AggregationDataStore: Schema

elide-core/src/main/java/com/yahoo/elide/core/EntityDictionary.java

@@ -1214,6 +1214,36 @@ public boolean hasBinding(Class<?> cls) {
         return bindJsonApiToEntity.contains(cls);
     }
 
+    /**
+     * Returns whether or not a specified annotation is present on an entity field or its corresponding method.
+     *
+     * @param fieldName  The entity field
+     * @param annotationClass  The provided annotation class
+     *
+     * @param <A>  The type of the {@code annotationClass}
+     *
+     * @return {@code true} if the field is annotated by the {@code annotationClass}
+     */
+    public <A extends Annotation> boolean attributeOrRelationAnnotationExists(
+            Class<?> cls,
+            String fieldName,
+            Class<A> annotationClass
+    ) {
+        return getAttributeOrRelationAnnotation(cls, annotationClass, fieldName) != null;
+    }
+
+    /**
+     * Returns whether or not a specified field exists in an entity.
+     *
+     * @param cls  The entity
+     * @param fieldName  The provided field to check
+     *
+     * @return {@code true} if the field exists in the entity
+     */
+    public boolean isValidField(Class<?> cls, String fieldName) {
+        return getAllFields(cls).contains(fieldName);
+    }
+
     /**
      * Binds the entity class if not yet bound.
      * @param entityClass the class to bind.

elide-core/src/test/java/com/yahoo/elide/core/EntityDictionaryTest.java

@@ -47,6 +47,7 @@
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
+import javax.persistence.OneToOne;
 import javax.persistence.Transient;
 
 public class EntityDictionaryTest extends EntityDictionary {
@@ -475,4 +476,16 @@ public void testBadLookupEntityClass() {
         Assert.assertThrows(IllegalArgumentException.class, () -> lookupEntityClass(null));
         Assert.assertThrows(IllegalArgumentException.class, () -> lookupEntityClass(Object.class));
     }
+
+    @Test
+    public void testAttributeOrRelationAnnotationExists() {
+        Assert.assertTrue(attributeOrRelationAnnotationExists(Job.class, "jobId", Id.class));
+        Assert.assertFalse(attributeOrRelationAnnotationExists(Job.class, "title", OneToOne.class));
+    }
+
+    @Test
+    public void testIsValidField() {
+        Assert.assertTrue(isValidField(Job.class, "title"));
+        Assert.assertFalse(isValidField(Job.class, "foo"));
+    }
 }

elide-datastore/elide-datastore-aggregation/pom.xml

@@ -44,10 +44,36 @@
             <groupId>com.yahoo.elide</groupId>
             <artifactId>elide-core</artifactId>
         </dependency>
+
+        <!-- JPA -->
+        <dependency>
+            <groupId>org.hibernate.javax.persistence</groupId>
+            <artifactId>hibernate-jpa-2.1-api</artifactId>
+            <version>1.0.0.Final</version>
+        </dependency>
+
+        <!-- Test -->
+        <dependency>
+            <groupId>org.testng</groupId>
+            <artifactId>testng</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>build-helper-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>

elide-datastore/elide-datastore-aggregation/src/main/java/com/yahoo/elide/datastores/aggregation/Column.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2019, Yahoo Inc.
+ * Licensed under the Apache License, Version 2.0
+ * See LICENSE file in project root for terms.
+ */
+package com.yahoo.elide.datastores.aggregation;
+
+import com.yahoo.elide.datastores.aggregation.annotation.Meta;
+import com.yahoo.elide.datastores.aggregation.dimension.Dimension;
+import com.yahoo.elide.datastores.aggregation.metric.Metric;
+
+import lombok.Getter;
+
+import java.util.Objects;
+
+/**
+ * Base class that offers common components between {@link Metric} and {@link Dimension}.
+ */
+public abstract class Column {
+
+    @Getter
+    protected final String name;
+    @Getter
+    protected final String longName;
+    @Getter
+    protected final String description;
+    @Getter
+    protected final Class<?> dataType;
+
+    /**
+     * Constructor.
+     *
+     * @param field  The entity field or relation that this {@link Column} represents
+     * @param annotation  Provides static meta data about this {@link Column}
+     * @param fieldType  The Java type for this entity field or relation
+     *
+     * @throws NullPointerException if {@code field} or {@code fieldType} is {@code null}
+     */
+    public Column(String field, Meta annotation, Class<?> fieldType) {
+        this.name = Objects.requireNonNull(field, "field");
+        this.longName = annotation == null || annotation.longName().isEmpty() ? field : annotation.longName();
+        this.description = annotation == null || annotation.description().isEmpty() ? field : annotation.description();
+        this.dataType = Objects.requireNonNull(fieldType, "fieldType");
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other) {
+            return true;
+        }
+        if (other == null || getClass() != other.getClass()) {
+            return false;
+        }
+        final Column column = (Column) other;
+
+        return getName().equals(column.getName())
+                && getLongName().equals(column.getLongName())
+                && getDescription().equals(column.getDescription())
+                && getDataType().equals(column.getDataType());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getName(), getLongName(), getDescription(), getDataType());
+    }
+}