com.fasterxml.jackson.core.json.JsonWriteContext Maven / Gradle / Ivy
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package com.fasterxml.jackson.core.json;
import com.fasterxml.jackson.core.*;
/**
* Extension of {@link JsonStreamContext}, which implements
* core methods needed, and also exposes
* more complete API to generator implementation classes.
*/
public class JsonWriteContext extends JsonStreamContext
{
// // // Return values for writeValue()
public final static int STATUS_OK_AS_IS = 0;
public final static int STATUS_OK_AFTER_COMMA = 1;
public final static int STATUS_OK_AFTER_COLON = 2;
public final static int STATUS_OK_AFTER_SPACE = 3; // in root context
public final static int STATUS_EXPECT_VALUE = 4;
public final static int STATUS_EXPECT_NAME = 5;
/**
* Parent context for this context; null for root context.
*/
protected final JsonWriteContext _parent;
// // // Optional duplicate detection
protected DupDetector _dups;
/*
/**********************************************************
/* Simple instance reuse slots; speed up things a bit (10-15%)
/* for docs with lots of small arrays/objects
/**********************************************************
*/
protected JsonWriteContext _child;
/*
/**********************************************************
/* Location/state information (minus source reference)
/**********************************************************
*/
/**
* Name of the field of which value is to be written; only
* used for OBJECT contexts
*/
protected String _currentName;
/**
* @since 2.5
*/
protected Object _currentValue;
/**
* Marker used to indicate that we just wrote a name, and
* now expect a value to write
*/
protected boolean _gotName;
/*
/**********************************************************
/* Life-cycle
/**********************************************************
*/
protected JsonWriteContext(int type, JsonWriteContext parent, DupDetector dups) {
super();
_type = type;
_parent = parent;
_dups = dups;
_index = -1;
}
/* @since 2.10 */
protected JsonWriteContext(int type, JsonWriteContext parent, DupDetector dups,
Object currValue) {
super();
_type = type;
_parent = parent;
_dups = dups;
_index = -1;
_currentValue = currValue;
}
/**
* Internal method to allow instance reuse: DO NOT USE unless you absolutely
* know what you are doing.
* Clears up state (including "current value"), changes type to one specified;
* resets current duplicate-detection state (if any).
* Parent link left as-is since it is {@code final}.
*
* NOTE: Public since 2.12.
*
* @param type Type to assign to this context node
*
* @return This context instance to allow call-chaining
*/
public JsonWriteContext reset(int type) {
_type = type;
_index = -1;
_currentName = null;
_gotName = false;
_currentValue = null;
if (_dups != null) { _dups.reset(); }
return this;
}
/**
* Internal method to allow instance reuse: DO NOT USE unless you absolutely
* know what you are doing.
* Clears up state, changes type to one specified, assigns "current value";
* resets current duplicate-detection state (if any).
* Parent link left as-is since it is {@code final}.
*
* NOTE: Public since 2.12.
*
* @param type Type to assign to this context node
* @param currValue Current value to assign to this context node
*
* @return This context instance to allow call-chaining
*
* @since 2.10
*/
public JsonWriteContext reset(int type, Object currValue) {
_type = type;
_index = -1;
_currentName = null;
_gotName = false;
_currentValue = currValue;
if (_dups != null) { _dups.reset(); }
return this;
}
public JsonWriteContext withDupDetector(DupDetector dups) {
_dups = dups;
return this;
}
@Override
public Object getCurrentValue() {
return _currentValue;
}
@Override
public void setCurrentValue(Object v) {
_currentValue = v;
}
/*
/**********************************************************
/* Factory methods
/**********************************************************
*/
/**
* @deprecated Since 2.3; use method that takes argument
*
* @return Context instance created
*/
@Deprecated
public static JsonWriteContext createRootContext() { return createRootContext(null); }
public static JsonWriteContext createRootContext(DupDetector dd) {
return new JsonWriteContext(TYPE_ROOT, null, dd);
}
public JsonWriteContext createChildArrayContext() {
JsonWriteContext ctxt = _child;
if (ctxt == null) {
_child = ctxt = new JsonWriteContext(TYPE_ARRAY, this,
(_dups == null) ? null : _dups.child());
return ctxt;
}
return ctxt.reset(TYPE_ARRAY);
}
/* @since 2.10 */
public JsonWriteContext createChildArrayContext(Object currValue) {
JsonWriteContext ctxt = _child;
if (ctxt == null) {
_child = ctxt = new JsonWriteContext(TYPE_ARRAY, this,
(_dups == null) ? null : _dups.child(), currValue);
return ctxt;
}
return ctxt.reset(TYPE_ARRAY, currValue);
}
public JsonWriteContext createChildObjectContext() {
JsonWriteContext ctxt = _child;
if (ctxt == null) {
_child = ctxt = new JsonWriteContext(TYPE_OBJECT, this,
(_dups == null) ? null : _dups.child());
return ctxt;
}
return ctxt.reset(TYPE_OBJECT);
}
/* @since 2.10 */
public JsonWriteContext createChildObjectContext(Object currValue) {
JsonWriteContext ctxt = _child;
if (ctxt == null) {
_child = ctxt = new JsonWriteContext(TYPE_OBJECT, this,
(_dups == null) ? null : _dups.child(), currValue);
return ctxt;
}
return ctxt.reset(TYPE_OBJECT, currValue);
}
@Override public final JsonWriteContext getParent() { return _parent; }
@Override public final String getCurrentName() { return _currentName; }
// @since 2.9
@Override public boolean hasCurrentName() { return _currentName != null; }
/**
* 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}.
*
* @return Parent context of this context node, if any; {@code null} for root context
*
* @since 2.7
*/
public JsonWriteContext clearAndGetParent() {
_currentValue = null;
// could also clear the current name, but seems cheap enough to leave?
return _parent;
}
public DupDetector getDupDetector() {
return _dups;
}
/**
* Method that writer is to call before it writes a name of Object property.
*
* @param name Property name being written
*
* @return Index of the field entry (0-based)
*
* @throws JsonProcessingException if duplicate check restriction is violated
*/
public int writeFieldName(String name) throws JsonProcessingException {
if ((_type != TYPE_OBJECT) || _gotName) {
return STATUS_EXPECT_VALUE;
}
_gotName = true;
_currentName = name;
if (_dups != null) { _checkDup(_dups, name); }
return (_index < 0) ? STATUS_OK_AS_IS : STATUS_OK_AFTER_COMMA;
}
private final void _checkDup(DupDetector dd, String name) throws JsonProcessingException {
if (dd.isDup(name)) {
Object src = dd.getSource();
throw new JsonGenerationException("Duplicate field '"+name+"'",
((src instanceof JsonGenerator) ? ((JsonGenerator) src) : null));
}
}
public int writeValue() {
// Most likely, object:
if (_type == TYPE_OBJECT) {
if (!_gotName) {
return STATUS_EXPECT_NAME;
}
_gotName = false;
++_index;
return STATUS_OK_AFTER_COLON;
}
// Ok, array?
if (_type == TYPE_ARRAY) {
int ix = _index;
++_index;
return (ix < 0) ? STATUS_OK_AS_IS : STATUS_OK_AFTER_COMMA;
}
// Nope, root context
// No commas within root context, but need space
++_index;
return (_index == 0) ? STATUS_OK_AS_IS : STATUS_OK_AFTER_SPACE;
}
}