new examples

1 files changed, 127 insertions, 0 deletions

diff --git a/examples/adjacencytree/byroot_tree.py b/examples/adjacencytree/byroot_tree.py
new file mode 100644
index 000000000..116305164
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+++ b/examples/adjacencytree/byroot_tree.py
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+from sqlalchemy.mapper import *
+from sqlalchemy.schema import *
+from sqlalchemy.sql import *
+import sqlalchemy.util as util
+import tables
+import string, sys
+
+"""a more advanced example of basic_tree.py.  illustrates MapperExtension objects which
+add application-specific functionality to a Mapper object."""
+
+class NodeList(util.OrderedDict):
+    """extends an Ordered Dictionary, which is just a dictionary that returns its keys and values
+    in order upon iteration.  Adds functionality to automatically associate 
+    the parent of a TreeNode with itself, upon append to the parent's list of child nodes."""
+    def __init__(self, parent):
+        util.OrderedDict.__init__(self)
+        self.parent = parent
+    def append(self, node):
+        node.parent = self.parent
+        node._set_root(self.parent.root)
+        self[node.name] = node
+    def __iter__(self):
+        return iter(self.values())
+
+class TreeNode(object):
+    """a rich Tree class which includes path-based operations"""
+    def __init__(self, name):
+        self.children = NodeList(self)
+        self.name = name
+        self.root = self
+        self.parent = None
+        self.id = None
+        self.parent_id = None
+        self.root_id=None
+    def _set_root(self, root):
+        self.root = root
+        for c in self.children:
+            c._set_root(root)
+    def get_child_by_path(self, path):
+        node = self
+        try:
+            for token in path.split('/'):
+                node = node.children[token]
+            else:
+                return node
+        except KeyError:
+            return None
+    def append(self, node):
+        if isinstance(node, str):
+            self.children.append(TreeNode(node))
+        else:
+            self.children.append(node)
+    def _get_path(self):
+        if self.parent is None:
+            return '/'
+        else:
+            return self.parent._get_path() + self.name + '/'
+    path = property(lambda s: s._path())
+    def __str__(self):
+        return self._getstring(0, False)
+    def _getstring(self, level, expand = False):
+        s = ('  ' * level) + "%s (%s,%s,%s)" % (self.name, self.id,self.parent_id,self.root_id) + '\n'
+        if expand:
+            s += string.join([n._getstring(level+1, True) for n in self.children.values()], '')
+        return s
+        
+class TreeLoader(MapperExtension):
+    def create_instance(self, mapper, row, imap, class_):
+        return TreeNode(row[mapper.c.name.label])
+    def after_insert(self, mapper, instance):
+        if instance.root is instance:
+            mapper.primarytable.update(TreeNode.c.id==instance.id, values=dict(root_node_id=instance.id)).execute()
+            instance.root_id = instance.id
+    def append_result(self, mapper, row, imap, result, instance, populate_existing=False):
+        if instance.parent_id is None:
+            result.append(instance)
+        else:
+            parentnode = imap[mapper.identity_key(instance.parent_id)]
+            parentnode.children.append_nohistory(instance)
+        return False
+            
+# define the mapper.  we will make "convenient" property
+# names vs. the more verbose names in the table definition
+
+TreeNode.mapper=assignmapper(tables.trees, properties=dict(
+    id=tables.trees.c.node_id,
+    name=tables.trees.c.node_name,
+    parent_id=tables.trees.c.parent_node_id,
+    root_id=tables.trees.c.root_node_id,
+    root=relation(TreeNode, primaryjoin=tables.trees.c.root_node_id==tables.trees.c.node_id, thiscol=tables.trees.c.root_node_id, lazy=None, uselist=False),
+    children=relation(TreeNode, primaryjoin=tables.trees.c.parent_node_id==tables.trees.c.node_id, thiscol=tables.trees.c.node_id, lazy=None, uselist=True, private=True),
+), extension = TreeLoader())
+TreeNode.mapper
+
+node2 = TreeNode('node2')
+node2.append('subnode1')
+node = TreeNode('rootnode')
+#node.root = node
+node.append('node1')
+node.append(node2)
+node.append('node3')
+node.children['node2'].append('subnode2')
+print node._getstring(0, True)
+objectstore.commit()
+#raise "hi"
+node.append('node4')
+node.children['node4'].append('subnode3')
+node.children['node4'].append('subnode4')
+node.children['node4'].children['subnode3'].append('subsubnode1')
+print node._getstring(0, True)
+#raise "hi"
+del node.children['node1']
+objectstore.commit()
+
+id = node.id
+
+objectstore.clear()
+print "\n\n\n"
+t = TreeNode.mapper.select(TreeNode.c.root_id==id, order_by=[TreeNode.c.id])[0]
+
+print t._getstring(0, True)
+objectstore.delete(t)
+objectstore.commit()
+
+
+
+