new examples

1 files changed, 107 insertions, 0 deletions

diff --git a/examples/adjacencytree/basic_tree.py b/examples/adjacencytree/basic_tree.py
new file mode 100644
index 000000000..c544ce662
--- /dev/null
+++ b/examples/adjacencytree/basic_tree.py
@@ -0,0 +1,107 @@
+from sqlalchemy.mapper import *
+from sqlalchemy.schema import *
+from sqlalchemy.sql import *
+import sqlalchemy.util as util
+import tables
+import string, sys
+
+"""a basic Adjacency List model tree."""
+
+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
+        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=None):
+        self.children = NodeList(self)
+        self.name = name
+        self.parent = None
+        self.id = None
+        self.parent_id = None
+    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)" % (self.name, self.id,self.parent_id) + '\n'
+        if expand:
+            s += string.join([n._getstring(level+1, True) for n in self.children.values()], '')
+        return s
+    def print_nodes(self):
+        return self._getstring(0, True)
+        
+# define the mapper.  we will make "convenient" property
+# names vs. the more verbose names in the table definition
+
+TreeNode.mapper=assignmapper(tables.trees, class_ = TreeNode, 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,
+    children=relation(TreeNode, primaryjoin=tables.trees.c.parent_node_id==tables.trees.c.node_id, thiscol=tables.trees.c.node_id, lazy=True, uselist=True, private=True),
+))
+
+
+node2 = TreeNode('node2')
+node2.append('subnode1')
+node = TreeNode('rootnode')
+node.append('node1')
+node.append(node2)
+node.append('node3')
+node.children['node2'].append('subnode2')
+print node.print_nodes()
+
+objectstore.commit()
+
+node.append('node4')
+node.children['node4'].append('subnode3')
+node.children['node4'].append('subnode4')
+node.children['node4'].children['subnode3'].append('subsubnode1')
+del node.children['node1']
+
+print node.print_nodes()
+
+objectstore.commit()
+
+id = node.id
+
+objectstore.clear()
+print "\n\n\n"
+
+t = TreeNode.mapper.select(TreeNode.c.id == id)[0]
+
+print t.print_nodes()
+objectstore.delete(t)
+objectstore.commit()
+
+
+
+