package com.fasterxml.jackson.databind.node; import java.util.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.JsonNode; /** * Helper class used by {@link TreeTraversingParser} to keep track * of current location within traversed JSON tree. */ abstract class NodeCursor extends JsonStreamContext { /** * Parent cursor of this cursor, if any; null for root * cursors. */ protected final NodeCursor _parent; /** * Current field name */ protected String _currentName; /** * @since 2.5 */ protected java.lang.Object _currentValue; public NodeCursor(int contextType, NodeCursor p) { super(); _type = contextType; _index = -1; _parent = p; } /* /********************************************************** /* JsonStreamContext impl /********************************************************** */ // note: co-variant return type @Override public final NodeCursor getParent() { return _parent; } @Override public final String getCurrentName() { return _currentName; } /** * @since 2.0 */ public void overrideCurrentName(String name) { _currentName = name; } @Override public java.lang.Object getCurrentValue() { return _currentValue; } @Override public void setCurrentValue(java.lang.Object v) { _currentValue = v; } /* /********************************************************** /* Extended API /********************************************************** */ public abstract JsonToken nextToken(); public abstract JsonToken nextValue(); public abstract JsonToken endToken(); public abstract JsonNode currentNode(); public abstract boolean currentHasChildren(); /** * Method called to create a new context for iterating all * contents of the current structured value (JSON array or object) */ public final NodeCursor iterateChildren() { JsonNode n = currentNode(); if (n == null) throw new IllegalStateException("No current node"); if (n.isArray()) { // false since we have already returned START_ARRAY return new ArrayCursor(n, this); } if (n.isObject()) { return new ObjectCursor(n, this); } throw new IllegalStateException("Current node of type "+n.getClass().getName()); } /* /********************************************************** /* Concrete implementations /********************************************************** */ /** * Context matching root-level value nodes (i.e. anything other * than JSON Object and Array). * Note that context is NOT created for leaf values. */ protected final static class RootCursor extends NodeCursor { protected JsonNode _node; protected boolean _done = false; public RootCursor(JsonNode n, NodeCursor p) { super(JsonStreamContext.TYPE_ROOT, p); _node = n; } @Override public void overrideCurrentName(String name) { } @Override public JsonToken nextToken() { if (!_done) { _done = true; return _node.asToken(); } _node = null; return null; } @Override public JsonToken nextValue() { return nextToken(); } @Override public JsonToken endToken() { return null; } @Override public JsonNode currentNode() { return _node; } @Override public boolean currentHasChildren() { return false; } } /** * Cursor used for traversing non-empty JSON Array nodes */ protected final static class ArrayCursor extends NodeCursor { protected Iterator<JsonNode> _contents; protected JsonNode _currentNode; public ArrayCursor(JsonNode n, NodeCursor p) { super(JsonStreamContext.TYPE_ARRAY, p); _contents = n.elements(); } @Override public JsonToken nextToken() { if (!_contents.hasNext()) { _currentNode = null; return null; } _currentNode = _contents.next(); return _currentNode.asToken(); } @Override public JsonToken nextValue() { return nextToken(); } @Override public JsonToken endToken() { return JsonToken.END_ARRAY; } @Override public JsonNode currentNode() { return _currentNode; } @Override public boolean currentHasChildren() { // note: ONLY to be called for container nodes return ((ContainerNode<?>) currentNode()).size() > 0; } } /** * Cursor used for traversing non-empty JSON Object nodes */ protected final static class ObjectCursor extends NodeCursor { protected Iterator<Map.Entry<String, JsonNode>> _contents; protected Map.Entry<String, JsonNode> _current; protected boolean _needEntry; public ObjectCursor(JsonNode n, NodeCursor p) { super(JsonStreamContext.TYPE_OBJECT, p); _contents = ((ObjectNode) n).fields(); _needEntry = true; } @Override public JsonToken nextToken() { // Need a new entry? if (_needEntry) { if (!_contents.hasNext()) { _currentName = null; _current = null; return null; } _needEntry = false; _current = _contents.next(); _currentName = (_current == null) ? null : _current.getKey(); return JsonToken.FIELD_NAME; } _needEntry = true; return _current.getValue().asToken(); } @Override public JsonToken nextValue() { JsonToken t = nextToken(); if (t == JsonToken.FIELD_NAME) { t = nextToken(); } return t; } @Override public JsonToken endToken() { return JsonToken.END_OBJECT; } @Override public JsonNode currentNode() { return (_current == null) ? null : _current.getValue(); } @Override public boolean currentHasChildren() { // note: ONLY to be called for container nodes return ((ContainerNode<?>) currentNode()).size() > 0; } } }