param term the field value to use as filter
* @param pager a {@link com.erudika.para.utils.Pager}
* @return a list of {@link ParaObject} in a one-to-many relationship with this object
*/
List
getChildren(String type, String field, String term, Pager... pager);
/**
* Deletes all child objects permanently.
* @param type the children's type.
*/
void deleteChildren(String type);
}