在做了所有这些预备之后，下面就是这种图形遍历的标准实现：
public static IObjectProfileNode profile (Object obj)
{
final IdentityHashMap visited = new IdentityHashMap ();
final ObjectProfileNode root = createProfileTree (obj, visited,
CLASS_METADATA_CACHE);
finishProfileTree (root);
return root;
}
private static ObjectProfileNode createProfileTree (Object obj,
IdentityHashMap visited,
Map metadataMap)
{
final ObjectProfileNode root = new ObjectProfileNode (null, obj, null);
final LinkedList queue = new LinkedList ();
queue.addFirst (root);
visited.put (obj, root);
final ClassAccessPrivilegedAction caAction =
new ClassAccessPrivilegedAction ();
final FieldAccessPrivilegedAction faAction =
new FieldAccessPrivilegedAction ();
while (! queue.isEmpty ())
{
final ObjectProfileNode node = (ObjectProfileNode) queue.removeFirst ();
obj = node.m_obj;
final Class objClass = obj.getClass ();
if (objClass.isArray ())
{
final int arrayLength = Array.getLength (obj);
final Class componentType = objClass.getComponentType ();
// Add shell pseudo-node:
final AbstractShellProfileNode shell =
new ArrayShellProfileNode (node, objClass, arrayLength);
shell.m_size = sizeofArrayShell (arrayLength, componentType);
node.m_shell = shell;
node.addFieldRef (shell);
if (! componentType.isPrimitive ())
{
// Traverse each array slot:
for (int i = 0; i < arrayLength; ++ i)
{
final Object ref = Array.get (obj, i);
if (ref != null)
{
ObjectProfileNode child =
(ObjectProfileNode) visited.get (ref);
if (child != null)
++ child.m_refcount;
else
{
child = new ObjectProfileNode (node, ref,
new ArrayIndexLink (node.m_link, i));
node.addFieldRef (child);
queue.addLast (child);
visited.put (ref, child);
}
}
}
}
}
else // the object is of a non-array type
{
final ClassMetadata metadata =
getClassMetadata (objClass, metadataMap, caAction, faAction);
final Field [] fields = metadata.m_refFields;
// Add shell pseudo-node:
final AbstractShellProfileNode shell =
new ObjectShellProfileNode (node,
metadata.m_primitiveFieldCount,
metadata.m_refFields.length);
shell.m_size = metadata.m_shellSize;
node.m_shell = shell;
node.addFieldRef (shell);
// Traverse all non-null ref fields:
for (int f = 0, fLimit = fields.length; f < fLimit; ++ f)
{
final Field field = fields [f];
final Object ref;
try // to get the field value:
{
ref = field.get (obj);
}
catch (Exception e)
{
throw new RuntimeException ("cannot get field [" +
field.getName () + "] of class [" +
field.getDeclaringClass ().getName () +
"]: " + e.toString ());
}
if (ref != null)
{
ObjectProfileNode child =
(ObjectProfileNode) visited.get (ref);
if (child != null)
++ child.m_refcount;
else
{
child = new ObjectProfileNode (node, ref,
new ClassFieldLink (field));
node.addFieldRef (child);
queue.addLast (child);
visited.put (ref, child);
}
}
}
}
}
return root;
}
private static void finishProfileTree (ObjectProfileNode node)
{
final LinkedList queue = new LinkedList ();
IObjectProfileNode lastFinished = null;
while (node != null)
{
// Note that an unfinished nonshell node has its child count
// in m_size and m_children[0] is its shell node:
if ((node.m_size == 1) (lastFinished == node.m_children [1]))
{
node.finish ();
lastFinished = node;
}
else
{
queue.addFirst (node);
for (int i = 1; i < node.m_size; ++ i)
{
final IObjectProfileNode child = node.m_children [i];
queue.addFirst (child);
}
}
if (queue.isEmpty ())
return;
else
node = (ObjectProfileNode) queue.removeFirst ();
}
}
该代码是上一篇Java Q&A, "Attack of the Clones."使用的"通过反射克隆"实现的远亲。
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