Condition: remove use of 'if' internaly
By using a look-up map for true and false the only branch in the code is removed.
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826dcc17ca
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1 changed files with 24 additions and 36 deletions
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@ -21,8 +21,11 @@
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package net.kemitix.conditional;
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package net.kemitix.conditional;
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import lombok.AccessLevel;
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import java.util.AbstractMap.SimpleEntry;
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import lombok.NoArgsConstructor;
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import java.util.Collections;
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import java.util.Map;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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/**
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/**
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* If-then-else in a functional-style.
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* If-then-else in a functional-style.
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@ -31,6 +34,14 @@ import lombok.NoArgsConstructor;
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*/
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*/
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public interface Condition {
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public interface Condition {
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Condition TRUE = new TrueCondition();
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Condition FALSE = new FalseCondition();
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Map<Boolean, Condition> CONDITIONS = Collections.unmodifiableMap(
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Stream.of(new SimpleEntry<>(true, TRUE), new SimpleEntry<>(false, FALSE))
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.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue)));
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/**
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/**
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* Create a new {@code Condition} for the clause.
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* Create a new {@code Condition} for the clause.
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*
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*
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@ -39,10 +50,7 @@ public interface Condition {
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* @return the Condition
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* @return the Condition
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*/
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*/
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static Condition where(final boolean clause) {
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static Condition where(final boolean clause) {
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if (clause) {
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return CONDITIONS.get(clause);
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return TrueCondition.getInstance();
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}
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return FalseCondition.getInstance();
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}
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}
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/**
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/**
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@ -52,7 +60,7 @@ public interface Condition {
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*
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*
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* @return the Condition
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* @return the Condition
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*/
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*/
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static Condition whereNot(boolean clause) {
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static Condition whereNot(final boolean clause) {
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return where(!clause);
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return where(!clause);
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}
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}
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@ -72,7 +80,7 @@ public interface Condition {
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*
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*
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* @return the Condition
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* @return the Condition
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*/
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*/
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default Condition andNot(boolean clause) {
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default Condition andNot(final boolean clause) {
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return and(!clause);
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return and(!clause);
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}
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}
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@ -92,7 +100,7 @@ public interface Condition {
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*
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*
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* @return the Condition
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* @return the Condition
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*/
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*/
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default Condition orNot(boolean clause) {
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default Condition orNot(final boolean clause) {
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return or(!clause);
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return or(!clause);
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}
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}
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@ -119,39 +127,29 @@ public interface Condition {
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*
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*
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* @return the Condition
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* @return the Condition
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*/
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*/
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default Condition otherwise(boolean clause) {
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default Condition otherwise(final boolean clause) {
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return where(clause);
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return where(clause);
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}
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}
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/**
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/**
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* A {@code Condition} that has evaluated to {@code true}.
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* A {@code Condition} that has evaluated to {@code true}.
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*/
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*/
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@NoArgsConstructor(access = AccessLevel.PRIVATE)
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class TrueCondition implements Condition {
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class TrueCondition implements Condition {
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private static final Condition INSTANCE = new TrueCondition();
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private static Condition getInstance() {
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return INSTANCE;
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}
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@Override
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@Override
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public Condition and(final boolean clause) {
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public Condition and(final boolean clause) {
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if (clause) {
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return where(clause);
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return this;
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}
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return FalseCondition.getInstance();
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}
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}
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@Override
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@Override
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public Condition or(final boolean secondClause) {
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public Condition or(final boolean secondClause) {
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return this;
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return TRUE;
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}
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}
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@Override
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@Override
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public Condition then(final Runnable response) {
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public Condition then(final Runnable response) {
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response.run();
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response.run();
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return this;
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return TRUE;
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}
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}
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@Override
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@Override
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@ -163,31 +161,21 @@ public interface Condition {
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/**
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/**
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* A {@code Condition} that has evaluated to {@code false}.
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* A {@code Condition} that has evaluated to {@code false}.
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*/
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*/
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@NoArgsConstructor(access = AccessLevel.PRIVATE)
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class FalseCondition implements Condition {
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class FalseCondition implements Condition {
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private static final Condition INSTANCE = new FalseCondition();
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private static Condition getInstance() {
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return INSTANCE;
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}
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@Override
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@Override
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public Condition and(final boolean clause) {
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public Condition and(final boolean clause) {
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return this;
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return FALSE;
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}
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}
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@Override
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@Override
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public Condition or(final boolean secondClause) {
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public Condition or(final boolean secondClause) {
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if (secondClause) {
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return where(secondClause);
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return TrueCondition.getInstance();
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}
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return this;
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}
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}
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@Override
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@Override
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public Condition then(final Runnable response) {
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public Condition then(final Runnable response) {
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return this;
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return FALSE;
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}
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}
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@Override
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@Override
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