Adding Interfaces to families of operators; permits much cleaner UDFs

* New interface IOperatorAWithB for (geom, geom) -> geom
* Applied it to Intersection, Difference, SymmetricDifference, and Union
More to come.

Author: Philip (flip) Kromer

src/main/java/com/esri/core/geometry/IOperatorAWithB.java

@@ -0,0 +1,45 @@
+/*
+ Copyright 1995-2013 Esri
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+ For additional information, contact:
+ Environmental Systems Research Institute, Inc.
+ Attn: Contracts Dept
+ 380 New York Street
+ Redlands, California, USA 92373
+
+ email: contracts@esri.com
+ */
+package com.esri.core.geometry;
+
+import com.esri.core.geometry.Geometry;
+import com.esri.core.geometry.SpatialReference;
+import com.esri.core.geometry.ProgressTracker;
+
+/**
+ * Interface for operators that act on two geometries to produce a new geometry as result.
+ */
+public interface IOperatorAWithB {
+
+	/**
+	 * Operation on two geometries, returning a third. Examples include
+	 * Intersection, Difference, and so forth.
+     *
+	 * @param geom1 and geom2 are the geometry instances to be operated on.
+	 *
+	 */
+	public Geometry execute(Geometry geom1, Geometry geom2,
+        SpatialReference sr, ProgressTracker progressTracker);
+
+}

src/main/java/com/esri/core/geometry/OperatorDifference.java

@@ -25,11 +25,12 @@
 package com.esri.core.geometry;
 
 import com.esri.core.geometry.Operator.Type;
+import com.esri.core.geometry.IOperatorAWithB;
 
 /**
  * Difference of geometries.
  */
-public abstract class OperatorDifference extends Operator {
+public abstract class OperatorDifference extends Operator implements IOperatorAWithB {
 
 	@Override
 	public Type getType() {

src/main/java/com/esri/core/geometry/OperatorIntersection.java

@@ -25,11 +25,12 @@
 package com.esri.core.geometry;
 
 import com.esri.core.geometry.Operator.Type;
+import com.esri.core.geometry.IOperatorAWithB;
 
 /**
  *Intersection of geometries by a given geometry.
  */
-public abstract class OperatorIntersection extends Operator {
+public abstract class OperatorIntersection extends Operator implements IOperatorAWithB {
 	@Override
 	public Type getType() {
 		return Type.Intersection;

src/main/java/com/esri/core/geometry/OperatorSymmetricDifference.java

@@ -24,12 +24,13 @@
 package com.esri.core.geometry;
 
 import com.esri.core.geometry.Operator.Type;
+import com.esri.core.geometry.IOperatorAWithB;
 
 /**
  * Symmetric difference (XOR) operation between geometries. 
  *
  */
-public abstract class OperatorSymmetricDifference extends Operator {
+public abstract class OperatorSymmetricDifference extends Operator implements IOperatorAWithB {
 	@Override
 	public Type getType() {
 		return Type.Difference;

src/main/java/com/esri/core/geometry/OperatorUnion.java

@@ -25,13 +25,14 @@
 package com.esri.core.geometry;
 
 import com.esri.core.geometry.Operator.Type;
+import com.esri.core.geometry.IOperatorAWithB;
 
 /**
  * 
  * Union of geometries.
  *
  */
-public abstract class OperatorUnion extends Operator {
+public abstract class OperatorUnion extends Operator implements IOperatorAWithB {
 	@Override
 	public Type getType() {
 		return Type.Union;