Class BerMutations

java.lang.Object

org.snmp4j.mcp.tool.snmp.ber.BerMutations

public final class BerMutations
extends Object

Applies declarative mutations and computes permutations over a BER node tree (the plain Map/List form parsed from the snmp_message_ber JSON).

Mutations and permutation dimensions address nodes with a small subset of JSON Pointer (RFC 6901): "" is the root, "/children/1/children/0" descends into arrays and object members. Supported operations set the encoder's per-node fields (see BerJsonEncoder): setTag, setValue, setValueHex, overrideLength, lengthForm, truncate, omit, appendHex, setRawHex, and flipBit (flip one bit of the addressed leaf's current content).

Since:

0.1.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	BerMutations.Expansion	Result of expanding a permutation spec.

Method Summary

Modifier and Type	Method	Description
static void	applyMutations(Object root, List<?> mutations)	Applies a list of mutation operations in order, in place, to root.
static void	applyOp(Object nodeObj, String op, Object value)	Applies a single operation to a target node.
static Object	deepCopy(Object node)	Deep-copies a Map/List/primitive tree so mutations don't touch the template.
static BerMutations.Expansion	expand(Object base, Map<String,Object> spec, int limit)	Expands a permutation spec into a set of mutated node trees.
static Object	resolveNode(Object root, String pointer)	Resolves a JSON Pointer against the tree and returns the addressed node.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

applyMutations

public static void applyMutations(Object root,
 List<?> mutations)

Applies a list of mutation operations in order, in place, to root.

Parameters:

root - the node tree

mutations - a list of maps, each {"path":..,"op":..,"value":..}

applyOp

public static void applyOp(Object nodeObj,
 String op,
 Object value)

Applies a single operation to a target node.

Parameters:

nodeObj - the target node (must be a JSON object)

op - the operation name

value - the operation argument (may be null)

expand

public static BerMutations.Expansion expand(Object base,
 Map<String,Object> spec,
 int limit)

Expands a permutation spec into a set of mutated node trees.

Parameters:

base - the template node tree (already mutated, if applicable)

spec - the permutation spec: {"mode":"cartesian|zip","limit":N,"dimensions":[...]}

limit - the maximum number of trees to produce

Returns:

the expansion result

resolveNode

public static Object resolveNode(Object root,
 String pointer)

Resolves a JSON Pointer against the tree and returns the addressed node.

Parameters:

root - the tree

pointer - an RFC 6901 pointer ("" for root)

Returns:

the addressed object

Throws:

IllegalArgumentException - if the pointer does not resolve

deepCopy

public static Object deepCopy(Object node)

Deep-copies a Map/List/primitive tree so mutations don't touch the template.

Parameters:

node - the node to deep-copy

Returns:

the deep-copy of the node