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Improved encapsulation of the Memento pattern by moving the

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StarMementoInternal class to inner class of Star.
This commit is contained in:
Ilkka Seppala
2015-05-30 12:36:53 +03:00
parent 72bc96f81b
commit 703ebd3e20
7 changed files with 142 additions and 143 deletions
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174
memento/src/main/java/com/iluwatar/Star.java
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@ -1,69 +1,105 @@
package com.iluwatar;
/**
*
* Star uses "mementos" to store and restore state.
*
*/
public class Star {
private StarType type;
private int ageYears;
private int massTons;
public Star(StarType startType, int startAge, int startMass) {
this.type = startType;
this.ageYears = startAge;
this.massTons = startMass;
}
public void timePasses() {
ageYears *= 2;
massTons *= 8;
switch (type) {
case RED_GIANT:
type = StarType.WHITE_DWARF;
break;
case SUN:
type = StarType.RED_GIANT;
break;
case SUPERNOVA:
type = StarType.DEAD;
break;
case WHITE_DWARF:
type = StarType.SUPERNOVA;
break;
case DEAD:
ageYears *= 2;
massTons = 0;
break;
default:
break;
}
}
StarMemento getMemento() {
StarMementoInternal state = new StarMementoInternal();
state.setAgeYears(ageYears);
state.setMassTons(massTons);
state.setType(type);
return state;
}
void setMemento(StarMemento memento) {
StarMementoInternal state = (StarMementoInternal) memento;
this.type = state.getType();
this.ageYears = state.getAgeYears();
this.massTons = state.getMassTons();
}
@Override
public String toString() {
return String.format("%s age: %d years mass: %d tons", type.toString(),
ageYears, massTons);
}
}
package com.iluwatar;
/**
*
* Star uses "mementos" to store and restore state.
*
*/
public class Star {
private StarType type;
private int ageYears;
private int massTons;
public Star(StarType startType, int startAge, int startMass) {
this.type = startType;
this.ageYears = startAge;
this.massTons = startMass;
}
public void timePasses() {
ageYears *= 2;
massTons *= 8;
switch (type) {
case RED_GIANT:
type = StarType.WHITE_DWARF;
break;
case SUN:
type = StarType.RED_GIANT;
break;
case SUPERNOVA:
type = StarType.DEAD;
break;
case WHITE_DWARF:
type = StarType.SUPERNOVA;
break;
case DEAD:
ageYears *= 2;
massTons = 0;
break;
default:
break;
}
}
StarMemento getMemento() {
StarMementoInternal state = new StarMementoInternal();
state.setAgeYears(ageYears);
state.setMassTons(massTons);
state.setType(type);
return state;
}
void setMemento(StarMemento memento) {
StarMementoInternal state = (StarMementoInternal) memento;
this.type = state.getType();
this.ageYears = state.getAgeYears();
this.massTons = state.getMassTons();
}
@Override
public String toString() {
return String.format("%s age: %d years mass: %d tons", type.toString(),
ageYears, massTons);
}
/**
*
* StarMemento implementation
*
*/
private static class StarMementoInternal implements StarMemento {
private StarType type;
private int ageYears;
private int massTons;
public StarType getType() {
return type;
}
public void setType(StarType type) {
this.type = type;
}
public int getAgeYears() {
return ageYears;
}
public void setAgeYears(int ageYears) {
this.ageYears = ageYears;
}
public int getMassTons() {
return massTons;
}
public void setMassTons(int massTons) {
this.massTons = massTons;
}
}
}

37
memento/src/main/java/com/iluwatar/StarMementoInternal.java
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@ -1,37 +0,0 @@
package com.iluwatar;
/**
*
* Internal interface to memento.
*
*/
public class StarMementoInternal implements StarMemento {
private StarType type;
private int ageYears;
private int massTons;
public StarType getType() {
return type;
}
public void setType(StarType type) {
this.type = type;
}
public int getAgeYears() {
return ageYears;
}
public void setAgeYears(int ageYears) {
this.ageYears = ageYears;
}
public int getMassTons() {
return massTons;
}
public void setMassTons(int massTons) {
this.massTons = massTons;
}
}