com.fasterxml.jackson.annotation.ObjectIdGenerator Maven / Gradle / Ivy
/*
* Copyright © 2019 Dominokit
*
* 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.fasterxml.jackson.annotation;
/**
* Definition of API used for constructing Object Identifiers (as annotated using {@link
* JsonIdentityInfo}). Also defines factory methods used for creating instances for serialization,
* deserialization.
*
* @param Type of Object Identifiers produced.
*/
@SuppressWarnings("serial")
public abstract class ObjectIdGenerator implements java.io.Serializable {
/*
/**********************************************************
/* Accessors
/**********************************************************
*/
public abstract Class getScope();
/**
* Method called to check whether this generator instance can be used for Object Ids of specific
* generator type and scope; determination is based by passing a configured "blueprint"
* (prototype) instance; from which the actual instances are created (using {@link
* #newForSerialization}).
*
* @param gen {@link ObjectIdGenerator}
* @return True if this instance can be used as-is; false if not
*/
public abstract boolean canUseFor(ObjectIdGenerator gen);
/**
* Accessor that needs to be overridden to return true if the Object Id may be
* serialized as JSON Object; used by, for example, JSOG handling. The reason accessor is needed
* is because handling such Object Ids is more complex and may incur additional buffering or
* performance overhead, avoiding of which makes sense for common case of scalar object ids (or
* native object ids some formats support).
*
* Default implementation returns false, so needs to be overridden by
* Object-producing generators.
*
* @since 2.5
* @return boolean
*/
public boolean maySerializeAsObject() {
return false;
}
/**
* Accessor that may be called (after verifying (via {@link #maySerializeAsObject()}) whether
* given name
*
* @param name Name of property to check
* @param parser Parser that points to property name, in case generator needs further verification
* (note: untyped, because JsonParser is defined in `jackson-core`, and this
* package does not depend on it).
* @since 2.5
* @return boolean
*/
public boolean isValidReferencePropertyName(String name, Object parser) {
return false;
}
/*
/**********************************************************
/* Factory methods
/**********************************************************
*/
/**
* Factory method to create a blueprint instance for specified scope. Generators that do not use
* scope may return 'this'.
*
* @param scope {@link Class}
* @return {@link ObjectIdGenerator}
*/
public abstract ObjectIdGenerator forScope(Class scope);
/**
* Factory method called to create a new instance to use for serialization: needed since
* generators may have state (next id to produce).
*
* Note that actual type of 'context' is
* com.fasterxml.jackson.databind.SerializerProvider, but can not be declared here as type
* itself (as well as call to this object) comes from databind package.
*
* @param context Serialization context object used (of type
* com.fasterxml.jackson.databind.SerializerProvider; may be needed by more complex
* generators to access contextual information such as configuration.
* @return {@link ObjectIdGenerator}
*/
public abstract ObjectIdGenerator newForSerialization(Object context);
/**
* Method for constructing key to use for ObjectId-to-POJO maps.
*
* @param key {@link Object}
* @return {@link IdKey}
*/
public abstract IdKey key(Object key);
/*
/**********************************************************
/* Methods for serialization
/**********************************************************
*/
/**
* Method used for generating a new Object Identifier to serialize for given POJO.
*
* @param forPojo POJO for which identifier is needed
* @return Object Identifier to use.
*/
public abstract T generateId(Object forPojo);
/*
/**********************************************************
/* Helper classes
/**********************************************************
*/
/**
* Simple key class that can be used as a key for ObjectId-to-POJO mappings, when multiple
* ObjectId types and scopes are used.
*/
public static final class IdKey implements java.io.Serializable {
private static final long serialVersionUID = 1L;
/** Type of {@link ObjectIdGenerator} used for generating Object Id */
public final Class type;
/** Scope of the Object Id (may be null, to denote global) */
public final Class scope;
/** Object for which Object Id was generated: can NOT be null. */
public final Object key;
private final int hashCode;
public IdKey(Class type, Class scope, Object key) {
if (key == null) {
throw new IllegalArgumentException("Can not construct IdKey for null key");
}
this.type = type;
this.scope = scope;
this.key = key;
int h = key.hashCode() + type.getName().hashCode();
if (scope != null) {
h ^= scope.getName().hashCode();
}
hashCode = h;
}
@Override
public int hashCode() {
return hashCode;
}
@Override
public boolean equals(Object o) {
if (o == this) return true;
if (o == null) return false;
if (o.getClass() != getClass()) return false;
IdKey other = (IdKey) o;
return (other.key.equals(key)) && (other.type == type) && (other.scope == scope);
}
@Override
public String toString() {
return "[ObjectId: key="
+ key
+ ", type="
+ ((type == null) ? "NONE" : type.getName())
+ ", scope="
+ ((scope == null) ? "NONE" : scope.getName())
+ "]";
}
}
}