Added convert method for path value in-situ conversion.

json-path/src/main/java/com/jayway/jsonpath/JsonPath.java

@@ -15,12 +15,7 @@
 package com.jayway.jsonpath;
 
 
-import com.jayway.jsonpath.internal.EvaluationContext;
+import com.jayway.jsonpath.internal.*;
-import com.jayway.jsonpath.internal.JsonReader;
-import com.jayway.jsonpath.internal.Path;
-import com.jayway.jsonpath.internal.PathCompiler;
-import com.jayway.jsonpath.internal.PathRef;
-import com.jayway.jsonpath.internal.Utils;
 import com.jayway.jsonpath.spi.json.JsonProvider;
 
 import java.io.File;
@@ -218,6 +213,17 @@ public class JsonPath {
         return resultByConfiguration(jsonObject, configuration, evaluationContext);
     }
 
+    public <T> T convert(Object jsonObject, ValueConverter valueConverter, Configuration configuration) {
+        notNull(jsonObject, "json can not be null");
+        notNull(configuration, "configuration can not be null");
+        EvaluationContext evaluationContext = path.evaluate(jsonObject, jsonObject, configuration, true);
+        for (PathRef updateOperation : evaluationContext.updateOperations()) {
+            updateOperation.convert(valueConverter, configuration);
+        }
+        return resultByConfiguration(jsonObject, configuration, evaluationContext);
+    }
+
+
     /**
      * Deletes the object this path points to in the provided jsonObject
      *

json-path/src/main/java/com/jayway/jsonpath/WriteContext.java

@@ -14,6 +14,8 @@
  */
 package com.jayway.jsonpath;
 
+import com.jayway.jsonpath.internal.ValueConverter;
+
 public interface WriteContext {
 
     /**
@@ -56,6 +58,25 @@ public interface WriteContext {
      */
     DocumentContext set(JsonPath path, Object newValue);
 
+    /**
+     * Converts the value on the given path.
+     *
+     * @param path              path to be converted set
+     * @param valueConverter    Converter object to be invoked (or lambda:))
+     * @param filters           filters
+     * @return a document context
+     */
+    DocumentContext convert(String path, ValueConverter valueConverter, Predicate... filters);
+
+    /**
+     * Converts the value on the given path.
+     *
+     * @param path              path to be converted set
+     * @param valueConverter    Converter object to be invoked (or lambda:))
+     * @return a document context
+     */
+    DocumentContext convert(JsonPath path, ValueConverter valueConverter);
+
     /**
      * Deletes the given path
      *

json-path/src/main/java/com/jayway/jsonpath/internal/JsonReader.java

@@ -33,6 +33,7 @@ import java.io.InputStream;
 import java.util.List;
 
 import static com.jayway.jsonpath.JsonPath.compile;
+import static com.jayway.jsonpath.JsonPath.parse;
 import static com.jayway.jsonpath.internal.Utils.notEmpty;
 import static com.jayway.jsonpath.internal.Utils.notNull;
 
@@ -194,6 +195,18 @@ public class JsonReader implements ParseContext, DocumentContext {
         return this;
     }
 
+    @Override
+    public DocumentContext convert(String path, ValueConverter valueConverter, Predicate... filters) {
+        convert(compile(path, filters), valueConverter);
+        return this;
+    }
+
+    @Override
+    public DocumentContext convert(JsonPath path, ValueConverter valueConverter) {
+        path.convert(json, valueConverter, configuration);
+        return this;
+    }
+
     @Override
     public DocumentContext delete(String path, Predicate... filters) {
         return delete(compile(path, filters));

json-path/src/main/java/com/jayway/jsonpath/internal/PathRef.java

@@ -17,6 +17,9 @@ public abstract class PathRef implements Comparable<PathRef>  {
         @Override
         public void set(Object newVal, Configuration configuration) {}
 
+        @Override
+        public void convert(ValueConverter valueConverter, Configuration configuration) {}
+
         @Override
         public void delete(Configuration configuration) {}
 
@@ -42,6 +45,8 @@ public abstract class PathRef implements Comparable<PathRef>  {
 
     public abstract void set(Object newVal, Configuration configuration);
 
+    public abstract void convert(ValueConverter valueConverter, Configuration configuration);
+
     public abstract void delete(Configuration configuration);
 
     public abstract void add(Object newVal, Configuration configuration);
@@ -103,6 +108,10 @@ public abstract class PathRef implements Comparable<PathRef>  {
             throw new InvalidModificationException("Invalid delete operation");
         }
 
+        public void convert(ValueConverter valueConverter, Configuration configuration){
+            throw new InvalidModificationException("Invalid convert operation");
+        }
+
         @Override
         public void delete(Configuration configuration) {
             throw new InvalidModificationException("Invalid delete operation");
@@ -136,6 +145,7 @@ public abstract class PathRef implements Comparable<PathRef>  {
         }
 
     }
+
     private static class ArrayIndexPathRef extends PathRef {
 
         private int index;
@@ -151,6 +161,11 @@ public abstract class PathRef implements Comparable<PathRef>  {
             configuration.jsonProvider().setArrayIndex(parent, index, newVal);
         }
 
+        public void convert(ValueConverter valueConverter, Configuration configuration){
+            Object currentValue = configuration.jsonProvider().getArrayIndex(parent, index);
+            configuration.jsonProvider().setArrayIndex(parent, index, valueConverter.convert(currentValue));
+        }
+
         public void delete(Configuration configuration){
             configuration.jsonProvider().removeProperty(parent, value);
         }
@@ -209,6 +224,13 @@ public abstract class PathRef implements Comparable<PathRef>  {
             configuration.jsonProvider().setProperty(parent, property, newVal);
         }
 
+        @Override
+        public void convert(ValueConverter valueConverter, Configuration configuration) {
+            Object currentValue = configuration.jsonProvider().getMapValue(parent, property);
+            configuration.jsonProvider().setProperty(parent, property, valueConverter.convert(currentValue));
+        }
+
+
         public void delete(Configuration configuration){
             configuration.jsonProvider().removeProperty(parent, property);
         }
@@ -266,6 +288,12 @@ public abstract class PathRef implements Comparable<PathRef>  {
                 configuration.jsonProvider().setProperty(parent, property, newVal);
             }
         }
+        public void convert(ValueConverter valueConverter, Configuration configuration) {
+            for (String property : properties) {
+                Object currentValue = configuration.jsonProvider().getMapValue(parent, property);
+                configuration.jsonProvider().setProperty(parent, property, valueConverter.convert(currentValue));
+            }
+        }
 
         public void delete(Configuration configuration){
             for (String property : properties) {

json-path/src/main/java/com/jayway/jsonpath/internal/ValueConverter.java

@@ -0,0 +1,10 @@
+package com.jayway.jsonpath.internal;
+
+/**
+ * Created by tom on 29/04/15.
+ */
+public interface ValueConverter {
+
+    public Object convert(Object currentValue);
+
+}

json-path/src/test/java/com/jayway/jsonpath/WriteTest.java

@@ -1,5 +1,6 @@
 package com.jayway.jsonpath;
 
+import com.jayway.jsonpath.internal.ValueConverter;
 import org.junit.Test;
 
 import java.util.*;
@@ -259,4 +260,57 @@ public class WriteTest extends BaseTest {
     public void non_existent_key_rename_not_allowed(){
         Object o = parse(JSON_DOCUMENT).renameKey("$", "fake", "new-fake").json();
     }
+
+    @Test(expected = InvalidModificationException.class)
+    public void rootCannotBeConverted(){
+        ValueConverter valueConverter = new ValueConverter() {
+            @Override
+            public Object convert(Object currentValue) {
+                return currentValue.toString()+"converted";
+            }
+        };
+        Object o = parse(JSON_DOCUMENT).convert("$", valueConverter).json();
+    }
+
+    @Test
+    public void single_match_value_can_be_converted(){
+        ValueConverter valueConverter = new ToStringValueConverterImpl();
+        String stringResult = parse(JSON_DOCUMENT).convert("$.string-property", valueConverter).read("$.string-property");
+        assertThat(stringResult.endsWith("converted")).isTrue();
+    }
+
+    @Test
+    public void object_can_be_converted(){
+        ValueConverter valueConverter = new ToStringValueConverterImpl();
+        DocumentContext documentContext = parse(JSON_DOCUMENT);
+        Object list = documentContext.read("$..book");
+        assertThat(list).isInstanceOf(List.class);
+        String result = ((List<String>)documentContext.convert("$..book", valueConverter).read("$..book")).get(0);
+        assertThat(result).isInstanceOf(String.class);
+        assertThat(((String)result).endsWith("converted")).isTrue();
+    }
+
+    @Test
+    public void multi_match_path_can_be_converted(){
+        ValueConverter valueConverter = new ToStringValueConverterImpl();
+        List<Double> doubleResult = parse(JSON_DOCUMENT).read("$..display-price");
+        for(Double dRes : doubleResult){
+            assertThat(dRes).isInstanceOf(Double.class);
+        }
+        List<String> stringResult = parse(JSON_DOCUMENT).convert("$..display-price", valueConverter).read("$..display-price");
+        for(String sRes : stringResult){
+            assertThat(sRes).isInstanceOf(String.class);
+            assertThat(sRes.endsWith("converted")).isTrue();
+        }
+    }
+
+    // Helper converter implementation for test cases.
+    private class ToStringValueConverterImpl implements ValueConverter{
+
+        @Override
+        public Object convert(Object currentValue) {
+            return currentValue.toString()+"converted";
+        }
+    }
+
 }