From a6da64241640359837d4ebdf0aa42216b42f926a Mon Sep 17 00:00:00 2001
From: Jake Swenson <jswenson@godaddy.com>
Date: Sun, 4 Dec 2016 10:04:26 -0800
Subject: [PATCH] Adding support for custom path functions

Adding a configuration value for a path function factory
---
 .../com/jayway/jsonpath/Configuration.java    | 55 ++++++++++++++++++-
 .../function/JsonPathFunctionFactory.java     | 24 ++++++++
 .../function/MapJsonPathFunctionFactory.java  | 30 ++++++++++
 .../function/PathFunctionFactory.java         | 16 ++----
 .../internal/path/FunctionPathToken.java      |  2 +-
 5 files changed, 111 insertions(+), 16 deletions(-)
 create mode 100644 json-path/src/main/java/com/jayway/jsonpath/internal/function/JsonPathFunctionFactory.java
 create mode 100644 json-path/src/main/java/com/jayway/jsonpath/internal/function/MapJsonPathFunctionFactory.java

diff --git a/json-path/src/main/java/com/jayway/jsonpath/Configuration.java b/json-path/src/main/java/com/jayway/jsonpath/Configuration.java
index 1a591ea8d..b4aa86596 100644
--- a/json-path/src/main/java/com/jayway/jsonpath/Configuration.java
+++ b/json-path/src/main/java/com/jayway/jsonpath/Configuration.java
@@ -15,6 +15,10 @@
 package com.jayway.jsonpath;
 
 import com.jayway.jsonpath.internal.DefaultsImpl;
+import com.jayway.jsonpath.internal.function.JsonPathFunctionFactory;
+import com.jayway.jsonpath.internal.function.MapJsonPathFunctionFactory;
+import com.jayway.jsonpath.internal.function.PathFunction;
+import com.jayway.jsonpath.internal.function.PathFunctionFactory;
 import com.jayway.jsonpath.spi.json.JsonProvider;
 import com.jayway.jsonpath.spi.mapper.MappingProvider;
 
@@ -23,6 +27,8 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Set;
 
 import static com.jayway.jsonpath.internal.Utils.notNull;
@@ -55,16 +61,24 @@ private static Defaults getEffectiveDefaults(){
     private final MappingProvider mappingProvider;
     private final Set<Option> options;
     private final Collection<EvaluationListener> evaluationListeners;
-
-    private Configuration(JsonProvider jsonProvider, MappingProvider mappingProvider, EnumSet<Option> options, Collection<EvaluationListener> evaluationListeners) {
+    private final JsonPathFunctionFactory jsonPathFunctionFactory;
+
+    private Configuration(
+            JsonProvider jsonProvider,
+            MappingProvider mappingProvider,
+            EnumSet<Option> options,
+            Collection<EvaluationListener> evaluationListeners,
+            final JsonPathFunctionFactory jsonPathFunctionFactory) {
         notNull(jsonProvider, "jsonProvider can not be null");
         notNull(mappingProvider, "mappingProvider can not be null");
         notNull(options, "setOptions can not be null");
         notNull(evaluationListeners, "evaluationListeners can not be null");
+        notNull(jsonPathFunctionFactory, "jsonPathFunctionFactory can not be null");
         this.jsonProvider = jsonProvider;
         this.mappingProvider = mappingProvider;
         this.options = Collections.unmodifiableSet(options);
         this.evaluationListeners = Collections.unmodifiableCollection(evaluationListeners);
+        this.jsonPathFunctionFactory = jsonPathFunctionFactory;
     }
 
     /**
@@ -127,6 +141,14 @@ public MappingProvider mappingProvider() {
         return mappingProvider;
     }
 
+    /**
+     * Returns {@link com.jayway.jsonpath.internal.function.JsonPathFunctionFactory} used by this configuration
+     * @return pathFunctionFactory used
+     */
+    public JsonPathFunctionFactory pathFunctionFactory() {
+        return this.jsonPathFunctionFactory;
+    }
+
     /**
      * Creates a new configuration by adding the new options to the options used in this configuration.
      * @param options options to add
@@ -187,11 +209,16 @@ public static ConfigurationBuilder builder() {
      */
     public static class ConfigurationBuilder {
 
+        private static final JsonPathFunctionFactory DEFAULT_FUNCTION_FACTORY =
+                new MapJsonPathFunctionFactory(PathFunctionFactory.FUNCTIONS);
+
         private JsonProvider jsonProvider;
         private MappingProvider mappingProvider;
         private EnumSet<Option> options = EnumSet.noneOf(Option.class);
         private Collection<EvaluationListener> evaluationListener = new ArrayList<EvaluationListener>();
 
+        private JsonPathFunctionFactory jsonPathFunctionFactory = DEFAULT_FUNCTION_FACTORY;
+
         public ConfigurationBuilder jsonProvider(JsonProvider provider) {
             this.jsonProvider = provider;
             return this;
@@ -224,6 +251,28 @@ public ConfigurationBuilder evaluationListener(Collection<EvaluationListener> li
             return this;
         }
 
+        public ConfigurationBuilder pathFunctionFactory(final JsonPathFunctionFactory jsonPathFunctionFactory) {
+            if(jsonPathFunctionFactory == null) {
+                this.jsonPathFunctionFactory = DEFAULT_FUNCTION_FACTORY;
+            }
+            else {
+                this.jsonPathFunctionFactory = jsonPathFunctionFactory;
+            }
+            return this;
+        }
+
+        public ConfigurationBuilder pathFunctions(final Map<String, Class<? extends PathFunction>> functions) {
+            if(functions == null) {
+                this.jsonPathFunctionFactory = DEFAULT_FUNCTION_FACTORY;
+            }
+            else {
+                this.jsonPathFunctionFactory = new MapJsonPathFunctionFactory(
+                        new HashMap<String, Class<? extends PathFunction>>(functions)
+                );
+            }
+            return this;
+        }
+
         public Configuration build() {
             if (jsonProvider == null || mappingProvider == null) {
                 final Defaults defaults = getEffectiveDefaults();
@@ -234,7 +283,7 @@ public Configuration build() {
                     mappingProvider = defaults.mappingProvider();
                 }
             }
-            return new Configuration(jsonProvider, mappingProvider, options, evaluationListener);
+            return new Configuration(jsonProvider, mappingProvider, options, evaluationListener, jsonPathFunctionFactory);
         }
     }
 
diff --git a/json-path/src/main/java/com/jayway/jsonpath/internal/function/JsonPathFunctionFactory.java b/json-path/src/main/java/com/jayway/jsonpath/internal/function/JsonPathFunctionFactory.java
new file mode 100644
index 000000000..9982c20c4
--- /dev/null
+++ b/json-path/src/main/java/com/jayway/jsonpath/internal/function/JsonPathFunctionFactory.java
@@ -0,0 +1,24 @@
+package com.jayway.jsonpath.internal.function;
+
+import com.jayway.jsonpath.InvalidPathException;
+
+import java.util.Map;
+
+public interface JsonPathFunctionFactory {
+    /**
+     * Returns the function by name or throws InvalidPathException if function not found.
+     *
+     * @see #FUNCTIONS
+     * @see PathFunction
+     *
+     * @param name
+     *      The name of the function
+     *
+     * @return
+     *      The implementation of a function
+     *
+     * @throws InvalidPathException
+     */
+    PathFunction newFunction(final String name) throws InvalidPathException;
+}
+
diff --git a/json-path/src/main/java/com/jayway/jsonpath/internal/function/MapJsonPathFunctionFactory.java b/json-path/src/main/java/com/jayway/jsonpath/internal/function/MapJsonPathFunctionFactory.java
new file mode 100644
index 000000000..2c786f71d
--- /dev/null
+++ b/json-path/src/main/java/com/jayway/jsonpath/internal/function/MapJsonPathFunctionFactory.java
@@ -0,0 +1,30 @@
+package com.jayway.jsonpath.internal.function;
+
+import com.jayway.jsonpath.InvalidPathException;
+
+import java.util.Map;
+
+public class MapJsonPathFunctionFactory implements JsonPathFunctionFactory {
+
+    private final Map<String, Class<? extends PathFunction>> pathFunctionMap;
+
+    public MapJsonPathFunctionFactory(
+            final Map<String, Class<? extends PathFunction>> pathFunctionMap) {
+
+        this.pathFunctionMap = pathFunctionMap;
+    }
+
+    @Override
+    public PathFunction newFunction(final String name) throws InvalidPathException {
+        Class functionClazz = pathFunctionMap.get(name);
+        if(functionClazz == null){
+            throw new InvalidPathException("Function with name: " + name + " does not exists.");
+        } else {
+            try {
+                return (PathFunction)functionClazz.newInstance();
+            } catch (Exception e) {
+                throw new InvalidPathException("Function of name: " + name + " cannot be created", e);
+            }
+        }
+    }
+}
diff --git a/json-path/src/main/java/com/jayway/jsonpath/internal/function/PathFunctionFactory.java b/json-path/src/main/java/com/jayway/jsonpath/internal/function/PathFunctionFactory.java
index 9688ebb86..c33a1f8dc 100644
--- a/json-path/src/main/java/com/jayway/jsonpath/internal/function/PathFunctionFactory.java
+++ b/json-path/src/main/java/com/jayway/jsonpath/internal/function/PathFunctionFactory.java
@@ -25,11 +25,11 @@
  */
 public class PathFunctionFactory {
 
-    public static final Map<String, Class> FUNCTIONS;
+    public static final Map<String, Class<? extends PathFunction>> FUNCTIONS;
 
     static {
         // New functions should be added here and ensure the name is not overridden
-        Map<String, Class> map = new HashMap<String, Class>();
+        Map<String, Class<? extends PathFunction>> map = new HashMap<String, Class<? extends PathFunction>>();
 
         // Math Functions
         map.put("avg", Average.class);
@@ -64,16 +64,8 @@ public class PathFunctionFactory {
      *
      * @throws InvalidPathException
      */
+    @Deprecated
     public static PathFunction newFunction(String name) throws InvalidPathException {
-        Class functionClazz = FUNCTIONS.get(name);
-        if(functionClazz == null){
-            throw new InvalidPathException("Function with name: " + name + " does not exists.");
-        } else {
-            try {
-                return (PathFunction)functionClazz.newInstance();
-            } catch (Exception e) {
-                throw new InvalidPathException("Function of name: " + name + " cannot be created", e);
-            }
-        }
+        return new MapJsonPathFunctionFactory(FUNCTIONS).newFunction(name);
     }
 }
diff --git a/json-path/src/main/java/com/jayway/jsonpath/internal/path/FunctionPathToken.java b/json-path/src/main/java/com/jayway/jsonpath/internal/path/FunctionPathToken.java
index 8e9055ed8..7e2c37ccd 100644
--- a/json-path/src/main/java/com/jayway/jsonpath/internal/path/FunctionPathToken.java
+++ b/json-path/src/main/java/com/jayway/jsonpath/internal/path/FunctionPathToken.java
@@ -33,7 +33,7 @@ public FunctionPathToken(String pathFragment, List<Parameter> parameters) {
 
     @Override
     public void evaluate(String currentPath, PathRef parent, Object model, EvaluationContextImpl ctx) {
-        PathFunction pathFunction = PathFunctionFactory.newFunction(functionName);
+        PathFunction pathFunction = ctx.configuration().pathFunctionFactory().newFunction(functionName);
         evaluateParameters(currentPath, parent, model, ctx);
         Object result = pathFunction.invoke(currentPath, parent, model, ctx, functionParams);
         ctx.addResult(currentPath + "." + functionName, parent, result);