sirius.db.mixing.Mapping Maven / Gradle / Ivy
Show all versions of sirius-db Show documentation
/*
* Made with all the love in the world
* by scireum in Remshalden, Germany
*
* Copyright by scireum GmbH
* http://www.scireum.de - [email protected]
*/
package sirius.db.mixing;
import sirius.kernel.commons.Strings;
import javax.annotation.Nullable;
import java.util.Objects;
/**
* Represents a column (property) name which is used in queries.
*
* For each field, a Mapping with the same name must be defined. This mapping is used to reference the
* field (or its property) in queries. This adds syntactic checks and permits refactorings (renaming etc.).
*
* An example for a field with its mapping would be:
*
* {@code
* public static final Mapping AGE = Mapping.named("age");
* private int age;
* }
*
*/
public class Mapping {
/**
* Used to join several field names (e.g. for composites or mixins).
*/
public static final String SUBFIELD_SEPARATOR = "_";
/**
* Used to join several field names (e.g. for nesteds).
*/
public static final String NESTED_SEPARATOR = ".";
/**
* Contains the name of the represented field
*/
private final String name;
/**
* Contains the parent in case this field resides in a composite or mixin
*/
private final Mapping parent;
/*
* Creates a new mapping. Use named(String) to create a new constant within a class. Use inner(Mapping) or
* join(Mapping) to access composites, mixins or referenced entities.
*/
private Mapping(String name, Mapping parent) {
this.name = name;
this.parent = parent;
}
/**
* Creates a new Mapping. This should be used to create a public static final constant
* in the class where the field is defined.
*
* @param name the name of the represented field
* @return a mapping representing the field with the given name
*/
public static Mapping named(String name) {
return new Mapping(name, null);
}
/**
* Creates a new Mapping for a mixin class.
*
* @param mixinType the class which defines the mixin
* @return a mapping representing the mixin
*/
public static Mapping mixin(Class mixinType) {
return new Mapping(mixinType.getSimpleName(), null);
}
/**
* References an inner field of a composite represented by this mapping.
*
* @param inner the inner field of the composite represented by this mapping
* @return a mapping representing the combined path of this mapping and inner field
*/
public Mapping inner(Mapping inner) {
return new Mapping(name + SUBFIELD_SEPARATOR + inner.name, null);
}
/**
* References a field of a nested list or map represented by this mapping.
*
* This is the equivalent of {@link #join(Mapping)} for NOSQL databases like Elasticsearch or Mongo DB.
*
* @param inner the inner field of the nested represented by this mapping
* @return a mapping representing the combined path of this mapping and inner field
*/
public Mapping nested(Mapping inner) {
return new Mapping(name + NESTED_SEPARATOR + inner.name, null);
}
/**
* References a dynamic inner property of a nested map represented by this mapping.
*
* This is the equivalent of {@link #join(Mapping)} for NOSQL databases like Elasticsearch or Mongo DB.
*
* @param inner the inner field of the nested represented by this mapping
* @return a mapping representing the combined path of this mapping and inner field
*/
public Mapping nested(String inner) {
return new Mapping(name + NESTED_SEPARATOR + inner, null);
}
/**
* References a mixin for an inner composite or referenced type.
*
* @param mixinType t the class which defines the mixin
* @return a mapping representing the combined path of this mapping and the given mixin
*/
public Mapping inMixin(Class mixinType) {
return new Mapping(mixinType.getSimpleName() + SUBFIELD_SEPARATOR + name, null);
}
/**
* Joins the referenced field described by joinMapping.
*
* Note that this mapping needs to represent an EntityRef field.
*
* @param joinMapping the mapping of the referenced entity to join
* @return a mapping which joins the entity represented by this mapping and accesses the given joinMapping
*/
public Mapping join(Mapping joinMapping) {
return new Mapping(joinMapping.name, this);
}
/**
* Returns the field name for which this mapping was created.
*
* Note that this is not necessarily the property name as for properties in mixins or compounds, the
* parent fields are appended separated by {@link #SUBFIELD_SEPARATOR}.
*
* @return the field name for which this mapping was created
*/
public String getName() {
return name;
}
/**
* Returns the parent field.
*
* @return the parent field (the composite or mixin which contains this mapping). Returns null if this is
* a top-level field of an entity
*/
@Nullable
public Mapping getParent() {
return parent;
}
@Override
public String toString() {
if (parent != null) {
return parent.toString() + "." + name;
} else {
return name;
}
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj == null) {
return false;
}
if (obj.getClass() != Mapping.class) {
return false;
}
Mapping other = (Mapping) obj;
return Strings.areEqual(name, other.getName()) && Objects.equals(parent, other.getParent());
}
@Override
public int hashCode() {
if (parent == null) {
return name.hashCode();
}
return name.hashCode() + 17 * parent.hashCode();
}
}