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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);
    
    /*
    /**********************************************************
    /* 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 */ private final Class type; /** * Scope of the Object Id (may be null, to denote global) */ private final Class scope; /** * Object for which Object Id was generated: can NOT be null. */ private final Object key; /** * Hash code */ private final int hashCode; public IdKey(Class type, Class scope, Object 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); } } }





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