diff --git a/balking/README.md b/balking/README.md
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+---
+layout: pattern
+title: Balking
+folder: balking
+permalink: /patterns/balking/
+categories: Concurrency
+tags:
+ - Java
+ - Difficulty-Beginner
+---
+
+## Intent
+Balking Pattern is used to prevent an object from executing certain code if it is an
+incomplete or inappropriate state
+
+
+
+## Applicability
+Use the Balking pattern when
+
+*you want to invoke an action on an object only when it is in a particular state
+*objects are generally only in a state that is prone to balking temporarily
+but for an unknown amount of time
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diff --git a/balking/etc/balking.png b/balking/etc/balking.png
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diff --git a/balking/etc/balking.ucls b/balking/etc/balking.ucls
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diff --git a/balking/etc/balking.urm.puml b/balking/etc/balking.urm.puml
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+@startuml
+package com.iluwatar.balking {
+ class App {
+ - LOGGER : Logger {static}
+ + App()
+ + main(args : String[]) {static}
+ }
+ class WashingMachine {
+ - LOGGER : Logger {static}
+ - washingMachineState : WashingMachineState
+ + WashingMachine()
+ + endOfWashing()
+ + getWashingMachineState() : WashingMachineState
+ + wash()
+ }
+ enum WashingMachineState {
+ + ENABLED {static}
+ + WASHING {static}
+ + valueOf(name : String) : WashingMachineState {static}
+ + values() : WashingMachineState[] {static}
+ }
+}
+WashingMachine --> "-washingMachineState" WashingMachineState
+@enduml
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diff --git a/balking/pom.xml b/balking/pom.xml
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+
+
+
+
+ java-design-patterns
+ com.iluwatar
+ 1.14.0-SNAPSHOT
+
+ 4.0.0
+
+ balking
+
+
+ junit
+ junit
+ test
+
+
+
+
+
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diff --git a/balking/src/main/java/com/iluwatar/balking/App.java b/balking/src/main/java/com/iluwatar/balking/App.java
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+++ b/balking/src/main/java/com/iluwatar/balking/App.java
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+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.balking;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+public class App {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+ /**
+ * @param args the command line arguments - not used
+ */
+ public static void main(String... args) {
+ final WashingMachine washingMachine = new WashingMachine();
+ ExecutorService executorService = Executors.newFixedThreadPool(3);
+ for (int i = 0; i < 3; i++) {
+ executorService.execute(washingMachine::wash);
+ }
+ executorService.shutdown();
+ try {
+ executorService.awaitTermination(10, TimeUnit.SECONDS);
+ } catch (InterruptedException ie) {
+ LOGGER.error("ERROR: Waiting on executor service shutdown!");
+ }
+ }
+
+}
diff --git a/balking/src/main/java/com/iluwatar/balking/WashingMachine.java b/balking/src/main/java/com/iluwatar/balking/WashingMachine.java
new file mode 100644
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+++ b/balking/src/main/java/com/iluwatar/balking/WashingMachine.java
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+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.balking;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class WashingMachine {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(WashingMachine.class);
+
+ private WashingMachineState washingMachineState;
+
+ public WashingMachine() {
+ washingMachineState = WashingMachineState.ENABLED;
+ }
+
+ public WashingMachineState getWashingMachineState() {
+ return washingMachineState;
+ }
+
+ /**
+ * Method responsible for washing
+ * if the object is in appropriate state
+ */
+ public void wash() {
+ synchronized (this) {
+ LOGGER.info("{}: Actual machine state: {}", Thread.currentThread().getName(), getWashingMachineState());
+ if (washingMachineState == WashingMachineState.WASHING) {
+ LOGGER.error("ERROR: Cannot wash if the machine has been already washing!");
+ return;
+ }
+ washingMachineState = WashingMachineState.WASHING;
+ }
+ LOGGER.info("{}: Doing the washing", Thread.currentThread().getName());
+ try {
+ Thread.sleep(50);
+ } catch (InterruptedException ie) {
+ ie.printStackTrace();
+ }
+ endOfWashing();
+ }
+
+ /**
+ * Method responsible of ending the washing
+ * by changing machine state
+ */
+ public synchronized void endOfWashing() {
+ washingMachineState = WashingMachineState.ENABLED;
+ LOGGER.info("{}: Washing completed.", Thread.currentThread().getId());
+ }
+
+}
diff --git a/balking/src/main/java/com/iluwatar/balking/WashingMachineState.java b/balking/src/main/java/com/iluwatar/balking/WashingMachineState.java
new file mode 100644
index 000000000..9d6cf875a
--- /dev/null
+++ b/balking/src/main/java/com/iluwatar/balking/WashingMachineState.java
@@ -0,0 +1,25 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.balking;
+
+public enum WashingMachineState {ENABLED, WASHING}
diff --git a/balking/src/test/java/com/iluwatar/balking/AppTest.java b/balking/src/test/java/com/iluwatar/balking/AppTest.java
new file mode 100644
index 000000000..8b647e1a6
--- /dev/null
+++ b/balking/src/test/java/com/iluwatar/balking/AppTest.java
@@ -0,0 +1,32 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.balking;
+
+public class AppTest {
+ @org.junit.Test
+ public void main() throws Exception {
+ String[] args = {};
+ App.main(args);
+ }
+
+}
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diff --git a/balking/src/test/java/com/iluwatar/balking/WashingMachineTest.java b/balking/src/test/java/com/iluwatar/balking/WashingMachineTest.java
new file mode 100644
index 000000000..2c7527676
--- /dev/null
+++ b/balking/src/test/java/com/iluwatar/balking/WashingMachineTest.java
@@ -0,0 +1,62 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.balking;
+
+import org.junit.Test;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.*;
+
+public class WashingMachineTest {
+
+ private volatile WashingMachineState machineStateGlobal;
+
+ @Test
+ public void wash() throws Exception {
+ WashingMachine washingMachine = new WashingMachine();
+ ExecutorService executorService = Executors.newFixedThreadPool(2);
+ executorService.execute(washingMachine::wash);
+ executorService.execute(() -> {
+ washingMachine.wash();
+ machineStateGlobal = washingMachine.getWashingMachineState();
+ });
+ executorService.shutdown();
+ try {
+ executorService.awaitTermination(10, TimeUnit.SECONDS);
+ } catch (InterruptedException ie) {
+ ie.printStackTrace();
+ }
+ assertEquals(WashingMachineState.WASHING, machineStateGlobal);
+ }
+
+ @Test
+ public void endOfWashing() throws Exception {
+ WashingMachine washingMachine = new WashingMachine();
+ washingMachine.wash();
+ assertEquals(WashingMachineState.ENABLED, washingMachine.getWashingMachineState());
+ }
+
+}
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