Revision 1506827

DERBY-673: Get rid of the NodeFactory

Patch derby-673-nuke-ctypes-without-enum-3.

This patch removes the usage of the global nodeType integer (see
QueryTreeNode) defined by C_NodeType.java. After the removal of the
node factory, this global quantity whose use mimicked "instanceof" can
be discarded, mostly. For some node which represent several logical
node types, e.g. BinaryArithmeticOperatorNode which can represent for
example both + and minus, a new quantity, "kind" is introduced to
differentiate between the logical types of nodes.

We introduce a default method ValueNode#isSameNodeKind which the
classes that implement several kinds need to override to add the extra
kind check. This is then called from the isEquivalent overrides as
needed.

JavaDoc for isSameNodeKind:

/**
 * Some node classes represent several logical node types (to reduce
 * footprint), which we call kinds.
 * This means that implementations of {@link #isEquivalent()}
 * cannot always just use instanceof to check if the other node
 * represents the same kind. Hence this method needs to be
 * implemented by all node classes that represent several kinds.
 * It is only called from implementations of isEquivalent.
 *
 * @param other The other value node whose kind we want to compare with.
 * @return true if this and o represent the same
 *         logical node type, i.e. kind.
 */