Only import contact entry keys once

ccm-cms/src/main/java/org/librecms/assets/ContactEntry.java

@@ -18,8 +18,7 @@
  */
 package org.librecms.assets;
 
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.annotation.JsonIdentityReference;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import org.hibernate.envers.Audited;
 
 import java.io.Serializable;
@@ -65,6 +64,7 @@ public class ContactEntry implements Serializable {
 //    @Column(name = "ENTRY_KEY", length = 255, nullable = false)
     @OneToOne
     @JoinColumn(name = "CONTACT_ENTRY_KEY_ID")
+    @JsonIdentityReference(alwaysAsId = true)
     private ContactEntryKey key;
 
     /**

ccm-cms/src/main/java/org/librecms/assets/ContactEntryKey.java

@@ -18,6 +18,8 @@
  */
 package org.librecms.assets;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.ObjectIdGenerators;
 import org.hibernate.envers.Audited;
 import org.libreccm.l10n.LocalizedString;
 
@@ -52,6 +54,12 @@ import static org.librecms.CmsConstants.*;
         query = "SELECT k FROM ContactEntryKey k WHERE k.entryKey = :entryKey"
     )
 })
+@JsonIdentityInfo(
+    generator = ObjectIdGenerators.PropertyGenerator.class,
+    resolver = ContactEntryKeyResolver.class,
+    property = "entryKey",
+    scope = ContactEntryKey.class
+)
 public class ContactEntryKey
     implements Comparable<ContactEntryKey>, Serializable {
 

ccm-cms/src/main/java/org/librecms/assets/ContactEntryKeyResolver.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2022 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.librecms.assets;
+
+import com.fasterxml.jackson.annotation.ObjectIdGenerator;
+import com.fasterxml.jackson.annotation.ObjectIdResolver;
+import org.libreccm.cdi.utils.CdiUtil;
+
+import java.io.Serializable;
+import java.util.Optional;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+public class ContactEntryKeyResolver implements Serializable, ObjectIdResolver {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public void bindItem(
+        final ObjectIdGenerator.IdKey id,
+        final Object object
+    ) {
+        // According to the Jackson JavaDoc, this method can be used to keep
+        // track of objects directly in a resolver implementation. We don't need
+        // this here therefore this method is empty.
+    }
+
+    @Override
+    public Object resolveId(final ObjectIdGenerator.IdKey id) {
+        final ContactEntryKeyRepository keyRepo = CdiUtil
+            .createCdiUtil()
+            .findBean(ContactEntryKeyRepository.class);
+        final Optional<ContactEntryKey> result = keyRepo.findByEntryKey(
+            id.key.toString()
+        );
+        if (result.isPresent()) {
+            return result.get();
+        } else {
+            final ContactEntryKey key = new ContactEntryKey();
+            key.setEntryKey(id.key.toString());
+            keyRepo.save(key);
+            return key;
+        }
+    }
+
+    @Override
+    public ObjectIdResolver newForDeserialization(final Object context) {
+        return new ContactEntryKeyResolver();
+    }
+
+    @Override
+    public boolean canUseFor(final ObjectIdResolver resolverType) {
+        return resolverType instanceof ContactEntryKeyResolver;
+    }
+
+}