Android Criteria

Criteria is a small and simple library for filtering in memory data.

Project News

• Version 0.1.2 released, added test code and minor fixes.
• Just released version 0.1.1.

Features

• List filtering
• Single item verification
• And, Or, Xor and Not support

Android 4.0.3 and above support

Usage

Import into your gradle project:

dependencies {
   ...
   compile 'com.rakangsoftware.criteria:criteria:0.1.2'
   ...
}

First you need to have your model object. To make this example clean and easy I will use String as model.

Data to use

Let's setup a list with names.

List<String> data = new ArrayList<>();
data.add("Silas");
data.add("Carmen");
data.add("Joan");
data.add("Michele");
data.add("Kari");
data.add("Marjorie");
data.add("Johnette");
data.add("Jason");
data.add("Marya");
data.add("Ola");

Implement a Criterion

Since Criteria don't implement any real filter classes we need to create one our self, here is one for checking if a name contains a string.

public class NameCriterion implements Criterion<String> {

   private String mQuery;

   public NameCriterion(final String query) {
       mQuery = query;
   }

   @Override
   public List<String> meet(final List<String> objects) {
       List<String> result = new ArrayList<>();
       for (String name : objects) {
           if (name.toLowerCase().contains(mQuery)) {
               result.add(name);
           }
       }
       return result;
   }

   @Override
   public boolean meet(final String name) {
       return name.toLowerCase().contains(mQuery);
   }
}

How to use

This code snippet will return a list with all names containing the letter 'a'.

Criterion contains = new NameCriterion("a");
List<String> result = contains.meet(data);

How to AndCriteria

This code snippet will return a list with all names containing the letters 'a' and 'r'.

Criterion<String> contains = new AndCriteria<>(new NameCriterion("a"), new NameCriterion("r"));
List<String>      result   = contains.meet(getNames());

This code snippet will return a list with all names containing the letters 'a', 'r' and 'p'.

Criterion<String> contains = new AndCriteria<>(new NameCriterion("a"), new NameCriterion("r"), new NameCriterion("p"));
List<String>      result   = contains.meet(getNames());

How to OrCriteria

This code snippet will return a list with all names containing the letter 'a' or 'r'.

Criterion<String> contains = new OrCriteria<>(new NameCriterion("a"), new NameCriterion("r"));
List<String>      result   = contains.meet(data);

This code snippet will return a list with all names containing the letter 'a', 'r' or 'p'.

CriterionString> contains = new OrCriteria<>(new NameCriterion("a"), new NameCriterion("r"), new NameCriterion("p"));
List<String>     result   = contains.meet(data);

How to XorCriteria

This code snippet will return a list with all names containing the letter 'a' or 'r' but not both of them.

Criterion<String> contains = new XorCriteria<>(new NameCriterion("a"), new NameCriterion("r"));
List<String>      result   = contains.meet(data);

This code snippet will return a list with all names containing the any of the letters 'a', 'r' or 'p' but only one of them.

Criterion<String> contains = new XorCriteria<>(new NameCriterion("a"), new NameCriterion("r"), new NameCriterion("p"));
List<String>      result   = contains.meet(data);

How to NotCriteria

This code snippet will return a list with all names not containing the letter 'a'.

Criterion<String>    contains = new NotCriterion<>(new NameCriterion("a"));
List<String>         result   = contains.meet(getNames());

Nested criteria.

Let's say we want all name containing 'a' or 'e' but not 'c'.

AndCriterion
|-- NotCriterion
|	`-- NameCriterion ('c')
`-- OrCriterion
 	|-- NameCriterion ('a')
 	`-- NameCriterion ('r')

Criterion<String> orCriterion = new OrCriteria<>(new NameCriterion("a"), new NameCriterion("r"));
Criterion<String> notCriterion = new NotCriterion<>(new NameCriterion("c"));
Criterion<String> andCriterion = new AndCriteria<>(orCriterion, notCriterion);
List<String> result = andCriterion.meet(data);

License

Copyright 2017 Per-Erik Bergman

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.