''' The query module provides functions for searching collections of Bokeh
models for instances that match specified criteria.
'''
from __future__ import absolute_import
from six import string_types
[docs]class OR(object):
''' Form disjunctions from other query predicates.
Construct an ``OR`` expression by making a dict with ``OR`` as the key,
and a list of other query expressions as the value:
.. code-block:: python
# matches any Axis subclasses or models with .name == "mycircle"
{ OR: [dict(type=Axis), dict(name="mycircle")] }
'''
pass
[docs]class IN(object):
''' Predicate to test if property values are in some collection.
Construct and ``IN`` predicate as a dict with ``IN`` as the key,
and a list of values to check against.
.. code-block:: python
# matches any models with .name in ['a', 'mycircle', 'myline']
dict(name={ IN: ['a', 'mycircle', 'myline'] })
'''
pass
[docs]class GT(object):
''' Predicate to test if property values are greater than some value.
Construct and ``GT`` predicate as a dict with ``GT`` as the key,
and a value to compare against.
.. code-block:: python
# matches any models with .size > 10
dict(size={ GT: 10 })
'''
pass
[docs]class LT(object):
''' Predicate to test if property values are less than some value.
Construct and ``LT`` predicate as a dict with ``LT`` as the key,
and a value to compare against.
.. code-block:: python
# matches any models with .size < 10
dict(size={ LT: 10 })
'''
pass
[docs]class EQ(object):
''' Predicate to test if property values are equal to some value.
Construct and ``EQ`` predicate as a dict with ``EQ`` as the key,
and a value to compare against.
.. code-block:: python
# matches any models with .size == 10
dict(size={ EQ: 10 })
'''
pass
[docs]class GEQ(object):
''' Predicate to test if property values are greater than or equal to
some value.
Construct and ``GEQ`` predicate as a dict with ``GEQ`` as the key,
and a value to compare against.
.. code-block:: python
# matches any models with .size >= 10
dict(size={ GEQ: 10 })
'''
pass
[docs]class LEQ(object):
''' Predicate to test if property values are less than or equal to
some value.
Construct and ``LEQ`` predicate as a dict with ``LEQ`` as the key,
and a value to compare against.
.. code-block:: python
# matches any models with .size <= 10
dict(size={ LEQ: 10 })
'''
pass
[docs]class NEQ(object):
''' Predicate to test if property values are unequal to some value.
Construct and ``NEQ`` predicate as a dict with ``NEQ`` as the key,
and a value to compare against.
.. code-block:: python
# matches any models with .size != 10
dict(size={ NEQ: 10 })
'''
pass
# realizations of the abstract predicate operators
_operators = {
IN: lambda x, y: x in y,
GT: lambda x, y: x > y,
LT: lambda x, y: x < y,
EQ: lambda x, y: x == y,
GEQ: lambda x, y: x >= y,
LEQ: lambda x, y: x <= y,
NEQ: lambda x, y: x != y,
}
# realization of the OR operator
def _or(obj, selectors):
return any(match(obj, selector) for selector in selectors)
[docs]def match(obj, selector, context=None):
''' Test whether a given Bokeh model matches a given selector.
Args:
obj (Model) : object to test
selector (JSON-like) : query selector
context (dict) : kwargs to supply callable query attributes
Returns:
bool : True if the object matches, False otherwise
In general, the selectors have the form:
.. code-block:: python
{ attrname : predicate }
Where a predicate is constructed from the operators ``EQ``, ``GT``, etc.
and is used to compare against values of model attributes named
``attrname``.
For example:
.. code-block:: python
>>> from bokeh.plotting import figure
>>> p = figure(plot_width=400)
>>> match(p, {'plot_width': {EQ: 400}})
True
>>> match(p, {'plot_width': {GT: 500}})
False
There are two selector keys that are handled especially. The first
is 'type', which will do an isinstance check:
.. code-block:: python
>>> from bokeh.plotting import figure
>>> from bokeh.models import Axis
>>> p = figure()
>>> match(p.xaxis[0], {'type': Axis})
True
>>> match(p.title, {'type': Axis})
False
There is also a ``'tags'`` attribute that ``Model`` objects have, that
is a list of user-supplied values. The ``'tags'`` selector key can be
used to query against this list of tags. An object matches if any of the
tags in the selector match any of the tags on the object:
.. code-block:: python
>>> from bokeh.plotting import figure
>>> p = figure(tags = ["my plot", 10])
>>> match(p, {'tags': "my plot"})
True
>>> match(p, {'tags': ["my plot", 10]})
True
>>> match(p, {'tags': ["foo"]})
False
'''
context = context or {}
for key, val in selector.items():
# test attributes
if isinstance(key, string_types):
# special case 'type'
if key == "type":
# type supports IN, check for that first
if isinstance(val, dict) and list(val.keys()) == [IN]:
if not any(isinstance(obj, x) for x in val[IN]): return False
# otherwise just check the type of the object against val
elif not isinstance(obj, val): return False
# special case 'tag'
elif key == 'tags':
if isinstance(val, string_types):
if val not in obj.tags: return False
else:
try:
if not set(val) & set(obj.tags): return False
except TypeError:
if val not in obj.tags: return False
# if the object doesn't have the attr, it doesn't match
elif not hasattr(obj, key): return False
# if the value to check is a dict, recurse
else:
attr = getattr(obj, key)
if callable(attr):
try:
if not attr(val, **context): return False
except:
return False
elif isinstance(val, dict):
if not match(attr, val, context): return False
else:
if attr != val: return False
# test OR conditionals
elif key is OR:
if not _or(obj, val): return False
# test operands
elif key in _operators:
if not _operators[key](obj, val): return False
else:
raise ValueError("malformed query selector")
return True
[docs]def find(objs, selector, context=None):
''' Query a collection of Bokeh models and yield any that match the
a selector.
Args:
obj (Model) : object to test
selector (JSON-like) : query selector
context (dict) : kwargs to supply callable query attributes
Yields:
Model : objects that match the query
Queries are specified as selectors similar to MongoDB style query
selectors, as described for :func:`~bokeh.core.query.match`.
Examples:
.. code-block:: python
# find all objects with type Grid
find(p.references(), {'type': Grid})
# find all objects with type Grid or Axis
find(p.references(), {OR: [
{'type': Grid}, {'type': Axis}
]})
# same query, using IN operator
find(p.references(), {'type': {IN: [Grid, Axis]}})
# find all plot objects on the 'left' layout of the Plot
# here layout is a method that takes a plot as context
find(p.references(), {'layout': 'left'}, {'plot': p})
'''
return (obj for obj in objs if match(obj, selector, context))
