com.hazelcast.org.jsfr.json.SurfingContext Maven / Gradle / Ivy
/*
* MIT License
*
* Copyright (c) 2019 WANG Lingsong
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.hazelcast.org.jsfr.json;
import com.hazelcast.org.jsfr.json.SurfingConfiguration.Binding;
import com.hazelcast.org.jsfr.json.SurfingConfiguration.IndefinitePathBinding;
import com.hazelcast.org.jsfr.json.filter.CloneableJsonPathFilter;
import com.hazelcast.org.jsfr.json.filter.JsonPathFilter;
import com.hazelcast.org.jsfr.json.path.ArrayIndex;
import com.hazelcast.org.jsfr.json.path.ChildNode;
import com.hazelcast.org.jsfr.json.path.PathOperator;
import com.hazelcast.org.jsfr.json.path.PathOperator.Type;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.function.Function;
/**
* Receives JSON reading events from input data JSON parser, matches and delegates those events to filters
* verifier (if there are filters registered in JSON path) and to content dispatcher that does value collection.
*
* SurfingContext is not thread-safe.
*/
public class SurfingContext implements ParsingContext, JsonSaxHandler {
private boolean stopped;
private boolean paused;
private JsonPosition currentPosition;
private Map transientMap;
private final ContentDispatcher dispatcher = new ContentDispatcher();
private final FilterVerifierDispatcher filterVerifierDispatcher;
private final SurfingConfiguration config;
SurfingContext(SurfingConfiguration config) {
this.config = config;
if (config.hasFilter()) {
this.filterVerifierDispatcher = new FilterVerifierDispatcher();
this.dispatcher.addReceiver(this.filterVerifierDispatcher);
} else {
this.filterVerifierDispatcher = null;
}
}
private void doMatching(PrimitiveHolder primitiveHolder) {
LinkedList listeners = null;
int currentDepth = currentPosition.pathDepth();
if (config.hasFilter()) {
// skip matching if "skipOverlappedPath" is enabled
if (config.isSkipOverlappedPath() && dispatcher.size() > 1) {
return;
}
for (IndefinitePathBinding binding : config.getIndefinitePathLookup()) {
if (binding.minimumPathDepth <= currentDepth) {
listeners = doMatchingWithFilter(binding, primitiveHolder, listeners, false);
} else {
break;
}
}
Binding[] bindings = config.getDefinitePathBind(currentDepth);
if (bindings != null) {
for (Binding binding : bindings) {
listeners = doMatchingWithFilter(binding, primitiveHolder, listeners, true);
}
}
} else {
// skip matching if "skipOverlappedPath" is enabled
if (config.isSkipOverlappedPath() && !dispatcher.isEmpty()) {
return;
}
for (IndefinitePathBinding binding : config.getIndefinitePathLookup()) {
if (binding.minimumPathDepth <= currentDepth) {
listeners = doMatching(binding, primitiveHolder, listeners, false);
} else {
break;
}
}
Binding[] bindings = config.getDefinitePathBind(currentDepth);
if (bindings != null) {
for (Binding binding : bindings) {
listeners = doMatching(binding, primitiveHolder, listeners, true);
}
}
}
if (listeners != null) {
JsonCollector collector = new JsonCollector(listeners, this, config);
dispatcher.addReceiver(collector);
}
}
private LinkedList doMatchingWithFilter(Binding binding, PrimitiveHolder primitiveHolder,
LinkedList listeners, boolean definiteBinding) {
boolean matched = definiteBinding
? binding.jsonPath.match(currentPosition) : binding.jsonPath.matchWithDeepScan(currentPosition);
if (matched) {
if (binding.filter != null) {
// JsonPathFilter is stateful so clone is required
// TODO not clone for stateless filter
this.filterVerifierDispatcher.addVerifier(binding, new JsonFilterVerifier(currentPosition, config,
(JsonPathFilter) ((CloneableJsonPathFilter) binding.filter).cloneMe(),
this.filterVerifierDispatcher.getVerifier(binding.dependency)));
} else {
if (primitiveHolder != null) {
dispatchPrimitiveWithFilter(binding.getListeners(), primitiveHolder.getValue(), binding.dependency);
} else {
JsonFilterVerifier verifier = this.filterVerifierDispatcher.getVerifier(binding.dependency);
return mergeCollections(listeners, binding.listeners,
verifier != null ? verifier::addListener : Function.identity());
}
}
}
return listeners;
}
/**
* Adds elements from `srcColl` into `targetColl`, transforming them using
* the `srcMapping`. If `targetColl` is null, creates a new collection.
*/
private static LinkedList mergeCollections(LinkedList targetColl, T[] srcColl, Function srcMapping) {
if (targetColl == null) {
targetColl = new LinkedList<>();
}
for (T element : srcColl) {
targetColl.add(srcMapping.apply(element));
}
return targetColl;
}
private LinkedList doMatching(Binding binding, PrimitiveHolder primitiveHolder,
LinkedList listeners, boolean definiteBinding) {
boolean matched = definiteBinding ? binding.jsonPath.match(currentPosition)
: binding.jsonPath.matchWithDeepScan(currentPosition);
if (matched) {
if (primitiveHolder != null) {
dispatchPrimitive(binding.getListeners(), primitiveHolder.getValue());
} else {
return mergeCollections(listeners, binding.listeners, Function.identity());
}
}
return listeners;
}
private void dispatchPrimitiveWithFilter(JsonPathListener[] listeners, Object primitive, Binding dependency) {
if (dependency != null) {
JsonFilterVerifier filterVerifier = this.filterVerifierDispatcher.getVerifier(dependency);
for (JsonPathListener listener : listeners) {
JsonPathListener newListener = filterVerifier.addListener(listener);
newListener.onValue(primitive, this);
}
} else {
dispatchPrimitive(listeners, primitive);
}
}
private void dispatchPrimitive(JsonPathListener[] listeners, Object primitive) {
DispatchUtil.dispatchValueToListeners(primitive, listeners, this, config.getErrorHandlingStrategy());
}
@Override
public boolean startJSON() {
currentPosition = JsonPosition.start();
doMatching(null);
dispatcher.startJSON();
return true;
}
@Override
public boolean endJSON() {
dispatcher.endJSON();
// clear resources
currentPosition.clear();
currentPosition = null;
this.stop();
return true;
}
@Override
public boolean startObject() {
if (shouldBreak()) {
return false;
}
PathOperator currentNode = currentPosition.peek();
switch (currentNode.getType()) {
case OBJECT:
doMatching(null);
break;
case ARRAY:
accumulateArrayIndex(currentNode);
// startArrayElement();
doMatching(null);
break;
case ROOT:
break;
default:
throw new IllegalStateException();
}
currentPosition.stepIntoObject();
dispatcher.startObject();
return true;
}
@Override
public boolean endObject() {
if (shouldBreak()) {
return false;
}
currentPosition.stepOutObject();
dispatcher.endObject();
return true;
}
@Override
public boolean startObjectEntry(String key) {
if (shouldBreak()) {
return false;
}
currentPosition.updateObjectEntry(key);
dispatcher.startObjectEntry(key);
return true;
}
@Override
public boolean startArray() {
if (shouldBreak()) {
return false;
}
PathOperator currentNode = currentPosition.peek();
switch (currentNode.getType()) {
case OBJECT:
//doMatching(null);
break;
case ARRAY:
accumulateArrayIndex(currentNode);
// startArrayElement();
doMatching(null);
break;
case ROOT:
break;
default:
throw new IllegalStateException();
}
currentPosition.stepIntoArray();
dispatcher.startArray();
return true;
}
private void accumulateArrayIndex(PathOperator arrayIndex) {
if (arrayIndex instanceof ArrayIndex) {
((ArrayIndex) arrayIndex).increaseArrayIndex();
} else {
throw new IllegalStateException("Only array and root array operators are expected");
}
}
@Override
public boolean endArray() {
if (shouldBreak()) {
return false;
}
currentPosition.stepOutArray();
dispatcher.endArray();
return true;
}
@Override
public boolean primitive(PrimitiveHolder primitiveHolder) {
if (shouldBreak()) {
return false;
}
PathOperator currentNode = currentPosition.peek();
switch (currentNode.getType()) {
case OBJECT:
doMatching(primitiveHolder);
break;
case ARRAY:
accumulateArrayIndex(currentNode);
// startArrayElement();
doMatching(primitiveHolder);
break;
case ROOT:
break;
default:
throw new IllegalStateException();
}
dispatcher.primitive(primitiveHolder);
return true;
}
@Override
public String getJsonPath() {
return this.currentPosition.toString();
}
@Override
public String getCurrentFieldName() {
PathOperator top = this.currentPosition.peek();
if (top instanceof ChildNode) {
return ((ChildNode) top).getKey();
} else {
return null;
}
}
@Override
public int getCurrentArrayIndex() {
PathOperator top = this.currentPosition.peek();
if (top.getType() == Type.ARRAY) {
return ((ArrayIndex) top).getArrayIndex();
} else {
return -1;
}
}
@Override
public void save(String key, Object value) {
if (this.transientMap == null) {
this.transientMap = new HashMap<>();
}
this.transientMap.put(key, value);
}
@Override
public T load(String key, Class tClass) {
return this.transientMap != null ? tClass.cast(this.transientMap.get(key)) : null;
}
@Override
public T cast(Object object, Class tClass) {
//noinspection unchecked
return (T) this.config.getJsonProvider().cast(object, tClass);
}
public boolean shouldBreak() {
return this.stopped || this.paused;
}
@Override
public void stop() {
this.stopped = true;
this.paused = false;
}
@Override
public boolean isStopped() {
return this.stopped;
}
@Override
public void pause() {
this.paused = true;
}
@Override
public void resume() {
this.paused = false;
}
@Override
public boolean isPaused() {
return this.paused;
}
public SurfingConfiguration getConfig() {
return config;
}
}
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