persistent_classes.po

hibernate-distribution-3.3.1.GA-dist.zip源码

#. Tag: para
#: persistent_classes.xml:107
#, no-c-format
msgid ""
"You should also avoid declaring <literal>public final</literal> methods on "
"the non-final classes. If you want to use a class with a <literal>public "
"final</literal> method, you must explicitly disable proxying by setting "
"<literal>lazy=\"false\"</literal>."
msgstr ""
"You should also avoid declaring <literal>public final</literal> methods on "
"the non-final classes. If you want to use a class with a <literal>public "
"final</literal> method, you must explicitly disable proying by setting "
"<literal>lazy=\"false\"</literal>."

#. Tag: title
#: persistent_classes.xml:115
#, no-c-format
msgid "Declare accessors and mutators for persistent fields (optional)"
msgstr "Declare accessors and mutators for persistent fields (optional)"

#. Tag: para
#: persistent_classes.xml:117
#, no-c-format
msgid ""
"<literal>Cat</literal> declares accessor methods for all its persistent "
"fields. Many other ORM tools directly persist instance variables. We believe "
"it is better to provide an indirection between the relational schema and "
"internal data structures of the class. By default, Hibernate persists "
"JavaBeans style properties, and recognizes method names of the form "
"<literal>getFoo</literal>, <literal>isFoo</literal> and <literal>setFoo</"
"literal>. You may switch to direct field access for particular properties, "
"if needed."
msgstr ""
"<literal>Cat</literal> declares accessor methods for all its persistent "
"fields. Many other ORM tools directly persist instance variables. We believe "
"it is better to provide an indirection between the relational schema and "
"internal data structures of the class. By default, Hibernate persists "
"JavaBeans style properties, and recognizes method names of the form "
"<literal>getFoo</literal>, <literal>isFoo</literal> and <literal>setFoo</"
"literal>. You may switch to direct field access for particular properties, "
"if needed."

#. Tag: para
#: persistent_classes.xml:127
#, no-c-format
msgid ""
"Properties need <emphasis>not</emphasis> be declared public - Hibernate can "
"persist a property with a default, <literal>protected</literal> or "
"<literal>private</literal> get / set pair."
msgstr ""
"Properties need <emphasis>not</emphasis> be declared public - Hibernate can "
"persist a property with a default, <literal>protected</literal> or "
"<literal>private</literal> get / set pair."

#. Tag: title
#: persistent_classes.xml:138
#, no-c-format
msgid "Implementing inheritance"
msgstr "Implementing inheritance"

#. Tag: para
#: persistent_classes.xml:140
#, no-c-format
msgid ""
"A subclass must also observe the first and second rules. It inherits its "
"identifier property from the superclass, <literal>Cat</literal>."
msgstr ""
"A subclass must also observe the first and second rules. It inherits its "
"identifier property from the superclass, <literal>Cat</literal>."

#. Tag: programlisting
#: persistent_classes.xml:145
#, no-c-format
msgid ""
"<![CDATA[package eg;\n"
"\n"
"public class DomesticCat extends Cat {\n"
"        private String name;\n"
"\n"
"        public String getName() {\n"
"                return name;\n"
"        }\n"
"        protected void setName(String name) {\n"
"                this.name=name;\n"
"        }\n"
"}]]>"
msgstr ""

#. Tag: title
#: persistent_classes.xml:149
#, no-c-format
msgid ""
"Implementing <literal>equals()</literal> and <literal>hashCode()</literal>"
msgstr ""
"Implementing <literal>equals()</literal> and <literal>hashCode()</literal>"

#. Tag: para
#: persistent_classes.xml:151
#, no-c-format
msgid ""
"You have to override the <literal>equals()</literal> and <literal>hashCode()"
"</literal> methods if you"
msgstr ""
"You have to override the <literal>equals()</literal> and <literal>hashCode()"
"</literal> methods if you"

#. Tag: para
#: persistent_classes.xml:157
#, no-c-format
msgid ""
"intend to put instances of persistent classes in a <literal>Set</literal> "
"(the recommended way to represent many-valued associations) <emphasis>and</"
"emphasis>"
msgstr ""
"intend to put instances of persistent classes in a <literal>Set</literal> "
"(the recommended way to represent many-valued associations) <emphasis>and</"
"emphasis>"

#. Tag: para
#: persistent_classes.xml:164
#, no-c-format
msgid "intend to use reattachment of detached instances"
msgstr "intend to use reattachment of detached instances"

#. Tag: para
#: persistent_classes.xml:170
#, no-c-format
msgid ""
"Hibernate guarantees equivalence of persistent identity (database row) and "
"Java identity only inside a particular session scope. So as soon as we mix "
"instances retrieved in different sessions, we must implement <literal>equals"
"()</literal> and <literal>hashCode()</literal> if we wish to have meaningful "
"semantics for <literal>Set</literal>s."
msgstr ""
"Hibernate guarantees equivalence of persistent identity (database row) and "
"Java identity only inside a particular session scope. So as soon as we mix "
"instances retrieved in different sessions, we must implement <literal>equals"
"()</literal> and <literal>hashCode()</literal> if we wish to have meaningful "
"semantics for <literal>Set</literal>s."

#. Tag: para
#: persistent_classes.xml:178
#, no-c-format
msgid ""
"The most obvious way is to implement <literal>equals()</literal>/"
"<literal>hashCode()</literal> by comparing the identifier value of both "
"objects. If the value is the same, both must be the same database row, they "
"are therefore equal (if both are added to a <literal>Set</literal>, we will "
"only have one element in the <literal>Set</literal>). Unfortunately, we "
"can't use that approach with generated identifiers! Hibernate will only "
"assign identifier values to objects that are persistent, a newly created "
"instance will not have any identifier value! Furthermore, if an instance is "
"unsaved and currently in a <literal>Set</literal>, saving it will assign an "
"identifier value to the object. If <literal>equals()</literal> and "
"<literal>hashCode()</literal> are based on the identifier value, the hash "
"code would change, breaking the contract of the <literal>Set</literal>. See "
"the Hibernate website for a full discussion of this problem. Note that this "
"is not a Hibernate issue, but normal Java semantics of object identity and "
"equality."
msgstr ""
"The most obvious way is to implement <literal>equals()</literal>/"
"<literal>hashCode()</literal> by comparing the identifier value of both "
"objects. If the value is the same, both must be the same database row, they "
"are therefore equal (if both are added to a <literal>Set</literal>, we will "
"only have one element in the <literal>Set</literal>). Unfortunately, we "
"can't use that approach with generated identifiers! Hibernate will only "
"assign identifier values to objects that are persistent, a newly created "
"instance will not have any identifier value! Furthermore, if an instance is "
"unsaved and currently in a <literal>Set</literal>, saving it will assign an "
"identifier value to the object. If <literal>equals()</literal> and "
"<literal>hashCode()</literal> are based on the identifier value, the hash "
"code would change, breaking the contract of the <literal>Set</literal>. See "
"the Hibernate website for a full discussion of this problem. Note that this "
"is not a Hibernate issue, but normal Java semantics of object identity and "
"equality."

#. Tag: para
#: persistent_classes.xml:192
#, no-c-format
msgid ""
"We recommend implementing <literal>equals()</literal> and <literal>hashCode()"
"</literal> using <emphasis>Business key equality</emphasis>. Business key "
"equality means that the <literal>equals()</literal> method compares only the "
"properties that form the business key, a key that would identify our "
"instance in the real world (a <emphasis>natural</emphasis> candidate key):"
msgstr ""
"We recommend implementing <literal>equals()</literal> and <literal>hashCode()"
"</literal> using <emphasis>Business key equality</emphasis>. Business key "
"equality means that the <literal>equals()</literal> method compares only the "
"properties that form the business key, a key that would identify our "
"instance in the real world (a <emphasis>natural</emphasis> candidate key):"

#. Tag: programlisting
#: persistent_classes.xml:200
#, no-c-format
msgid ""
"<![CDATA[public class Cat {\n"
"\n"
"    ...\n"
"    public boolean equals(Object other) {\n"
"        if (this == other) return true;\n"
"        if ( !(other instanceof Cat) ) return false;\n"
"\n"
"        final Cat cat = (Cat) other;\n"
"\n"
"        if ( !cat.getLitterId().equals( getLitterId() ) ) return false;\n"
"        if ( !cat.getMother().equals( getMother() ) ) return false;\n"
"\n"
"        return true;\n"
"    }\n"
"\n"
"    public int hashCode() {\n"
"        int result;\n"
"        result = getMother().hashCode();\n"
"        result = 29 * result + getLitterId();\n"
"        return result;\n"
"    }\n"
"\n"
"}]]>"
msgstr ""

#. Tag: para
#: persistent_classes.xml:202
#, no-c-format
msgid ""
"Note that a business key does not have to be as solid as a database primary "
"key candidate (see <xref linkend=\"transactions-basics-identity\"/>). "
"Immutable or unique properties are usually good candidates for a business "
"key."
msgstr ""
"Note that a business key does not have to be as solid as a database primary "
"key candidate (see <xref linkend=\"transactions-basics-identity\"/>). "
"Immutable or unique properties are usually good candidates for a business "
"key."

#. Tag: title
#: persistent_classes.xml:212
#, no-c-format
msgid "Dynamic models"
msgstr "Dynamic models"

#. Tag: emphasis
#: persistent_classes.xml:215
#, no-c-format
msgid ""
"Note that the following features are currently considered experimental and "
"may change in the near future."
msgstr ""
"Note that the following features are currently considered experimental and "
"may change in the near future."

#. Tag: para
#: persistent_classes.xml:219
#, no-c-format
msgid ""
"Persistent entities don't necessarily have to be represented as POJO classes "
"or as JavaBean objects at runtime. Hibernate also supports dynamic models "
"(using <literal>Map</literal>s of <literal>Map</literal>s at runtime) and "
"the representation of entities as DOM4J trees. With this approach, you don't "
"write persistent classes, only mapping files."
msgstr ""
"Persistent entities don't necessarily have to be represented as POJO classes "
"or as JavaBean objects at runtime. Hibernate also supports dynamic models "
"(using <literal>Map</literal>s of <literal>Map</literal>s at runtime) and "
"the representation of entities as DOM4J trees. With this approach, you don't "
"write persistent classes, only mapping files."

#. Tag: para
#: persistent_classes.xml:227
#, no-c-format
msgid ""
"By default, Hibernate works in normal POJO mode. You may set a default "
"entity representation mode for a particular <literal>SessionFactory</"
"literal> using the <literal>default_entity_mode</literal> configuration "
"option (see <xref linkend=\"configuration-optional-properties\"/>."
msgstr ""
"By default, Hibernate works in normal POJO mode. You may set a default "
"entity representation mode for a particular <literal>SessionFactory</"
"literal> using the <literal>default_entity_mode</literal> configuration "
"option (see <xref linkend=\"configuration-optional-properties\"/>."

#. Tag: para
#: persistent_classes.xml:234
#, no-c-format
msgid ""
"The following examples demonstrates the representation using <literal>Map</"
"literal>s. First, in the mapping file, an <literal>entity-name</literal> has "