JacksonArrayWrapperGenerator.java

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 * Copyright (c) 2010 Oracle and/or its affiliates. All rights reserved.
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 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
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 * file and include the License file at packager/legal/LICENSE.txt.
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package com.sun.jersey.json.impl.writer;

import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;
import org.codehaus.jackson.Base64Variant;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.JsonStreamContext;
import org.codehaus.jackson.JsonToken;
import org.codehaus.jackson.ObjectCodec;

/**
 *
 * @author japod
 */
public class JacksonArrayWrapperGenerator extends JsonGenerator {

   private enum State { START, AFTER_NULL, IN_THE_MIDDLE };

   State state = State.START;
   int depth = 0;
   final JsonGenerator generator;
   private boolean isClosed = false;
   final int arrayDepth;


   private JacksonArrayWrapperGenerator() {
       this(null, 0);
   }

    private JacksonArrayWrapperGenerator(JsonGenerator generator) {
        this(generator, 0);
    }

    private JacksonArrayWrapperGenerator(final JsonGenerator generator, final int arrayDepth) {
        this.generator = generator;
        this.arrayDepth = arrayDepth;
    }

    public static JsonGenerator createArrayWrapperGenerator(JsonGenerator g) {
        return new JacksonArrayWrapperGenerator(g);
    }

    public static JsonGenerator createArrayWrapperGenerator(final JsonGenerator g, final int arrayDepth) {
        return new JacksonArrayWrapperGenerator(g, arrayDepth);
    }

    private void aboutToWriteANonNull() throws IOException {
        if (depth == arrayDepth) {
            if (state == State.START) {
                generator.writeStartArray();
                state = State.IN_THE_MIDDLE;
            } else if (state == State.AFTER_NULL) {
                generator.writeStartArray();
                generator.writeNull();
                state = State.IN_THE_MIDDLE;
            }
        }
    }

    @Override @Deprecated
    public void enableFeature(Feature feature) {
        generator.enableFeature(feature);
    }

    @Override
    public JsonGenerator enable(Feature feature) {
        return generator.enable(feature);
    }

    @Override @Deprecated
    public void disableFeature(Feature feature) {
        generator.disableFeature(feature);
    }

    @Override
    public JsonGenerator disable(Feature feature) {
        return generator.disable(feature);
    }

    @Override
    public void setFeature(Feature feature, boolean enabled) {
        generator.setFeature(feature, enabled);
    }

    @Override @Deprecated
    public boolean isFeatureEnabled(Feature feature) {
        return generator.isFeatureEnabled(feature);
    }

    @Override
    public boolean isEnabled(Feature f) {
        return generator.isEnabled(f);
    }

    @Override
    public JsonGenerator useDefaultPrettyPrinter() {
        return generator.useDefaultPrettyPrinter();
    }

    @Override
    public JsonGenerator setCodec(ObjectCodec codec) {
        return generator.setCodec(codec);
    }

    @Override
    public ObjectCodec getCodec() {
        return generator.getCodec();
    }

    @Override
    public void writeRawValue(String rawString) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRawValue(rawString);
    }

    @Override
    public void writeRawValue(String rawString, int startIndex, int length) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRawValue(rawString, startIndex, length);
    }

    @Override
    public void writeRawValue(char[] rawChars, int startIndex, int length) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRaw(rawChars, startIndex, length);
    }

    @Override
    public void writeNumber(BigInteger number) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeNumber(number);

    }

    @Override
    public void writeObject(Object o) throws IOException, JsonProcessingException {
        aboutToWriteANonNull();
        generator.writeObject(o);
    }

    @Override
    public void writeTree(JsonNode node) throws IOException, JsonProcessingException {
        aboutToWriteANonNull();
        generator.writeTree(node);
    }

    @Override
    public boolean isClosed() {
        return isClosed;
    }

    @Override
    public JsonStreamContext getOutputContext() {
        return generator.getOutputContext();
    }

    @Override
    public void writeStartArray() throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeStartArray();
    }

    @Override
    public void writeEndArray() throws IOException, JsonGenerationException {
        generator.writeEndArray();
    }

    @Override
    public void writeStartObject() throws IOException, JsonGenerationException {
        if (arrayDepth > 0 && depth == arrayDepth) {
            generator.writeStartArray();
            generator.writeStartObject();
        } else {
            aboutToWriteANonNull();
            generator.writeStartObject();
        }
        depth++;
    }

    @Override
    public void writeEndObject() throws IOException, JsonGenerationException {
        if (arrayDepth > 0 && depth == arrayDepth) {
            generator.writeEndObject();
            generator.writeEndArray();
        } else {
            generator.writeEndObject();
        }
        depth--;
    }

    @Override
    public void writeFieldName(String name) throws IOException, JsonGenerationException {
        generator.writeFieldName(name);
    }

    @Override
    public void writeString(String s) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeString(s);
    }

    @Override
    public void writeString(char[] text, int start, int length) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeString(text, start, length);
    }

    @Override
    public void writeRaw(String raw) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRaw(raw);
    }

    @Override
    public void writeRaw(String raw, int start, int length) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRaw(raw, start, length);
    }

    @Override
    public void writeRaw(char[] raw, int start, int count) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRaw(raw, start, count);
    }

    @Override
    public void writeRaw(char c) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeRaw(c);
    }

    @Override
    public void writeBinary(Base64Variant variant, byte[] bytes, int start, int count) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeBinary(variant, bytes, start, count);
    }

    @Override
    public void writeNumber(int i) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeNumber(i);
    }

    @Override
    public void writeNumber(long l) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeNumber(l);
    }

    @Override
    public void writeNumber(double d) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeNumber(d);
    }

    @Override
    public void writeNumber(float f) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeNumber(f);
    }

    @Override
    public void writeNumber(BigDecimal bd) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeNumber(bd);
    }

    @Override
    public void writeNumber(String number) throws IOException, JsonGenerationException, UnsupportedOperationException {
        aboutToWriteANonNull();
        generator.writeNumber(number);
    }

    @Override
    public void writeBoolean(boolean b) throws IOException, JsonGenerationException {
        aboutToWriteANonNull();
        generator.writeBoolean(b);
    }

    @Override
    public void writeNull() throws IOException, JsonGenerationException {
        switch (state) {
            case START :
                state = State.AFTER_NULL;
                break;
            case AFTER_NULL :
                generator.writeStartArray();
                generator.writeNull();
                state = State.IN_THE_MIDDLE;
            default:
                generator.writeNull();
        }
    }

    @Override
    public void copyCurrentEvent(JsonParser parser) throws IOException, JsonProcessingException {
        if (JsonToken.VALUE_NULL != parser.getCurrentToken()) {
            aboutToWriteANonNull();
            generator.copyCurrentEvent(parser);
        } else {
            writeNull();
        }
    }

    @Override
    public void copyCurrentStructure(JsonParser parser) throws IOException, JsonProcessingException {
        generator.copyCurrentStructure(parser);
    }

    @Override
    public void flush() throws IOException {
        if (depth == arrayDepth) {
            switch (state) {
                case IN_THE_MIDDLE:
                    generator.writeEndArray();
                    break;
                case AFTER_NULL:
                case START:
                    generator.writeStartArray();
                    generator.writeEndArray();
                    break;
            }
        }
        generator.flush();
    }

    @Override
    public void close() throws IOException {
        flush();
        generator.close();
        isClosed = true;
    }
}