Initial commit

.gitignore

@@ -0,0 +1,3 @@
+target
+.idea
+*.iml

LICENSE.txt

@@ -0,0 +1,20 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Paul Campbell
+ *
+ * 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.
+ */

pom.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <properties>
+        <kemitix-checkstyle-ruleset.version>2.3.0</kemitix-checkstyle-ruleset.version>
+        <kemitix-checkstyle-ruleset.level>5-complexity</kemitix-checkstyle-ruleset.level>
+        <junit.version>4.12</junit.version>
+        <assertj.version>3.6.2</assertj.version>
+    </properties>
+
+    <parent>
+    <groupId>net.kemitix</groupId>
+        <artifactId>kemitix-parent</artifactId>
+        <version>2.7.0</version>
+        <relativePath/>
+    </parent>
+    <artifactId>conditional</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>net.kemitix</groupId>
+                <artifactId>kemitix-checkstyle-ruleset-maven-plugin</artifactId>
+                <version>${kemitix-checkstyle-ruleset.version}</version>
+                <executions>
+                    <execution>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>${kemitix-checkstyle-ruleset.level}</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <pluginRepositories>
+        <pluginRepository>
+            <id>sevntu-maven</id>
+            <name>sevntu-maven</name>
+            <url>http://sevntu-checkstyle.github.io/sevntu.checkstyle/maven2</url>
+        </pluginRepository>
+    </pluginRepositories>
+</project>

src/main/java/net/kemitix/conditional/Condition.java

@@ -0,0 +1,139 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Paul Campbell
+ *
+ * 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.
+ */
+
+package net.kemitix.conditional;
+
+/**
+ * If-then-else in a functional-style.
+ *
+ * @author Paul Campbell (pcampbell@kemitix.net).
+ */
+public interface Condition {
+
+    /**
+     * Create a new {@code Condition}.
+     *
+     * @param clause the condition to test
+     *
+     * @return the Condition
+     */
+    static Condition where(final boolean clause) {
+        if (clause) {
+            return new TrueCondition();
+        }
+        return new FalseCondition();
+    }
+
+    /**
+     * Logically AND combine the current {@code Condition} with the clause.
+     *
+     * @param clause the condition to test
+     *
+     * @return the Condition
+     */
+    Condition and(boolean clause);
+
+    /**
+     * Logically OR combine the current {@code Condition} with the clause.
+     *
+     * @param clause the condition to test
+     *
+     * @return the Condition
+     */
+    Condition or(boolean clause);
+
+    /**
+     * Perform this response if the {@code Condition} is {@code true}.
+     *
+     * @param response the response to perform
+     *
+     * @return the Condition
+     */
+    Condition then(Runnable response);
+
+    /**
+     * Perform this response if the {@code Condition} is {@code false}.
+     *
+     * @param response the response to perform
+     */
+    void otherwise(Runnable response);
+
+    /**
+     * A {@code Condition} that has evaluated to {@code true}.
+     */
+    class TrueCondition implements Condition {
+
+        @Override
+        public Condition and(final boolean clause) {
+            if (clause) {
+                return this;
+            }
+            return new FalseCondition();
+        }
+
+        @Override
+        public Condition or(final boolean secondClause) {
+            return this;
+        }
+
+        @Override
+        public Condition then(final Runnable response) {
+            response.run();
+            return this;
+        }
+
+        @Override
+        public void otherwise(final Runnable response) {
+        }
+
+    }
+
+    /**
+     * A {@code Condition} that has evaluated to {@code false}.
+     */
+    class FalseCondition implements Condition {
+
+        @Override
+        public Condition and(final boolean clause) {
+            return this;
+        }
+
+        @Override
+        public Condition or(final boolean secondClause) {
+            if (secondClause) {
+                return new TrueCondition();
+            }
+            return this;
+        }
+
+        @Override
+        public Condition then(final Runnable response) {
+            return this;
+        }
+
+        @Override
+        public void otherwise(final Runnable response) {
+            response.run();
+        }
+
+    }
+
+}

src/main/java/net/kemitix/conditional/package-info.java

@@ -0,0 +1,22 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Paul Campbell
+ *
+ * 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.
+ */
+
+package net.kemitix.conditional;

src/test/java/net/kemitix/conditional/ConditionalTest.java

@@ -0,0 +1,153 @@
+package net.kemitix.conditional;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Paul Campbell (pcampbell@kemitix.net).
+ */
+public class ConditionalTest {
+
+    private Runnable thenResponse;
+
+    private Runnable otherwiseResponse;
+
+    private boolean thenFlag;
+
+    private boolean otherwiseFlag;
+
+    @Before
+    public void setUp() {
+        thenResponse = () -> thenFlag = true;
+        otherwiseResponse = () -> otherwiseFlag = true;
+    }
+
+    @Test
+    public void whereTrueThenRuns() {
+        //when
+        when(true);
+        //then
+        thenTheThenResponseRuns();
+    }
+
+    @Test
+    public void whereFalseOtherwiseRuns() {
+        //when
+        when(false);
+        //then
+        thenTheOtherwiseResponseRuns();
+    }
+
+    @Test
+    public void whereTrueAndTrueThenRuns() {
+        //when
+        when(true, true);
+        //then
+        thenTheThenResponseRuns();
+    }
+
+    @Test
+    public void whereTrueAndFalseThenOtherwiseRuns() {
+        //when
+        when(true, false);
+        //then
+        thenTheOtherwiseResponseRuns();
+    }
+
+    @Test
+    public void whereFalseAndTrueThenOtherwiseRuns() {
+        //when
+        when(false, true);
+        //then
+        thenTheOtherwiseResponseRuns();
+    }
+
+    @Test
+    public void whereFalseAndFalseThenOtherwiseRuns() {
+        //when
+        when(false, false);
+        //then
+        thenTheOtherwiseResponseRuns();
+    }
+
+    @Test
+    public void whereTrueThenDoSomethingAndThenDoSomethingElse() {
+        //when
+        Condition.where(true)
+                 .then(thenResponse)
+                 .and(true)
+                 .then(otherwiseResponse);
+        //then
+        thenBothResponsesRun();
+    }
+
+    @Test
+    public void whereTrueOrTrueThenDoSomething() {
+        //when
+        whenOr(true, true);
+        //then
+        thenTheThenResponseRuns();
+    }
+
+    @Test
+    public void whereTrueOrFalseThenDoSomething() {
+        //when
+        whenOr(true, false);
+        //then
+        thenTheThenResponseRuns();
+    }
+
+    @Test
+    public void whereFalseOrTrueThenDoSomething() {
+        //when
+        whenOr(false, true);
+        //then
+        thenTheThenResponseRuns();
+    }
+
+    @Test
+    public void whereFalseOrFalseThenDoSomethingElse() {
+        //when
+        whenOr(false, false);
+        //then
+        thenTheOtherwiseResponseRuns();
+    }
+
+    private void whenOr(final boolean firstClause, final boolean secondClause) {
+        Condition.where(firstClause)
+                 .or(secondClause)
+                 .then(thenResponse)
+                 .otherwise(otherwiseResponse);
+    }
+
+    private void when(final boolean clause) {
+        Condition.where(clause)
+                 .then(thenResponse)
+                 .otherwise(otherwiseResponse);
+    }
+
+    private void thenBothResponsesRun() {
+        assertThat(thenFlag).isTrue();
+        assertThat(otherwiseFlag).isTrue();
+    }
+
+    private void thenTheThenResponseRuns() {
+        assertThat(thenFlag).isTrue();
+        assertThat(otherwiseFlag).isFalse();
+    }
+
+    private void thenTheOtherwiseResponseRuns() {
+        assertThat(thenFlag).isFalse();
+        assertThat(otherwiseFlag).isTrue();
+    }
+
+    private void when(final boolean firstClause, final boolean secondClause) {
+        Condition.where(firstClause)
+                 .and(secondClause)
+                 .then(thenResponse)
+                 .otherwise(otherwiseResponse);
+    }
+
+}