I'm trying to implement JSON array iterator with Jackson SAX parser (please, don't ask why). My app should work with huge files (up to 5 MiB), and that's a problem.
That's how I initialize JsonParser and call iterator creation. I create InputStream initialized with JSON placed in \raw folder.
private JsonArrayIterator getIterator(String needle) throws IOException
{
InputStream inputStream = getApplicationContext().getResources().openRawResource(R.raw.products);
inputStream.mark(-1);
try {
JsonParser jsonParser = createJsonParser(inputStream);
// Some unrelated code
return new JsonArrayIterator(jsonParser);
} catch (IOException e) {
e.printStackTrace();
} finally {
inputStream.close();
}
return null;
}
And here is my iterator class.
private Object parseNextObject() throws IOException {
// I'm not using ObjectMapper because of reasons
HashMap nextObject = new HashMap();
int objectsCount = 1;
while (objectsCount > 0) {
JsonToken currentToken = currentParser.nextValue();
if(currentToken == JsonToken.START_OBJECT) {
++objectsCount;
}
else if(currentToken == JsonToken.END_OBJECT) {
--objectsCount;
}
else if(currentToken == JsonToken.START_ARRAY) {
String currentName = currentParser.getCurrentName();
ArrayList list = new ArrayList(100);
JsonArrayIterator it = new JsonArrayIterator(currentParser);
while (it.hasNext()) {
list.add(it.next());
}
nextObject.put(currentName, list);
}
else {
// Here exception is throwed
nextObject.put(currentParser.getCurrentName(), currentParser.getText());
}
}
currentParser.nextToken(); // Skip END_OBJECT
return nextObject;
}
It seem to work perfe... OH, WAIT.
I have 3 sections (named arrays) in some huge file. It successfully parses first (a tiny one, under 1000 bytes). But I can't parse next.
Next array has nested array with simple objects (like this):
{
"properties":[
{
"id":"1",
"title":"\u0426\u0432\u0435\u0442",
"values":[
{
"id":"1_2",
"title":"\u0427\u0435\u0440\u043d\u044b\u0439"
},
{
"id":"1_5005",
"title":"\u0417\u0435\u043b\u0435\u043d\u044b\u0439"
},
{
"id":"1_5006",
"title":"\u0421\u0435\u0440\u044b\u0439"
}
]
}
]
}
For one object in values I call nextObject.put. currentParser.getCurrentName() is runs successfully and returns correct string, but currentParser.getText() fails. It's not a JSON problem: it perfectly being mapped on iOS. It's not an object or iterator creation problem: I can delete that where parser throws exception, but it will fail in the same place.
Here is stack trace:
05-15 21:57:28.617: ERROR/AndroidRuntime(14758): FATAL EXCEPTION: main
java.lang.NullPointerException: asset
at android.content.res.AssetManager.readAsset(Native Method)
at android.content.res.AssetManager.access$700(AssetManager.java:36)
at android.content.res.AssetManager$AssetInputStream.read(AssetManager.java:576)
at com.fasterxml.jackson.core.json.UTF8StreamJsonParser.loadMore(UTF8StreamJsonParser.java:174)
at com.fasterxml.jackson.core.base.ParserBase.loadMoreGuaranteed(ParserBase.java:425)
at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._finishString2(UTF8StreamJsonParser.java:1930)
at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._finishString(UTF8StreamJsonParser.java:1911)
at com.fasterxml.jackson.core.json.UTF8StreamJsonParser.getText(UTF8StreamJsonParser.java:276)
at ru.studiomobile.JsonArrayIterator.parseNextObject(JsonArrayIterator.java:57)
at ru.studiomobile.JsonArrayIterator.next(JsonArrayIterator.java:73)
at ru.studiomobile.JsonArrayIterator.parseNextObject(JsonArrayIterator.java:47)
at ru.studiomobile.JsonArrayIterator.next(JsonArrayIterator.java:73)
at ru.studiomobile.MainActivity$2.onClick(MainActivity.java:81)
at android.view.View.performClick(View.java:3127)
at android.view.View$PerformClick.run(View.java:12025)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4126)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)
I noticed that there are something called Utf8StreamJsonParser. It has a field named _inputEnd equal 4000 (why 4000?). When other field, _inputPtr, become bigger it throw an exception. How do I can handle it? I tried to use BufferedInputStream with predefined block size instead of InputStream but it had no effect.
Update
Info about some lines
47: list.add(it.next());
73: return parseNextObject();
75: e.printStackTrace();
Nothing special.
