Merge pull request #7 from kemitix/value-with-suppliers
Value: add where() with Supplier<T> parameters
This commit is contained in:
commit
91bb2adc0f
4 changed files with 84 additions and 2 deletions
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@ -4,6 +4,8 @@ CHANGELOG
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0.3.0
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-----
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* Add `<T> Value.where(boolean, Supplier<T>, Supplier<T>)`
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* Add `Optional<T> Value.where(boolean, Supplier<T>)`
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* Add `.travis-support`
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* Avoid danger of JVM-level deadlock during `Value` initialisation
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* Avoid danger of JVM-level deadlock during `Condition` initialisation
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10
README.adoc
10
README.adoc
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@ -201,6 +201,16 @@ if (isTrue()) {
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String result = isTrue() ? TRUE : FALSE;
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----
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[[source,java]]
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----
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final String result = Value.where(isTrue(), () -> TRUE, () -> FALSE);
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----
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[[source,java]]
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----
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final Optional<String> result = Value.where(isTrue(), () -> TRUE);
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----
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[[source,java]]
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----
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final String result = Value.<String>where(isTrue()).then(() -> TRUE)
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@ -21,6 +21,7 @@
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package net.kemitix.conditional;
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import java.util.Optional;
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import java.util.function.Supplier;
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/**
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@ -30,6 +31,41 @@ import java.util.function.Supplier;
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*/
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public interface Value {
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/**
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* Return one of two values depending on the value of a clause.
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*
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* @param clause The deciding clause
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* @param trueSupplier The supplier to provide the value when the clause is true
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* @param falseSupplier The supplier to provide the value when the clause is false
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* @param <T> The type of the value
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*
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* @return the value from either the trueSupplier or the falseSupplier
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*/
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static <T> T where(
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boolean clause,
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Supplier<T> trueSupplier,
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Supplier<T> falseSupplier
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) {
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return Value.<T>where(clause).then(trueSupplier)
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.otherwise(falseSupplier);
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}
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/**
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* Return an Optional either containing a value, if the clause is true, or empty.
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*
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* @param clause The deciding clause
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* @param trueSupplier The supplier to provide the value when the clause is true
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* @param <T> The type of the value
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*
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* @return an Optional either containing the value from the trueSupplier or empty
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*/
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static <T> Optional<T> where(
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boolean clause,
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Supplier<T> trueSupplier
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) {
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return Optional.ofNullable(Value.where(clause, trueSupplier, () -> null));
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}
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/**
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* Create a new {@link ValueClause} for the clause.
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*
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@ -3,6 +3,8 @@ package net.kemitix.conditional;
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import lombok.val;
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import org.junit.Test;
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import java.util.Optional;
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import static org.assertj.core.api.Assertions.assertThat;
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/**
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@ -15,7 +17,39 @@ public class ValueTest {
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private static final String FALSE = "false";
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@Test
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public void valueWhereTrueIsTrue() {
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public void valueWhereClauseIsTrueTypeSafe() {
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//when
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final String result = Value.where(true, () -> TRUE, () -> FALSE);
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//then
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assertThat(result).isEqualTo(TRUE);
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}
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@Test
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public void valueWhereClauseIsFalseTypeSafe() {
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//when
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final String result = Value.where(false, () -> TRUE, () -> FALSE);
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//then
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assertThat(result).isEqualTo(FALSE);
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}
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@Test
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public void valueWhereClauseIsTrueIsOptional() {
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//when
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final Optional<String> result = Value.where(true, () -> TRUE);
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//then
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assertThat(result).contains(TRUE);
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}
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@Test
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public void valueWhereClauseIsFalseIsEmptyOptional() {
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//when
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final Optional<String> result = Value.where(false, () -> TRUE);
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//then
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assertThat(result).isEmpty();
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}
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@Test
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public void valueWhereClauseIsTrue() {
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//when
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val result = Value.<String>where(true).then(() -> TRUE)
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.otherwise(() -> FALSE);
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@ -24,7 +58,7 @@ public class ValueTest {
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}
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@Test
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public void valueWhereFalseIsFalse() {
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public void valueWhereClauseIsFalse() {
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//when
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val result = Value.<String>where(false).then(() -> TRUE)
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.otherwise(() -> FALSE);
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