Streaming extensions for JsonPath

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

@@ -0,0 +1,37 @@
+/*
+ * 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;
+
+import com.jayway.jsonpath.internal.Path;
+
+/**
+ * A listener that can be registered on a {@link com.jayway.jsonpath.internal.token.TokenStack} that is notified when a
+ * result is found for a specific registered path
+ */
+public interface EvaluationCallback {
+
+    /**
+     * Callback invoked when result is found
+     * @param path -- the specific path that was triggered
+     */
+    public void resultFound(Path path) throws Exception;
+
+    /**
+     * Callback invoked when the parser leaves the region in which the match
+     * was found
+     * @param path -- the specific path that was untriggered
+     */
+    public void resultFoundExit(Path path) throws Exception;
+}

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

@@ -15,6 +15,7 @@
 package com.jayway.jsonpath;
 
 import com.jayway.jsonpath.internal.Utils;
+import com.jayway.jsonpath.internal.token.TokenStack;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -28,7 +29,7 @@
 /**
  *
  */
-public abstract class Filter implements Predicate {
+public abstract class Filter implements StreamingPredicate {
 
     private static final Logger logger = LoggerFactory.getLogger(Filter.class);
     private static final Pattern OPERATOR_SPLIT = Pattern.compile("((?<=&&|\\|\\|)|(?=&&|\\|\\|))");
@@ -56,6 +57,8 @@ public static Filter filter(Collection<Predicate> predicates) {
     @Override
     public abstract boolean apply(PredicateContext ctx);
 
+    @Override
+    public abstract boolean check(TokenStack stack, int idx);
 
     public Filter or(final Predicate other){
         return new OrFilter(this, other);
@@ -80,6 +83,11 @@ public boolean apply(PredicateContext ctx) {
             return predicate.apply(ctx);
         }
 
+        @Override
+        public boolean check(TokenStack stack, int idx) {
+            return ((StreamingPredicate)predicate).check(stack, idx);
+        }
+
         @Override
         public String toString() {
             return predicate.toString();
@@ -114,6 +122,16 @@ public boolean apply(PredicateContext ctx) {
             return true;
         }
 
+        @Override
+        public boolean check(TokenStack stack, int idx) {
+            for (Predicate predicate : predicates) {
+                if(!((StreamingPredicate)predicate).check(stack, idx)){
+                    return false;
+                }
+            }
+            return true;
+        }
+
         @Override
         public String toString() {
             return "(" + Utils.join(" && ", predicates) + ")";
@@ -124,7 +142,7 @@ private static final class OrFilter extends Filter {
 
         private final Predicate left;
         private final Predicate right;
-  
+
         private OrFilter(Predicate left, Predicate right) {
             this.left = left;
             this.right = right;
@@ -140,6 +158,12 @@ public boolean apply(PredicateContext ctx) {
             return a || right.apply(ctx);
         }
 
+        @Override
+        public boolean check(TokenStack stack, int idx) {
+            boolean a = ((StreamingPredicate)left).check(stack, idx);
+            return a || ((StreamingPredicate)right).check(stack, idx);
+        }
+
         @Override
         public String toString() {
             return "(" + left.toString() + " || " + right.toString() + ")";

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

@@ -0,0 +1,25 @@
+/*
+ * 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;
+
+import com.jayway.jsonpath.internal.token.TokenStack;
+
+/**
+ *
+ */
+public interface StreamingPredicate extends Predicate {
+
+    boolean check(TokenStack stack, int idx);
+}

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

@@ -17,6 +17,7 @@
 import com.jayway.jsonpath.Configuration;
 import com.jayway.jsonpath.internal.token.EvaluationContextImpl;
 import com.jayway.jsonpath.internal.token.PathToken;
+import com.jayway.jsonpath.internal.token.TokenStack;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -61,6 +62,11 @@ public EvaluationContext evaluate(Object document, Object rootDocument, Configur
         return evaluate(document, rootDocument, configuration, false);
     }
 
+    @Override
+    public boolean checkForMatch(TokenStack stack) {
+        return root.checkForMatch(stack, 0);
+    }
+
     @Override
     public boolean isDefinite() {
         return root.isPathDefinite();

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

@@ -15,6 +15,7 @@
 package com.jayway.jsonpath.internal;
 
 import com.jayway.jsonpath.Configuration;
+import com.jayway.jsonpath.internal.token.TokenStack;
 
 /**
  *
@@ -43,6 +44,12 @@ public interface Path {
      */
     EvaluationContext evaluate(Object document, Object rootDocument, Configuration configuration, boolean forUpdate);
 
+    /**
+     * checks the parser state represented by stack and determines if this
+     * path matches it
+     */
+    boolean checkForMatch(TokenStack stack);
+
     /**
      *
      * @return true id this path is definite

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

@@ -178,6 +178,85 @@ public String getPathFragment() {
         return sb.toString();
     }
 
+    @Override
+    public boolean checkForMatch(TokenStack stack, int idx)
+    {
+        if (stack.getStack().size() <= idx) return false;
+        TokenStackElement curr = stack.getStack().get(idx);
+
+        if (curr.getType() == TokenType.ARRAY_TOKEN) {
+            ArrayToken token = (ArrayToken)curr;
+            int tokenIdx = token.getIndex();
+            switch (operation) {
+            case CONTEXT_SIZE:
+            {
+                if (isLeaf()) {
+                    return stack.getStack().size() - 1 == idx;
+                }
+                return next().checkForMatch(stack, idx + 1);
+            }
+            case SLICE_TO:
+            {
+                int to = criteria.get(0).intValue();
+                if (tokenIdx < to) {
+                    if (isLeaf()) {
+                        return stack.getStack().size() - 1 == idx;
+                    }
+                    return next().checkForMatch(stack, idx + 1);
+                }
+                break;
+            }
+            case SLICE_FROM:
+            {
+                int from = criteria.get(0).intValue();
+                if (from <= tokenIdx) {
+                    if (isLeaf()) {
+                        return stack.getStack().size() - 1 == idx;
+                    }
+                    return next().checkForMatch(stack, idx + 1);
+                }
+                break;
+            }
+            case SLICE_BETWEEN:
+            {
+                int from = criteria.get(0).intValue();
+                int to = criteria.get(1).intValue();
+                if (from <= tokenIdx && tokenIdx < to) {
+                    if (isLeaf()) {
+                        return stack.getStack().size() - 1 == idx;
+                    }
+                    return next().checkForMatch(stack, idx + 1);
+                }
+                break;
+            }
+            case INDEX_SEQUENCE:
+            {
+                for (Integer i : criteria) {
+                    if (i.intValue() == tokenIdx) {
+                        if (isLeaf()) {
+                            return stack.getStack().size() - 1 == idx;
+                        }
+                        return next().checkForMatch(stack, idx + 1);
+                    }
+                }
+                break;
+            }
+            case SINGLE_INDEX:
+            {
+                if (criteria.get(0).intValue() == tokenIdx) {
+                    if (isLeaf()) {
+                        return stack.getStack().size() - 1 == idx;
+                    }
+                    return next().checkForMatch(stack, idx + 1);
+                }
+                break;
+            }
+            }
+        }
+
+        return false;
+    }
+
     @Override
     boolean isTokenDefinite() {
         return isDefinite;

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

@@ -0,0 +1,48 @@
+
+package com.jayway.jsonpath.internal.token;
+
+/**
+ *
+ * @author Hunter Payne
+ **/
+public class ArrayToken implements TokenStackElement
+{
+    int currentIndex;
+    TokenStackElement value; // can be an object, array, or property
+
+    public ArrayToken()
+    {
+        currentIndex = 0;
+        value = null;
+    }
+
+    public TokenType getType()
+    {
+        return TokenType.ARRAY_TOKEN;
+    }
+
+    public int getIndex()
+    {
+        return currentIndex;
+    }
+
+    public TokenStackElement getValue()
+    {
+        return value;
+    }
+
+    public void setValue(TokenStackElement elem)
+    {
+        if (value != null) {
+            ++currentIndex;
+        }
+        value = elem;
+    }
+
+    public String toString()
+    {
+        return "Array[idx=" + currentIndex + "]";
+    }
+}
+
+// End ArrayToken.java

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

@@ -0,0 +1,33 @@
+
+package com.jayway.jsonpath.internal.token;
+
+/**
+ *
+ * @author Hunter Payne
+ **/
+public class FloatToken implements TokenStackElement
+{
+    public float value;
+
+    public FloatToken(float f)
+    {
+        value = f;
+    }
+
+    public TokenType getType()
+    {
+        return TokenType.FLOAT_TOKEN;
+    }
+
+    public TokenStackElement getValue()
+    {
+        return null;
+    }
+
+    public void setValue(TokenStackElement elem)
+    {
+        throw new RuntimeException();
+    }
+}
+
+// End FloatToken.java

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

@@ -0,0 +1,33 @@
+
+package com.jayway.jsonpath.internal.token;
+
+/**
+ *
+ * @author Hunter Payne
+ **/
+public class IntToken implements TokenStackElement
+{
+    public int value;
+
+    public IntToken(int f)
+    {
+        value = f;
+    }
+
+    public TokenType getType()
+    {
+        return TokenType.INTEGER_TOKEN;
+    }
+
+    public TokenStackElement getValue()
+    {
+        return null;
+    }
+
+    public void setValue(TokenStackElement elem)
+    {
+        throw new RuntimeException();
+    }
+}
+
+// End IntToken.java