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samujjwaalsamujjwaal
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Added Memento and Observer
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2 files changed

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‎src/main/java/com/behavioral/memento/memento.java‎

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package com.behavioral.memento;
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import com.squareup.javapoet.*;
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import javax.lang.model.element.Modifier;
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public class memento {
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public static void main(String[] args) {
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String input1 = "Memento";
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String input2 = "Caretaker";
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String input3 = "Originator";
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String packageName = "com.BehavioralDP.memento";
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// Memento class declaration
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ClassName Memento = ClassName.get("",input1);
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FieldSpec state = FieldSpec.builder(int.class,"state")
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.addModifiers(Modifier.PRIVATE)
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.build();
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MethodSpec getstate = MethodSpec.methodBuilder("getState")
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.addModifiers(Modifier.PUBLIC)
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.returns(int.class)
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.addStatement("return $N", "state")
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.build();
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TypeSpec memento = TypeSpec.classBuilder(Memento)
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.addModifiers(Modifier.PUBLIC)
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.addJavadoc("""
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Memento stores internal state of the Originator object, protects against
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access by objects other than the Originator.""")
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.addField(state)
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.addMethod(MethodSpec.constructorBuilder()
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.addModifiers(Modifier.PUBLIC)
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.addParameter(int.class,"state")
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.addStatement("this.$N = $N",state.name,"state")
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.build())
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.addMethod(getstate)
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.build();
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JavaFile class1 = JavaFile.builder(packageName, memento)
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.skipJavaLangImports(true)
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.build();
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// Caretaker class declaration
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ClassName Caretaker = ClassName.get("",input2);
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TypeSpec caretaker = TypeSpec.classBuilder(Caretaker)
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.addModifiers(Modifier.PUBLIC)
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.addJavadoc("""
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Caretaker responsible for the Memento's safekeeping.""")
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.addField(Memento, "memento",Modifier.PRIVATE)
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.addMethod(MethodSpec.methodBuilder("getMemento")
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.addModifiers(Modifier.PUBLIC)
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.returns(Memento)
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.addStatement("return $N","memento")
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.build())
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.addMethod(MethodSpec.methodBuilder("setMemento")
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.addModifiers(Modifier.PUBLIC)
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.returns(TypeName.VOID)
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.addParameter(Memento, "memento")
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.addStatement("this.$N = memento","memento")
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.build())
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.build();
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JavaFile class2 = JavaFile.builder(packageName,caretaker)
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.skipJavaLangImports(true)
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.build();
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// Originator class declaration
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ClassName Originator = ClassName.get("",input3);
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TypeSpec originator = TypeSpec.classBuilder(Originator)
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.addModifiers(Modifier.PUBLIC)
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.addJavadoc("""
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Originator creates a Memento containing a snapshot of its current internal
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state. Originator use Memento to restore its internal state.""")
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.addField(state)
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.addMethod(MethodSpec.methodBuilder("setMemento")
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.addModifiers(Modifier.PUBLIC)
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.returns(TypeName.VOID)
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.addParameter(Memento, "memento")
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.addStatement("this.$N = $N.$N()",state.name,"memento",getstate.name)
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.build())
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.addMethod(MethodSpec.methodBuilder("createMemento")
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.addModifiers(Modifier.PUBLIC)
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.returns(Memento)
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.addStatement("return new $T(this.$N)",Memento,state.name)
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.build())
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.addMethod(getstate)
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.addMethod(MethodSpec.methodBuilder("setState")
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.addModifiers(Modifier.PUBLIC)
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.returns(TypeName.VOID)
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.addParameter(int.class, "state")
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.addStatement("this.$N = $N",state.name,"state")
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.build())
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.build();
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JavaFile class3 = JavaFile.builder(packageName,originator)
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.skipJavaLangImports(true)
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.build();
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System.out.println(class1);
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System.out.println(class2);
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System.out.println(class3);
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}
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}

‎src/main/java/com/behavioral/observer/observer.java‎

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package com.behavioral.observer;
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import com.squareup.javapoet.*;
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import javax.lang.model.element.Modifier;
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public class observer {
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public static void main(String[] args) {
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String input1 = "Observer";
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String input2 = "Subject";
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String input3 = "ConcreteSubject";
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String input4 = "ConcreteObserver";
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String packageName = "com.BehavioralDP.observer";
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// Observer interface declaration
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ClassName Observer = ClassName.get("",input1);
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MethodSpec update = MethodSpec.methodBuilder("update")
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.addModifiers(Modifier.PUBLIC,Modifier.ABSTRACT).returns(TypeName.VOID)
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.build();
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TypeSpec component = TypeSpec.interfaceBuilder(Observer)
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.addModifiers(Modifier.PUBLIC)
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.addJavadoc("Observer defines an updating interface for objects that should be notified of changes in a subject.")
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.addMethod(update)
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.build();
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JavaFile class1 = JavaFile.builder(packageName,component)
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.skipJavaLangImports(true)
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.build();
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// Subject class declaration
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ClassName Subject = ClassName.get("",input2);
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ClassName list = ClassName.get("java.util", "List");
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ClassName arrayList = ClassName.get("java.util", "ArrayList");
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ClassName Iterator = ClassName.get("java.util","Iterator");
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TypeName listOfObservers = ParameterizedTypeName.get(list,Observer);
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FieldSpec obs = FieldSpec.builder(listOfObservers,"observers",Modifier.PRIVATE)
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.initializer("new $T<$T>()",arrayList,Observer)
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.build();
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MethodSpec notifyObs = MethodSpec.methodBuilder("notifyObservers")
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.addModifiers(Modifier.PUBLIC).returns(TypeName.VOID)
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.beginControlFlow("($T iterator = $N.iterator(); iterator.hasNext();)",Iterator,obs.name)
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.addStatement("$T observer = ($T) iterator.next()",Observer,Observer)
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.addStatement("observer.$N()",update.name)
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.endControlFlow()
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.build();
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TypeSpec subject = TypeSpec.classBuilder(Subject)
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.addModifiers(Modifier.ABSTRACT)
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.addJavadoc("Subject knows its observers. Any number of Observer objects may observe a subject.")
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.addField(obs)
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.addMethod(MethodSpec.methodBuilder("attach")
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.addModifiers(Modifier.PUBLIC).returns(TypeName.VOID)
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.addParameter(Observer,"observer")
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.addStatement("$N.add(observer)",obs.name)
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.build())
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.addMethod(MethodSpec.methodBuilder("detach")
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.addModifiers(Modifier.PUBLIC).returns(TypeName.VOID)
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.addParameter(Observer,"observer")
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.addStatement("$N.remove(observer)",obs.name)
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.build())
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.addMethod(notifyObs)
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.build();
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JavaFile class2 = JavaFile.builder(packageName,subject)
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.skipJavaLangImports(true).build();
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// ConcreteSubject class declaration
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ClassName ConcreteSubject = ClassName.get("",input3);
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FieldSpec state = FieldSpec.builder(int.class,"state",Modifier.PRIVATE).build();
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MethodSpec getstate = MethodSpec.methodBuilder("getState")
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.addModifiers(Modifier.PUBLIC).returns(int.class)
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.addStatement("return $N", state.name)
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.build();
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TypeSpec concSub = TypeSpec.classBuilder(ConcreteSubject)
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.superclass(Subject)
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.addModifiers(Modifier.PUBLIC)
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.addJavadoc("""
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ConcreteSubject stores state of interest to ConcreteObserver objects, sends a notification to its observers
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when its state changes.""")
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.addField(state)
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.addMethod(getstate)
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.addMethod(MethodSpec.methodBuilder("setState")
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.addModifiers(Modifier.PUBLIC).returns(TypeName.VOID)
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.addParameter(int.class, "state")
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.addStatement("this.$N = state",state.name)
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.addStatement("this.$N()",notifyObs.name)
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.build())
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.build();
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JavaFile class3 = JavaFile.builder(packageName,concSub)
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.skipJavaLangImports(true).build();
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// ConcreteObserver class declaration
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ClassName ConcreteObserver = ClassName.get("",input4);
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FieldSpec obsState = FieldSpec.builder(int.class, "observerState",Modifier.PRIVATE).build();
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FieldSpec subjectField = FieldSpec.builder(ConcreteSubject, "subject",Modifier.PRIVATE).build();
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TypeSpec concObs = TypeSpec.classBuilder(ConcreteObserver)
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.addModifiers(Modifier.PUBLIC)
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.addSuperinterface(Observer)
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.addJavadoc("""
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ConcreteObserver maintains a reference to a ConcreteSubject object, stores
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state that should stay consistent with the subject's, implements the Observer
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updating interface to keep its state consistent with the subject's.""")
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.addField(obsState)
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.addField(subjectField)
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.addMethod(MethodSpec.constructorBuilder()
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.addModifiers(Modifier.PUBLIC)
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.addParameter(ConcreteSubject, "subject")
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.addStatement("this.$N = subject",subjectField.name)
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.build())
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.addMethod(MethodSpec.methodBuilder("update")
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.addModifiers(Modifier.PUBLIC).returns(TypeName.VOID)
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.addStatement("$N = subject.$N()",obsState.name,getstate.name)
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.build())
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.addMethod(MethodSpec.methodBuilder("getObserverState")
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.addModifiers(Modifier.PROTECTED).returns(int.class)
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.addStatement("return $N",obsState.name)
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.build())
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.build();
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JavaFile class4 = JavaFile.builder(packageName,concObs)
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.skipJavaLangImports(true).build();
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System.out.println(class1);
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System.out.println(class2);
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System.out.println(class3);
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System.out.println(class4);
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}
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}

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