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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}).
     * 
     * @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 */ 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 */ 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'. */ 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. */ public abstract ObjectIdGenerator newForSerialization(Object context); /** * Method for constructing key to use for ObjectId-to-POJO maps. */ 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 final static 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 String.format("[ObjectId: key=%s, type=%s, scope=%s]", key, (type == null) ? "NONE" : type.getName(), (scope == null) ? "NONE" : scope.getName()); } } }





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