Null Objects - Basic usage.

Author: rajdeeptarat

.editorconfig

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+# EditorConfig is awesome: http://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+# Matches multiple files with brace expansion notation
+# Set default charset
+[*]
+charset = utf-8
+
+# 4 space indentation
+[*]
+indent_style = space
+indent_size = 4
+
+# Matches the exact files either package.json or .travis.yml
+[{package.json,.travis.yml}]
+indent_style = space
+indent_size = 2

.gitignore

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+/vendor
+composer.phar
+composer.lock
+.DS_Store

LICENSE.md

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+The MIT License (MIT)
+
+Copyright (c) 2016 Rajdeep Tarat <[email protected]>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# Null Object for PHP
+
+Allows the user to call the null object which handles all calls silently and returns sensible defaults.
+The returned object can be type cast to return the following values:
+
+- String - ""
+- Integer - 0
+- Float or Real - 0.0
+- Array - []
+- Boolean  - False
+
+## Installation
+
+Run the following to install:
+
+```composer require conceptbyte/null-object```
+
+## Usage
+The null object can be created in one of the following methods:
+- Named constructor: ```NullObject::create()```
+- Helper function: ```no()```
+
+Both will return an instance of the class.
+
+## Quirks
+PHP does not allow modifying the behaviour of casting a class to boolean.
+A simple hack is to use the SimpleXMLElement class which can return false when passed
+an empty XML tag.

composer.json

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+{
+    "name": "conceptbyte/null-object",
+    "description": "A Null Object for PHP.",
+    "keywords": ["null-object", "null-object-pattern", "null"],
+    "type": "package",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Rajdeep Tarat",
+            "email": "[email protected]",
+            "homepage": "http://rajdeeptarat.com"
+        }
+    ],
+    "require": {
+        "php": ">=5.5.9"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^5.4"
+    },
+    "autoload": {
+        "psr-4": {
+            "ConceptByte\\NullObject\\": "src"
+        },
+        "files": [
+            "src/helpers.php"
+        ]
+    },
+    "minimum-stability": "stable"
+}

phpunit.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false"
+         syntaxCheck="false">
+    <testsuites>
+        <testsuite name="Null Object Test Suite">
+            <directory suffix=".php">./tests/</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>

src/NullObject.php

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+<?php
+
+namespace ConceptByte\NullObject;
+
+class NullObject extends \SimpleXMLElement
+{
+
+    /**
+     * Named constructor to create the class
+     *
+     * @return static
+     */
+    public static function create()
+    {
+        return new static('<stupid></stupid>');
+    }
+
+    /**
+     * Handles casting to a string
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        return '';
+    }
+
+    /**
+     * Suppress function calls
+     *
+     * @param $name
+     * @param $arguments
+     */
+    public function __call($name, $arguments)
+    {
+        // Silence is golden
+    }
+
+    /**
+     * Suppress static method calls
+     *
+     * @param $name
+     * @param $arguments
+     */
+    public static function __callStatic($name, $arguments)
+    {
+        // Silence is golden
+    }
+
+    /**
+     * Suppress method calls
+     *
+     * @param \child $name
+     * @return \SimpleXMLElement[]|void
+     */
+    public function __get($name)
+    {
+        // Silence is golden
+    }
+}

src/helpers.php

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+<?php
+
+if (!function_exists('no')) {
+    /**
+     * Create a null object
+     *
+     * @return static
+     */
+    function no() {
+        return \ConceptByte\NullObject\NullObject::create();
+    }
+}

tests/NullObjectTest.php

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+<?php
+
+use ConceptByte\NullObject\NullObject;
+
+class NullObjectTest extends PHPUnit_Framework_TestCase
+{
+
+    /** @test */
+    public function it_should_return_an_empty_string()
+    {
+        $null = NullObject::create();
+        $this->assertEquals("", (string)$null->xyz);
+    }
+
+    /** @test */
+    public function it_should_return_zero_for_an_integer()
+    {
+        $null = NullObject::create();
+        $this->assertEquals(0, (int)$null->xyz);
+        $this->assertEquals(0, (integer)$null->xyz);
+    }
+
+    /** @test */
+    public function it_should_return_zero_for_a_float()
+    {
+        $null = NullObject::create();
+        $this->assertEquals(0.0, (float)$null->xyz);
+        $this->assertEquals(0.0, (real)$null->xyz);
+    }
+
+    /** @test */
+    public function it_should_return_false_for_a_boolean()
+    {
+        $null = NullObject::create();
+        $this->assertEquals(false, (bool)$null->xyz);
+        $this->assertEquals(false, (boolean)$null->xyz);
+    }
+
+    /** @test */
+    public function it_should_return_an_empty_array()
+    {
+        $null = NullObject::create();
+        $this->assertEquals([], (array)$null->xyz);
+    }
+
+    /** @test */
+    public function it_handles_both_methods_and_properties()
+    {
+        $null = NullObject::create();
+        $this->assertEquals([], (array)$null->xyz);
+        $this->assertEquals([], (array)$null->xyz());
+    }
+}