package com.fasterxml.jackson.core.json;

import com.fasterxml.jackson.core.*;

Extension of JsonStreamContext, which implements core methods needed, and also exposes more complete API to parser implementation classes. /**
 * Extension of {@link JsonStreamContext}, which implements
 * core methods needed, and also exposes
 * more complete API to parser implementation classes.
 */
public final class JsonReadContext extends JsonStreamContext
{
    // // // Configuration

    
Parent context for this context; null for root context.
/**
     * Parent context for this context; null for root context.
     */
    protected final JsonReadContext _parent;
    
    // // // Optional duplicate detection

    protected DupDetector _dups;

    /*
    /**********************************************************
    /* Simple instance reuse slots; speeds up things
    /* a bit (10-15%) for docs with lots of small
    /* arrays/objects (for which allocation was
    /* visible in profile stack frames)
    /**********************************************************
     */

    protected JsonReadContext _child;

    /*
    /**********************************************************
    /* Location/state information (minus source reference)
    /**********************************************************
     */

    protected String _currentName;

    
Since:
2.5/**
     * @since 2.5
     */
    protected Object _currentValue;
    
    protected int _lineNr;
    protected int _columnNr;

    /*
    /**********************************************************
    /* Instance construction, config, reuse
    /**********************************************************
     */

    public JsonReadContext(JsonReadContext parent, DupDetector dups, int type, int lineNr, int colNr) {
        super();
        _parent = parent;
        _dups = dups;
        _type = type;
        _lineNr = lineNr;
        _columnNr = colNr;
        _index = -1;
    }

    protected void reset(int type, int lineNr, int colNr) {
        _type = type;
        _index = -1;
        _lineNr = lineNr;
        _columnNr = colNr;
        _currentName = null;
        _currentValue = null;
        if (_dups != null) {
            _dups.reset();
        }
    }

    /*
    public void trackDups(JsonParser p) {
        _dups = DupDetector.rootDetector(p);
    }
    */

    public JsonReadContext withDupDetector(DupDetector dups) {
        _dups = dups;
        return this;
    }

    @Override
    public Object getCurrentValue() {
        return _currentValue;
    }

    @Override
    public void setCurrentValue(Object v) {
        _currentValue = v;
    }

    /*
    /**********************************************************
    /* Factory methods
    /**********************************************************
     */

    public static JsonReadContext createRootContext(int lineNr, int colNr, DupDetector dups) {
        return new JsonReadContext(null, dups, TYPE_ROOT, lineNr, colNr);
    }

    public static JsonReadContext createRootContext(DupDetector dups) {
        return new JsonReadContext(null, dups, TYPE_ROOT, 1, 0);
    }

    public JsonReadContext createChildArrayContext(int lineNr, int colNr) {
        JsonReadContext ctxt = _child;
        if (ctxt == null) {
            _child = ctxt = new JsonReadContext(this,
                    (_dups == null) ? null : _dups.child(), TYPE_ARRAY, lineNr, colNr);
        } else {
            ctxt.reset(TYPE_ARRAY, lineNr, colNr);
        }
        return ctxt;
    }

    public JsonReadContext createChildObjectContext(int lineNr, int colNr) {
        JsonReadContext ctxt = _child;
        if (ctxt == null) {
            _child = ctxt = new JsonReadContext(this,
                    (_dups == null) ? null : _dups.child(), TYPE_OBJECT, lineNr, colNr);
            return ctxt;
        }
        ctxt.reset(TYPE_OBJECT, lineNr, colNr);
        return ctxt;
    }

    /*
    /**********************************************************
    /* Abstract method implementations, overrides
    /**********************************************************
     */

    @Override public String getCurrentName() { return _currentName; }

    // @since 2.9
    @Override public boolean hasCurrentName() { return _currentName != null; }

    @Override public JsonReadContext getParent() { return _parent; }

    @Override
    public JsonLocation getStartLocation(Object srcRef) {
        // We don't keep track of offsets at this level (only reader does)
        long totalChars = -1L;
        return new JsonLocation(srcRef, totalChars, _lineNr, _columnNr);
    }

    /*
    /**********************************************************
    /* Extended API
    /**********************************************************
     */

    
Method that can be used to both clear the accumulated references (specifically value set with setCurrentValue(Object)) that should not be retained, and returns parent (as would getParent() do). Typically called when closing the active context when encountering JsonToken.END_ARRAY or JsonToken.END_OBJECT. 
Since:
2.7/**
     * Method that can be used to both clear the accumulated references
     * (specifically value set with {@link #setCurrentValue(Object)})
     * that should not be retained, and returns parent (as would
     * {@link #getParent()} do). Typically called when closing the active
     * context when encountering {@link JsonToken#END_ARRAY} or
     * {@link JsonToken#END_OBJECT}.
     *
     * @since 2.7
     */
    public JsonReadContext clearAndGetParent() {
        _currentValue = null;
        // could also clear the current name, but seems cheap enough to leave?
        return _parent;
    }

    public DupDetector getDupDetector() {
        return _dups;
    }

    /*
    /**********************************************************
    /* State changes
    /**********************************************************
     */

    public boolean expectComma() {
        /* Assumption here is that we will be getting a value (at least
         * before calling this method again), and
         * so will auto-increment index to avoid having to do another call
         */
        int ix = ++_index; // starts from -1
        return (_type != TYPE_ROOT && ix > 0);
    }

    public void setCurrentName(String name) throws JsonProcessingException {
        _currentName = name;
        if (_dups != null) { _checkDup(_dups, name); }
    }

    private void _checkDup(DupDetector dd, String name) throws JsonProcessingException {
        if (dd.isDup(name)) {
            Object src = dd.getSource();
            throw new JsonParseException(((src instanceof JsonParser) ? ((JsonParser) src) : null),
                    "Duplicate field '"+name+"'");
        }
    }
}