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task: Explanations and grammar fixes for all the GoF patterns (#1791)

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* Grammatical fixes to command pattern

* Update bridge pattern readme

* Fixes to builder pattern grammar

* Update chain of responsibility

* Improvements to the composite example

* Fixes to headings

* Minor updates to decorator pattern

* Update facade

* Update factory example

* Update factory method

* Update flyweight

* Interpreter explanation

* Update iterator readme

* Add explanation for mediator pattern

* Grammatical fixes to memento

* Grammar fixes for observer

* Update explanation for the prototype pattern

* Proxy pattern grammar fixes

* Update singleton

* Grammar fixes to state pattern

* Grammar fixes for strategy

* Grammar fixes, template method

* Grammar fixes for visitor

* Fix typo
This commit is contained in:
Ilkka Seppälä
2021-06-24 15:57:20 +03:00
committed by GitHub
parent bbdff14a66
commit 04bf566dc1
66 changed files with 872 additions and 357 deletions
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51
chain-of-responsibility/src/main/java/com/iluwatar/chain/App.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
/**
* The Chain of Responsibility pattern is a design pattern consisting of command objects and a
* series of processing objects. Each processing object contains logic that defines the types of
* command objects that it can handle; the rest are passed to the next processing object in the
* chain. A mechanism also exists for adding new processing objects to the end of this chain.
*
* <p>In this example we organize the request handlers ({@link RequestHandler}) into a chain where
* each handler has a chance to act on the request on its turn. Here the king ({@link OrcKing})
* makes requests and the military orcs ({@link OrcCommander}, {@link OrcOfficer}, {@link
* OrcSoldier}) form the handler chain.
*/
public class App {
/**
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {
var king = new OrcKing();
king.makeRequest(new Request(RequestType.DEFEND_CASTLE, "defend castle"));
king.makeRequest(new Request(RequestType.TORTURE_PRISONER, "torture prisoner"));
king.makeRequest(new Request(RequestType.COLLECT_TAX, "collect tax"));
}
}

49
chain-of-responsibility/src/main/java/com/iluwatar/chain/OrcCommander.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
/**
* OrcCommander.
*/
public class OrcCommander extends RequestHandler {
public OrcCommander(RequestHandler handler) {
super(handler);
}
@Override
public void handleRequest(Request req) {
if (RequestType.DEFEND_CASTLE == req.getRequestType()) {
printHandling(req);
req.markHandled();
} else {
super.handleRequest(req);
}
}
@Override
public String toString() {
return "Orc commander";
}
}

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chain-of-responsibility/src/main/java/com/iluwatar/chain/OrcKing.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
/**
* OrcKing makes requests that are handled by the chain.
*/
public class OrcKing {
private RequestHandler chain;
public OrcKing() {
buildChain();
}
private void buildChain() {
chain = new OrcCommander(new OrcOfficer(new OrcSoldier(null)));
}
public void makeRequest(Request req) {
chain.handleRequest(req);
}
}

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chain-of-responsibility/src/main/java/com/iluwatar/chain/OrcOfficer.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
/**
* OrcOfficer.
*/
public class OrcOfficer extends RequestHandler {
public OrcOfficer(RequestHandler handler) {
super(handler);
}
@Override
public void handleRequest(Request req) {
if (RequestType.TORTURE_PRISONER == req.getRequestType()) {
printHandling(req);
req.markHandled();
} else {
super.handleRequest(req);
}
}
@Override
public String toString() {
return "Orc officer";
}
}

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chain-of-responsibility/src/main/java/com/iluwatar/chain/OrcSoldier.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
/**
* OrcSoldier.
*/
public class OrcSoldier extends RequestHandler {
public OrcSoldier(RequestHandler handler) {
super(handler);
}
@Override
public void handleRequest(Request req) {
if (RequestType.COLLECT_TAX == req.getRequestType()) {
printHandling(req);
req.markHandled();
} else {
super.handleRequest(req);
}
}
@Override
public String toString() {
return "Orc soldier";
}
}

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chain-of-responsibility/src/main/java/com/iluwatar/chain/Request.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
import java.util.Objects;
/**
* Request.
*/
public class Request {
/**
* The type of this request, used by each item in the chain to see if they should or can handle
* this particular request.
*/
private final RequestType requestType;
/**
* A description of the request.
*/
private final String requestDescription;
/**
* Indicates if the request is handled or not. A request can only switch state from unhandled to
* handled, there's no way to 'unhandle' a request.
*/
private boolean handled;
/**
* Create a new request of the given type and accompanied description.
*
* @param requestType The type of request
* @param requestDescription The description of the request
*/
public Request(final RequestType requestType, final String requestDescription) {
this.requestType = Objects.requireNonNull(requestType);
this.requestDescription = Objects.requireNonNull(requestDescription);
}
/**
* Get a description of the request.
*
* @return A human readable description of the request
*/
public String getRequestDescription() {
return requestDescription;
}
/**
* Get the type of this request, used by each person in the chain of command to see if they should
* or can handle this particular request.
*
* @return The request type
*/
public RequestType getRequestType() {
return requestType;
}
/**
* Mark the request as handled.
*/
public void markHandled() {
this.handled = true;
}
/**
* Indicates if this request is handled or not.
*
* @return <tt>true</tt> when the request is handled, <tt>false</tt> if not
*/
public boolean isHandled() {
return this.handled;
}
@Override
public String toString() {
return getRequestDescription();
}
}

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chain-of-responsibility/src/main/java/com/iluwatar/chain/RequestHandler.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
/**
* RequestHandler.
*/
@Slf4j
@AllArgsConstructor
public abstract class RequestHandler {
private final RequestHandler next;
/**
* Request handler.
*/
public void handleRequest(Request req) {
if (next != null) {
next.handleRequest(req);
}
}
protected void printHandling(Request req) {
LOGGER.info("{} handling request \"{}\"", this, req);
}
@Override
public abstract String toString();
}

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chain-of-responsibility/src/main/java/com/iluwatar/chain/RequestType.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
/**
* RequestType enumeration.
*/
public enum RequestType {
DEFEND_CASTLE,
TORTURE_PRISONER,
COLLECT_TAX
}

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chain-of-responsibility/src/test/java/com/iluwatar/chain/AppTest.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
/**
* Application test
*/
class AppTest {
/**
* Issue: Add at least one assertion to this test case.
*
* Solution: Inserted assertion to check whether the execution of the main method in {@link App}
* throws an exception.
*/
@Test
void shouldExecuteApplicationWithoutException() {
assertDoesNotThrow(() -> App.main(new String[]{}));
}
}

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chain-of-responsibility/src/test/java/com/iluwatar/chain/OrcKingTest.java Normal file
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/*
* The MIT License
* Copyright © 2014-2021 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.chain;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.List;
import org.junit.jupiter.api.Test;
/**
* Date: 12/6/15 - 9:29 PM
*
* @author Jeroen Meulemeester
*/
class OrcKingTest {
/**
* All possible requests
*/
private static final List<Request> REQUESTS = List.of(
new Request(RequestType.DEFEND_CASTLE, "Don't let the barbarians enter my castle!!"),
new Request(RequestType.TORTURE_PRISONER, "Don't just stand there, tickle him!"),
new Request(RequestType.COLLECT_TAX, "Don't steal, the King hates competition ...")
);
@Test
void testMakeRequest() {
final var king = new OrcKing();
REQUESTS.forEach(request -> {
king.makeRequest(request);
assertTrue(
request.isHandled(),
"Expected all requests from King to be handled, but [" + request + "] was not!"
);
});
}
}