ENH: support for multiple indices added

src/main/java/com/avaje/ebean/annotation/Index.java

@@ -6,7 +6,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * An annotation for declaring an index on a single column.
+ * An annotation for declaring an index.
  *
  * @author rvbiljouw
  */
@@ -27,6 +27,9 @@ public @interface Index {
   /**
    * When placed on the class (rather than field) you can specify the columns
    * to include in the index in order.
+   * 
+   * Wnen placed on a field, and columnNames are specified, the field-column has to be included.
+   * You can use "${fa}" for alias
    */
   String[] columnNames() default {};
 

src/main/java/com/avaje/ebean/annotation/Indices.java

@@ -0,0 +1,20 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+/**
+ * An annotation for declaring multiple indices at class or field level.
+ * 
+ * @author Roland Praml, FOCONIS AG
+ */
+@Target({ElementType.TYPE, ElementType.FIELD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Indices {
+
+  /**
+   * Array with {@link Index} definitions.
+   */
+  Index[] indices() default {};
+}

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/AnnotationClass.java

@@ -7,6 +7,7 @@ import com.avaje.ebean.annotation.Draftable;
 import com.avaje.ebean.annotation.DraftableElement;
 import com.avaje.ebean.annotation.History;
 import com.avaje.ebean.annotation.Index;
+import com.avaje.ebean.annotation.Indices;
 import com.avaje.ebean.annotation.ReadAudit;
 import com.avaje.ebean.annotation.UpdateMode;
 import com.avaje.ebean.annotation.View;
@@ -118,6 +119,13 @@ public class AnnotationClass extends AnnotationParser {
       descriptor.setName("Embeddable:" + cls.getSimpleName());
     }
 
+    Indices indices = AnnotationBase.findAnnotation(cls, Indices.class);
+    if (indices != null) {
+      for (Index index: indices.indices()) {
+        descriptor.addIndex(new IndexDefinition(index.columnNames(), index.name(), index.unique()));
+      }
+    }
+
     Index index = AnnotationBase.findAnnotation(cls,Index.class);
     if (index != null) {
       descriptor.addIndex(new IndexDefinition(index.columnNames(), index.name(), index.unique()));

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/AnnotationFields.java

@@ -310,15 +310,46 @@ public class AnnotationFields extends AnnotationParser {
       }
     }
 
+    Indices indices =  get(prop, Indices.class);
+    if (indices != null) {
+      for (Index index: indices.indices()) {
+        addIndex(prop, index);
+      }
+    }
+    
     Index index = get(prop, Index.class);
     if (index != null) {
-      if (hasRelationshipItem(prop)) {
-        throw new RuntimeException("Can't use Index on foreign key relationships.");
-      }
-      descriptor.addIndex(new IndexDefinition(prop.getDbColumn(), index.name(), index.unique()));
+      addIndex(prop, index);
     }
   }
 
+  private void addIndex(DeployBeanProperty prop, Index index) {
+    String[] columnNames;
+    if (index.columnNames() == null || index.columnNames().length == 0) {
+      columnNames = new String[] {prop.getDbColumn()};
+    } else {
+      columnNames = new String[index.columnNames().length];
+      int i=0;
+      int found = 0;
+      for (String colName : index.columnNames()) {
+        if (colName.equals("${fa}") || colName.equals(prop.getDbColumn())) {
+          columnNames[i++] = prop.getDbColumn();
+          found++;
+        } else {
+          columnNames[i++] = colName;
+        }
+      }
+      if (found != 1) {
+        throw new RuntimeException("DB-columname has to be specified exactly one time in columnNames.");
+      }
+    }
+    
+    if (columnNames.length == 1 && hasRelationshipItem(prop)) {
+      throw new RuntimeException("Can't use Index on foreign key relationships.");
+    }
+    descriptor.addIndex(new IndexDefinition(columnNames, index.name(), index.unique()));
+  }
+
   private void readJsonAnnotations(DeployBeanProperty prop) {
     if (jacksonAnnotationsPresent) {
       com.fasterxml.jackson.annotation.JsonIgnore jsonIgnore = get(prop, com.fasterxml.jackson.annotation.JsonIgnore.class);