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/* Jackson JSON-processor.
 *
 * Copyright (c) 2007- Tatu Saloranta, [email protected]
 */

package com.fasterxml.jackson.core;

import com.fasterxml.jackson.core.io.CharTypes;

/**
 * Shared base class for streaming processing contexts used during
 * reading and writing of Json content using Streaming API.
 * This context is also exposed to applications:
 * context object can be used by applications to get an idea of
 * relative position of the parser/generator within json content
 * being processed. This allows for some contextual processing: for
 * example, output within Array context can differ from that of
 * Object context.
 */
public abstract class JsonStreamContext
{
    // // // Type constants used internally

    protected final static int TYPE_ROOT = 0;
    protected final static int TYPE_ARRAY = 1;
    protected final static int TYPE_OBJECT = 2;

    protected int _type;

    /**
     * Index of the currently processed entry. Starts with -1 to signal
     * that no entries have been started, and gets advanced each
     * time a new entry is started, either by encountering an expected
     * separator, or with new values if no separators are expected
     * (the case for root context).
     */
    protected int _index;

    /*
    /**********************************************************
    /* Life-cycle
    /**********************************************************
     */

    protected JsonStreamContext() { }

    /**
     * Copy constructor used by sub-classes for creating copies for
     * buffering.
     *
     * @since 2.9
     */
    protected JsonStreamContext(JsonStreamContext base) {
        _type = base._type;
        _index = base._index;
    }

    /**
     * @since 2.9
     */
    protected JsonStreamContext(int type, int index) {
        _type = type;
        _index = index;
    }

    /*
    /**********************************************************
    /* Public API, accessors
    /**********************************************************
     */

    /**
     * Accessor for finding parent context of this context; will
     * return null for root context.
     */
    public abstract JsonStreamContext getParent();

    /**
     * Method that returns true if this context is an Array context;
     * that is, content is being read from or written to a Json Array.
     */
    public final boolean inArray() { return _type == TYPE_ARRAY; }

    /**
     * Method that returns true if this context is a Root context;
     * that is, content is being read from or written to without
     * enclosing array or object structure.
     */
    public final boolean inRoot() { return _type == TYPE_ROOT; }

    /**
     * Method that returns true if this context is an Object context;
     * that is, content is being read from or written to a Json Object.
     */
    public final boolean inObject() { return _type == TYPE_OBJECT; }

    /**
     * Method for accessing simple type description of current context;
     * either ROOT (for root-level values), OBJECT (for field names and
     * values of JSON Objects) or ARRAY (for values of JSON Arrays)
     *
     * @deprecated Since 2.8 use {@link #typeDesc} instead
     */
    @Deprecated // since 2.8
    public final String getTypeDesc() {
        switch (_type) {
        case TYPE_ROOT: return "ROOT";
        case TYPE_ARRAY: return "ARRAY";
        case TYPE_OBJECT: return "OBJECT";
        }
        return "?";
    }

    /**
     * @since 2.8
     */
    public String typeDesc() {
        switch (_type) {
        case TYPE_ROOT: return "root";
        case TYPE_ARRAY: return "Array";
        case TYPE_OBJECT: return "Object";
        }
        return "?";
    }

    /**
     * @return Number of entries that are complete and started.
     */
    public final int getEntryCount() { return _index + 1; }

    /**
     * @return Index of the currently processed entry, if any
     */
    public final int getCurrentIndex() { return (_index < 0) ? 0 : _index; }

    /**
     * Method that may be called to verify whether this context has valid index:
     * will return `false` before the first entry of Object context or before
     * first element of Array context; otherwise returns `true`.
     *
     * @since 2.9
     */
    public boolean hasCurrentIndex() { return _index >= 0; }

    /**
     * Method that may be called to check if this context is either:
     *
    *
  • Object, with at least one entry written (partially or completely) *
  • *
  • Array, with at least one entry written (partially or completely) *
  • *
* and if so, return `true`; otherwise return `false`. Latter case includes * Root context (always), and Object/Array contexts before any entries/elements * have been read or written. *

* Method is mostly used to determine whether this context should be used for * constructing {@link JsonPointer} * * @since 2.9 */ public boolean hasPathSegment() { if (_type == TYPE_OBJECT) { return hasCurrentName(); } else if (_type == TYPE_ARRAY) { return hasCurrentIndex(); } return false; } /** * Method for accessing name associated with the current location. * Non-null for FIELD_NAME and value events that directly * follow field names; null for root level and array values. */ public abstract String getCurrentName(); /** * @since 2.9 */ public boolean hasCurrentName() { return getCurrentName() != null; } /** * Method for accessing currently active value being used by data-binding * (as the source of streaming data to write, or destination of data being * read), at this level in hierarchy. *

* Note that "current value" is NOT populated (or used) by Streaming parser or generator; * it is only used by higher-level data-binding functionality. * The reason it is included here is that it can be stored and accessed hierarchically, * and gets passed through data-binding. * * @return Currently active value, if one has been assigned. * * @since 2.5 */ public Object getCurrentValue() { return null; } /** * Method to call to pass value to be returned via {@link #getCurrentValue}; typically * called indirectly through {@link JsonParser#setCurrentValue} * or {@link JsonGenerator#setCurrentValue}). * * @since 2.5 */ public void setCurrentValue(Object v) { } /** * Factory method for constructing a {@link JsonPointer} that points to the current * location within the stream that this context is for, excluding information about * "root context" (only relevant for multi-root-value cases) * * @since 2.9 */ public JsonPointer pathAsPointer() { return JsonPointer.forPath(this, false); } /** * Factory method for constructing a {@link JsonPointer} that points to the current * location within the stream that this context is for, optionally including * "root value index" * * @param includeRoot Whether root-value offset is included as the first segment or not; * * @since 2.9 */ public JsonPointer pathAsPointer(boolean includeRoot) { return JsonPointer.forPath(this, includeRoot); } /** * Optional method that may be used to access starting location of this context: * for example, in case of JSON `Object` context, offset at which `[` token was * read or written. Often used for error reporting purposes. * Implementations that do not keep track of such location are expected to return * {@link JsonLocation#NA}; this is what the default implementation does. * * @return Location pointing to the point where the context * start marker was found (or written); never `null`. *

* NOTE: demoted from JsonReadContext in 2.9, to allow use for * "non-standard" read contexts. * * @since 2.9 */ public JsonLocation getStartLocation(Object srcRef) { return JsonLocation.NA; } /** * Overridden to provide developer readable "JsonPath" representation * of the context. * * @since 2.9 */ @Override public String toString() { StringBuilder sb = new StringBuilder(64); switch (_type) { case TYPE_ROOT: sb.append("/"); break; case TYPE_ARRAY: sb.append('['); sb.append(getCurrentIndex()); sb.append(']'); break; case TYPE_OBJECT: default: sb.append('{'); String currentName = getCurrentName(); if (currentName != null) { sb.append('"'); CharTypes.appendQuoted(sb, currentName); sb.append('"'); } else { sb.append('?'); } sb.append('}'); break; } return sb.toString(); } }





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