JsonRootEatingInputStreamFilter.java

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package com.sun.jersey.json.impl;

import java.io.IOException;
import java.io.InputStream;
import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.JsonToken;

/**
 *
 * @author Jakub.Podlesak@Sun.COM
 */
public class JsonRootEatingInputStreamFilter extends FilteringInputStream {

    private JsonParser jsonParser;
    private JsonGenerator jsonGenerator;
    private int depth;
    private BufferingInputOutputStream buffers;

    public JsonRootEatingInputStreamFilter(InputStream inputStream) throws IOException {
        JsonFactory jsonFactory = new JsonFactory();
        this.jsonParser = jsonFactory.createJsonParser(inputStream);
        this.buffers = new BufferingInputOutputStream();
        this.jsonGenerator = jsonFactory.createJsonGenerator(this.buffers, JsonEncoding.UTF8);
        this.depth = 0;
    }

    protected byte[] nextBytes() throws IOException {
        if (!jsonParser.hasCurrentToken()) {
            jsonParser.nextToken();
        }

        final JsonToken token = jsonParser.getCurrentToken();

        if ((depth == 0) && (token == JsonToken.START_OBJECT)) {
            jsonParser.nextToken();
            return nextBytes();
        }

        if ((depth == 0) && (token == JsonToken.FIELD_NAME)) {
            depth++;
            jsonParser.nextToken();
            return nextBytes();
        }

        if ((depth == 1) && ((token == JsonToken.END_OBJECT) || (token == JsonToken.END_ARRAY))) {
            jsonParser.nextToken();
            return null;
        }

        jsonGenerator.copyCurrentEvent(jsonParser);
        jsonGenerator.flush();
        jsonParser.nextToken();

        if ((token == JsonToken.START_ARRAY) || (token == JsonToken.START_OBJECT)) {
            depth++;
        } else if ((token == JsonToken.END_ARRAY) || (token == JsonToken.END_OBJECT)) {
            depth--;
        }

        return buffers.nextBytes();
    }

    @Override
    public int available() throws IOException {
        return super.available()/* + buffers.available()*/;
    }


}