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POI can't access a list after query in a one-to-many relation with Hibernate and Criteria
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  1. POI can't access a list after query in a one-to-many relation with Hibernate and Criteria
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    copied!<p>I have a problem with Hibernate, one-to-many associations and lists. In my model, I have countries and, for each country, I have multiple information describing a structure for addresses in that country. I want to access the list of these elements.</p> <p>This my class Country :</p> <pre><code>public class Country { private Long id; private String name; private List&lt;AddressElement&gt; addressElementList = null; ... } </code></pre> <p>My class AddressElement:</p> <pre><code>public class AddressElement { private Long id; private int pos; private int line; private String name; private String mask; ... } </code></pre> <p>And my mappings :</p> <pre><code>&lt;hibernate-mapping package="org.devtutos.tuto5.domaine"&gt; &lt;class name="Country" table="tuto.COUNTRY"&gt; &lt;id name="id" type="java.lang.Long" column="COUNTRY_ID" unsaved-value="null"&gt; &lt;generator class="native"&gt; &lt;param name="sequence"&gt;tuto.SEQ_COUNTRY&lt;/param&gt; &lt;/generator&gt; &lt;/id&gt; &lt;natural-id mutable="true"&gt; &lt;property name="name" column="COUNTRY_NAME" type="java.lang.String"/&gt; &lt;/natural-id&gt; &lt;list name="addressElementList" table="tuto.ADDRESS_ELEMENT" lazy="false"&gt; &lt;key foreign-key="country_address_element_fk"&gt; &lt;column name="COUNTRY_ID" not-null="true"/&gt; &lt;/key&gt; &lt;list-index&gt; &lt;column name="ADDRESS_ELEMENT_POS" not-null="true" /&gt; &lt;/list-index&gt; &lt;one-to-many class="AddressElement"/&gt; &lt;/list&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; &lt;hibernate-mapping package="org.devtutos.tuto5.domaine"&gt; &lt;class name="AddressElement" table="tuto.ADDRESS_ELEMENT"&gt; &lt;id name="id" type="java.lang.Long" column="ADDRESS_ELEMENT_ID" unsaved-value="null"&gt; &lt;generator class="native"&gt; &lt;param name="sequence"&gt;tuto.SEQ_ADDRESS_ELEMENT&lt;/param&gt; &lt;/generator&gt; &lt;/id&gt; &lt;property name="line" column="ADDRESS_ELEMENT_LINE" not-null="true" type="java.lang.Integer" /&gt; &lt;property name="name" column="ADDRESS_ELEMENT_NAME" not-null="true" type="java.lang.String" /&gt; &lt;property name="mask" column="ADDRESS_ELEMENT_TYPE_MASK" not-null="true" type="java.lang.String" /&gt; &lt;property name="pos" column="ADDRESS_ELEMENT_POS" not-null="true" type="java.lang.Integer" /&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; </code></pre> <p>This my code:</p> <pre><code>criteria = getSessionFactory().getCurrentSession().createCriteria(Country.class); criteria.add(Restrictions.eq("name", countryName)); criteria.setFetchMode("addressElementList",FetchMode.JOIN); Country country = (Country) criteria.list().get(0); if (country == null) { logger.log(Level.INFO, "ERREUR DE COHERENCE INTERNE : Pays '".concat(countryName).concat("'non trouvé:")); } else { logger.log(Level.INFO, "Pays trouvé."); logger.log(Level.INFO, "Nom du Pays :".concat(country.getName())); logger.log(Level.INFO, "Code du Pays :".concat(String.valueOf(country.getId()))); liste = country.getAddressElementList(); logger.log(Level.INFO, "Taille de la liste des éléments d'adresse :".concat(String.valueOf(liste.size()))); for (AddressElement elem : liste) { if (elem == null) {logger.log(Level.INFO, "L'élément d'adresse est null.");} logger.log(Level.INFO, "Element de la liste : ID = ".concat(String.valueOf(elem.getId()))); **** Line of the error logger.log(Level.INFO, "Element de la liste : POS = ".concat(String.valueOf(elem.getPos()))); logger.log(Level.INFO, "Element de la liste : NOM = ".concat(elem.getName())); } } </code></pre> <p>This is my log :</p> <pre><code>Hibernate: select this_.COUNTRY_ID as COUNTRY1_2_1_, this_.COUNTRY_NAME as COUNTRY2_2_1_, addressele2_.COUNTRY_ID as COUNTRY6_2_3_, addressele2_.ADDRESS_ELEMENT_ID as ADDRESS1_3_, addressele2_.ADDRESS_ELEMENT_POS as ADDRESS5_3_, addressele2_.ADDRESS_ELEMENT_ID as ADDRESS1_0_0_, addressele2_.ADDRESS_ELEMENT_LINE as ADDRESS2_0_0_, addressele2_.ADDRESS_ELEMENT_NAME as ADDRESS3_0_0_, addressele2_.ADDRESS_ELEMENT_TYPE_MASK as ADDRESS4_0_0_, addressele2_.ADDRESS_ELEMENT_POS as ADDRESS5_0_0_ from tuto.COUNTRY this_ left outer join tuto.ADDRESS_ELEMENT addressele2_ on this_.COUNTRY_ID=addressele2_.COUNTRY_ID where this_.COUNTRY_NAME=? 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Pays trouvé. 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Nom du Pays :FRANCE 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Code du Pays :1 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Taille de la liste des éléments d'adresse :4 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: L'élément d'adresse est null. 27 déc. 2012 16:19:09 org.apache.catalina.core.StandardWrapperValve invoke GRAVE: Servlet.service() for servlet [tuto5] in context with path [/tuto-5] threw exception [Request processing failed; nested exception is org.springframework.webflow.execution.ActionExecutionException: Exception thrown executing [AnnotatedAction@3f610944 targetAction org.devtutos.tuto5.mvc.webflow.action.receptionAction@4dc6bbd3, attributes = map['method' -&gt; 'enregistrerLUtilisateur']] in state 'enregistrerLUtilisateur' of flow 'reception' -- action execution attributes were 'map[[empty]]'] with root cause java.lang.NullPointerException at org.devtutos.tuto5.dao.CountryHibernate.getCountryByName(CountryHibernate.java:103) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:319) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) ... at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) </code></pre> <p>I can't access the information of address elements from a country. I tried several things: I turned on lazy mode and specified a fetch mode with JOIN but it doesn't work. The most surprising is the list is populated (there are 4 elements) and the following code runs well (So, the information is in the database, setters and getters work):</p> <pre><code>logger.log(Level.INFO, "Lecture de tous les éléments d'adresse."); criteria = getSessionFactory().getCurrentSession().createCriteria(AddressElement.class); liste = criteria.list(); logger.log(Level.INFO, "Taille de la liste des éléments d'adresse : ".concat(String.valueOf(liste.size()))); for (AddressElement elem : liste){ if (elem == null) {logger.log(Level.INFO, "L'élément d'adresse est null.");} logger.log(Level.INFO, "Element de la liste : ID = ".concat(String.valueOf(elem.getId()))); logger.log(Level.INFO, "Element de la liste : POS = ".concat(String.valueOf(elem.getPos()))); logger.log(Level.INFO, "Element de la liste : NOM = ".concat(elem.getName())); } </code></pre> <p>These is the result of this code:</p> <pre><code>INFO: Lecture de tous les éléments d'adresse. Hibernate: select this_.ADDRESS_ELEMENT_ID as ADDRESS1_0_0_, this_.ADDRESS_ELEMENT_LINE as ADDRESS2_0_0_, this_.ADDRESS_ELEMENT_NAME as ADDRESS3_0_0_, this_.ADDRESS_ELEMENT_TYPE_MASK as ADDRESS4_0_0_, this_.ADDRESS_ELEMENT_POS as ADDRESS5_0_0_ from tuto.ADDRESS_ELEMENT this_ 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Taille de la liste des éléments d'adresse : 6 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : ID = 1 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : POS = 1 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : NOM = Code Postal 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : ID = 2 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : POS = 2 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : NOM = Ville 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : ID = 3 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : POS = 3 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : NOM = Batiment 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : ID = 4 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : POS = 1 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : NOM = District 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : ID = 5 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : POS = 2 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : NOM = Zone 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : ID = 6 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : POS = 1 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName INFO: Element de la liste : NOM = City 27 déc. 2012 16:19:09 org.devtutos.tuto5.dao.CountryHibernate getCountryByName </code></pre> <p>I noticed in my first execution that the size of my list is wrong (4 instead of 3). In my example, the value of <code>countryName</code> is "FRANCE". This is the content of my tables:</p> <p>COUNTRY:</p> <pre><code>COUNTRY_ID CONTRY_NAME 1 "FRANCE" 2 "HYPERION" 3 "ATLANTIS" </code></pre> <p>ADDRESS_ELEMENT:</p> <pre><code>ADDRESS_ELEMENT_ID COUNTRY_ID ADDRESS_ELEMENT_POS ADDRESS_ELEMENT_NAME ADDRESS_ELEMENT_MASK ADDRESS_ELEMENT_LINE 1 1 1 "Code Postal" "\d{5}" 1 2 1 2 "Ville" "[A-Z\-]{1,50}" 1 3 1 3 "Batiment" "[A-F]" 1 4 2 1 "District" "[A-Z]{1,20}" 1 5 2 2 "Zone" "[A-5]{1,5}" 2 6 3 1 "City" "[A-Z]{1,9}" 1 </code></pre> <p>What am I doing wrong? I don't understand why <code>elem</code> is null in the first execution. Can somebody help me?</p> <p>Thanks in advance.</p> <p>Have a happy new year. ;-)</p>
 

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