Externalized the cache using CacheProvider spi.

Set the CacheProvider in the Configuration:
Configuration
            .builder()
            .mappingProvider(new <<Implementation of mapping provider>>)
            .jsonProvider(new <<Implementation of JsonProvider>>)
            .cacheProvider(new <<implementation of CacheProvider>>)
            .build();

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

@@ -15,6 +15,8 @@
 package com.jayway.jsonpath;
 
 import com.jayway.jsonpath.internal.DefaultsImpl;
+import com.jayway.jsonpath.spi.cache.CacheProvider;
+import com.jayway.jsonpath.spi.cache.DefaultCache;
 import com.jayway.jsonpath.spi.json.JsonProvider;
 import com.jayway.jsonpath.spi.mapper.MappingProvider;
 
@@ -55,14 +57,16 @@ public class Configuration {
     private final MappingProvider mappingProvider;
     private final Set<Option> options;
     private final Collection<EvaluationListener> evaluationListeners;
+    private final CacheProvider cacheProvider;
 
-    private Configuration(JsonProvider jsonProvider, MappingProvider mappingProvider, EnumSet<Option> options, Collection<EvaluationListener> evaluationListeners) {
+    private Configuration(JsonProvider jsonProvider, MappingProvider mappingProvider, CacheProvider cacheProvider, EnumSet<Option> options, Collection<EvaluationListener> evaluationListeners) {
         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");
         this.jsonProvider = jsonProvider;
         this.mappingProvider = mappingProvider;
+        this.cacheProvider = cacheProvider;
         this.options = Collections.unmodifiableSet(options);
         this.evaluationListeners = Collections.unmodifiableCollection(evaluationListeners);
     }
@@ -127,6 +131,23 @@ public class Configuration {
         return mappingProvider;
     }
     
+    /**
+     * Creates a new Configuration based on the given {@link com.jayway.jsonpath.spi.cache.CacheProvider}
+     * @param newCacheProvider cache provider to use in new configuration
+     * @return a new configuration
+     */
+    public Configuration CacheProvider(CacheProvider newCacheProvider) {
+        return Configuration.builder().jsonProvider(jsonProvider).mappingProvider(mappingProvider).cacheProvider(newCacheProvider).options(options).evaluationListener(evaluationListeners).build();
+    }
+
+    /**
+     * Returns {@link com.jayway.jsonpath.spi.cache.CacheProvider} used by this configuration
+     * @return cacheProvider used
+     */
+    public CacheProvider CacheProvider() {
+        return cacheProvider;
+    }
+
     /**
      * Creates a new configuration by adding the new options to the options used in this configuration.
      * @param options options to add
@@ -189,6 +210,7 @@ public class Configuration {
 
         private JsonProvider jsonProvider;
         private MappingProvider mappingProvider;
+        private CacheProvider cacheProvider = new DefaultCache(200);
         private EnumSet<Option> options = EnumSet.noneOf(Option.class);
         private Collection<EvaluationListener> evaluationListener = new ArrayList<EvaluationListener>();
 
@@ -202,6 +224,11 @@ public class Configuration {
             return this;
         }
         
+        public ConfigurationBuilder cacheProvider(CacheProvider provider) {
+            this.cacheProvider = provider;
+            return this;
+        }
+
         public ConfigurationBuilder options(Option... flags) {
             if(flags.length > 0) {
                 this.options.addAll(asList(flags));
@@ -233,8 +260,11 @@ public class Configuration {
                 if (mappingProvider == null){
                     mappingProvider = defaults.mappingProvider();
                 }
+                if (cacheProvider == null){
+                    cacheProvider = defaults.cacheProvider();
+                }
             }
-            return new Configuration(jsonProvider, mappingProvider, options, evaluationListener);
+            return new Configuration(jsonProvider, mappingProvider, cacheProvider, options, evaluationListener);
         }
     }
 
@@ -258,5 +288,12 @@ public class Configuration {
          */
         MappingProvider mappingProvider();
         
+        /**
+         * Returns the default {@link com.jayway.jsonpath.spi.cache.CacheProvider}
+         *
+         * @return default cache provider
+         */
+        CacheProvider cacheProvider();
+
     }
 }

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

@@ -5,6 +5,8 @@ import java.util.Set;
 
 import com.jayway.jsonpath.Configuration.Defaults;
 import com.jayway.jsonpath.Option;
+import com.jayway.jsonpath.spi.cache.DefaultCache;
+import com.jayway.jsonpath.spi.cache.CacheProvider;
 import com.jayway.jsonpath.spi.json.JsonProvider;
 import com.jayway.jsonpath.spi.json.JsonSmartJsonProvider;
 import com.jayway.jsonpath.spi.mapper.JsonSmartMappingProvider;
@@ -16,6 +18,8 @@ public final class DefaultsImpl implements Defaults {
 
   private final MappingProvider mappingProvider = new JsonSmartMappingProvider();
   
+  private final CacheProvider cacheProvider = new DefaultCache(200);
+
   @Override
   public JsonProvider jsonProvider() {
     return new JsonSmartJsonProvider();
@@ -32,6 +36,11 @@ public final class DefaultsImpl implements Defaults {
   }
 
   private DefaultsImpl() {
+  }
+
+	@Override
+	public CacheProvider cacheProvider() {
+		return cacheProvider;
 	};
 
 }

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

@@ -132,9 +132,15 @@ public class JsonReader implements ParseContext, DocumentContext {
     @Override
     public <T> T read(String path, Predicate... filters) {
         notEmpty(path, "path can not be null or empty");
+        JsonPath cached = configuration.CacheProvider().get(path);
+        if(cached != null){
+        	return read(cached);
+        }else {
         	return read(compile(path, filters));
         }
 
+    }
+
     @Override
     public <T> T read(String path, Class<T> type, Predicate... filters) {
         return convert(read(path, filters), type, configuration);

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

@@ -66,12 +66,12 @@ public class PathCompiler {
                 fail("Path must not end wid a scan operation '..'");
             }
             LinkedList filterStack = new LinkedList<Predicate>(asList(filters));
-            String cacheKey = Utils.concat(path, filterStack.toString());
-            Path p = cache.get(cacheKey);
-            if (p == null) {
-                p = new PathCompiler(path.trim(), filterStack).compile();
-                cache.put(cacheKey, p);
-            }
+//            String cacheKey = Utils.concat(path, filterStack.toString());
+//            Path p = cache.get(cacheKey);
+//            if (p == null) {
+            Path p = new PathCompiler(path.trim(), filterStack).compile();
+//                cache.put(cacheKey, p);
+//            }
             return p;
         } catch (Exception e) {
             InvalidPathException ipe;

json-path/src/main/java/com/jayway/jsonpath/spi/cache/CacheProvider.java

@@ -0,0 +1,23 @@
+package com.jayway.jsonpath.spi.cache;
+
+import com.jayway.jsonpath.InvalidJsonException;
+import com.jayway.jsonpath.JsonPath;
+
+public interface CacheProvider {
+
+	/**
+     * Get the Cached JsonPath
+     * @param key cache key to lookup the JsonPath
+     * @return JsonPath
+     */
+	public JsonPath get(String key);
+	
+	/**
+     * Add JsonPath to the cache
+     * @param key cache key to store the JsonPath
+     * @param value JsonPath to be cached
+     * @return void
+     * @throws InvalidJsonException
+     */
+	public void put(String key, JsonPath value);
+}

json-path/src/main/java/com/jayway/jsonpath/spi/cache/DefaultCache.java

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2011 the original author or authors.
+ * 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.
+ */
+package com.jayway.jsonpath.spi.cache;
+
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.ReentrantLock;
+
+import com.jayway.jsonpath.JsonPath;
+
+/*
+ * LRU implementation copied from com.jayway.jsonpath.internal.Cache
+ * Will have the same bugs
+ */
+
+public class DefaultCache implements CacheProvider{
+
+    private final ReentrantLock lock = new ReentrantLock();
+
+    private final Map<String, JsonPath> map = new ConcurrentHashMap<String, JsonPath>();
+    private final Deque<String> queue = new LinkedList<String>();
+    private final int limit;
+
+    public DefaultCache(int limit) {
+        this.limit = limit;
+    }
+
+    public void put(String key, JsonPath value) {
+        JsonPath oldValue = map.put(key, value);
+        if (oldValue != null) {
+            removeThenAddKey(key);
+        } else {
+            addKey(key);
+        }
+        if (map.size() > limit) {
+            map.remove(removeLast());
+        }
+    }
+
+    public JsonPath get(String key) {
+        if(map.containsKey(key)){
+            removeThenAddKey(key);
+        }
+        return map.get(key);
+    }
+
+    private void addKey(String key) {
+        lock.lock();
+        try {
+            queue.addFirst(key);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    private String removeLast() {
+        lock.lock();
+        try {
+            final String removedKey = queue.removeLast();
+            return removedKey;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    private void removeThenAddKey(String key) {
+        lock.lock();
+        try {
+            queue.removeFirstOccurrence(key);
+            queue.addFirst(key);
+        } finally {
+            lock.unlock();
+        }
+
+    }
+
+    private void removeFirstOccurrence(String key) {
+        lock.lock();
+        try {
+            queue.removeFirstOccurrence(key);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public JsonPath getSilent(String key) {
+        return map.get(key);
+    }
+
+    public void remove(String key) {
+        removeFirstOccurrence(key);
+        map.remove(key);
+    }
+
+    public int size() {
+        return map.size();
+    }
+
+    public String toString() {
+        return map.toString();
+    }
+}