Added result cache for root ($) queries performed by predicates.

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

@@ -208,8 +208,9 @@ public class Criteria implements Predicate {
         MATCHES {
             @Override
             boolean eval(Object expected, final Object actual, final PredicateContext ctx) {
+                PredicateContextImpl pci = (PredicateContextImpl) ctx;
                 Predicate exp = (Predicate) expected;
-                return exp.apply(new PredicateContextImpl(actual, ctx.root(), ctx.configuration()));
+                return exp.apply(new PredicateContextImpl(actual, ctx.root(), ctx.configuration(), pci.documentPathCache()));
             }
         },
         NOT_EMPTY {
@@ -286,7 +287,7 @@ public class Criteria implements Predicate {
         if (CriteriaType.EXISTS == criteriaType) {
             boolean exists = ((Boolean) expected);
             try {
-                Configuration c = Configuration.builder().jsonProvider(ctx.configuration().jsonProvider()).options().build();
+                Configuration c = Configuration.builder().jsonProvider(ctx.configuration().jsonProvider()).options(Option.REQUIRE_PROPERTIES).build();
                 path.evaluate(ctx.item(), ctx.root(), c).getValue();
                 return exists;
             } catch (PathNotFoundException e) {
@@ -299,9 +300,16 @@ public class Criteria implements Predicate {
                 Object expectedVal = expected;
                 if(expected instanceof Path){
                     Path expectedPath = (Path) expected;
+
+                    if(ctx instanceof PredicateContextImpl){
+                        //This will use cache for document ($) queries
+                        PredicateContextImpl ctxi = (PredicateContextImpl) ctx;
+                        expectedVal = ctxi.evaluate(expectedPath);
+                    } else {
                         Object doc = expectedPath.isRootPath()?ctx.root():ctx.item();
                         expectedVal = expectedPath.evaluate(doc, ctx.root(), ctx.configuration()).getValue();
                     }
+                }
 
                 return criteriaType.eval(expectedVal, actual, ctx);
             } catch (ValueCompareException e) {

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

@@ -22,7 +22,9 @@ import com.jayway.jsonpath.internal.Path;
 import com.jayway.jsonpath.spi.json.JsonProvider;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 
 import static com.jayway.jsonpath.internal.Utils.notNull;
@@ -37,8 +39,10 @@ public class EvaluationContextImpl implements EvaluationContext {
     private final Object pathResult;
     private final Path path;
     private final Object rootDocument;
+    private final HashMap<Path, Object> documentEvalCache = new HashMap<Path, Object>();
     private int resultIndex = 0;
 
+
     public EvaluationContextImpl(Path path, Object rootDocument, Configuration configuration) {
         notNull(path, "path can not be null");
         notNull(rootDocument, "root can not be null");
@@ -50,6 +54,10 @@ public class EvaluationContextImpl implements EvaluationContext {
         this.pathResult = configuration.jsonProvider().createArray();
     }
 
+    public HashMap<Path, Object> documentEvalCache() {
+        return documentEvalCache;
+    }
+
     public void addResult(String path, Object model) {
         configuration.jsonProvider().setProperty(valueResult, resultIndex, model);
         configuration.jsonProvider().setProperty(pathResult, resultIndex, path);

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

@@ -16,17 +16,47 @@ package com.jayway.jsonpath.internal.token;
 
 import com.jayway.jsonpath.Configuration;
 import com.jayway.jsonpath.Predicate;
+import com.jayway.jsonpath.internal.Path;
 import com.jayway.jsonpath.spi.mapper.MappingException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
 
 public class PredicateContextImpl implements Predicate.PredicateContext {
+
+    private static final Logger logger = LoggerFactory.getLogger(PredicateContextImpl.class);
+
     private final Object contextDocument;
     private final Object rootDocument;
     private final Configuration configuration;
+    private final HashMap<Path, Object> documentPathCache;
 
-    public PredicateContextImpl(Object contextDocument, Object rootDocument, Configuration configuration) {
+    public PredicateContextImpl(Object contextDocument, Object rootDocument, Configuration configuration, HashMap<Path, Object> documentPathCache) {
         this.contextDocument = contextDocument;
         this.rootDocument = rootDocument;
         this.configuration = configuration;
+        this.documentPathCache = documentPathCache;
+    }
+
+    public Object evaluate(Path path){
+        Object result;
+        if(path.isRootPath()){
+            if(documentPathCache.containsKey(path)){
+                logger.debug("Using cached result for root path: " + path.toString());
+                result = documentPathCache.get(path);
+            } else {
+                result = path.evaluate(rootDocument, rootDocument, configuration).getValue();
+                documentPathCache.put(path, result);
+            }
+        } else {
+            result = path.evaluate(contextDocument, rootDocument, configuration).getValue();
+        }
+        return result;
+    }
+
+    public HashMap<Path, Object> documentPathCache() {
+        return documentPathCache;
     }
 
     @Override

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

@@ -49,7 +49,7 @@ public class PredicatePathToken extends PathToken {
     @Override
     public void evaluate(String currentPath, Object model, EvaluationContextImpl ctx) {
         if (ctx.jsonProvider().isMap(model)) {
-            if (accept(model, ctx.rootDocument(), ctx.configuration())) {
+            if (accept(model, ctx.rootDocument(), ctx.configuration(), ctx)) {
                 if (isLeaf()) {
                     ctx.addResult(currentPath, model);
                 } else {
@@ -61,7 +61,7 @@ public class PredicatePathToken extends PathToken {
             Iterable<?> objects = ctx.jsonProvider().toIterable(model);
 
             for (Object idxModel : objects) {
-                if (accept(idxModel, ctx.rootDocument(),  ctx.configuration())) {
+                if (accept(idxModel, ctx.rootDocument(),  ctx.configuration(), ctx)) {
                     handleArrayIndex(idx, currentPath, model, ctx);
                 }
                 idx++;
@@ -71,8 +71,8 @@ public class PredicatePathToken extends PathToken {
         }
     }
 
-    public boolean accept(final Object obj, final Object root, final Configuration configuration) {
-        Predicate.PredicateContext ctx = new PredicateContextImpl(obj, root, configuration);
+    public boolean accept(final Object obj, final Object root, final Configuration configuration, EvaluationContextImpl evaluationContext) {
+        Predicate.PredicateContext ctx = new PredicateContextImpl(obj, root, configuration, evaluationContext.documentEvalCache());
 
         for (Predicate predicate : predicates) {
             if (!predicate.apply (ctx)) {

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

@@ -161,7 +161,7 @@ public class ScanPathToken extends PathToken {
 
       @Override
       public boolean matches(Object model) {
-          return predicatePathToken.accept(model, ctx.rootDocument(), ctx.configuration());
+          return predicatePathToken.accept(model, ctx.rootDocument(), ctx.configuration(), ctx);
       }
     }
 

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

@@ -1,9 +1,13 @@
 package com.jayway.jsonpath;
 
+import com.jayway.jsonpath.internal.Path;
 import com.jayway.jsonpath.internal.spi.json.GsonJsonProvider;
 import com.jayway.jsonpath.internal.spi.mapper.GsonMappingProvider;
+import com.jayway.jsonpath.internal.token.EvaluationContextImpl;
 import com.jayway.jsonpath.internal.token.PredicateContextImpl;
 
+import java.util.HashMap;
+
 public class BaseTest {
     /*
     static {
@@ -84,6 +88,7 @@ public class BaseTest {
             "}";
 
     public Predicate.PredicateContext createPredicateContext(final Object check) {
-        return new PredicateContextImpl(check, check, Configuration.defaultConfiguration());
+
+        return new PredicateContextImpl(check, check, Configuration.defaultConfiguration(), new HashMap<Path, Object>());
     }
 }

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

@@ -37,4 +37,13 @@ public class InlineFilterTest extends BaseTest {
         assertThat(none2.size()).isEqualTo(0);
 
     }
+
+    @Test
+    public void document_queries_are_cached() {
+
+        Object read = reader.read("$.store.book[?(@.display-price <= $.max-price)]");
+
+        System.out.println(read);
+
+    }
 }