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Zhen Li
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Add Value#asXXX(defalutValue) for primary types
Add Value#computeOrDefault(Function<Value, T> mapper, T defaultValue) for other types Add Value#computeOrNull(Function<Value, T> mapper) for shortcuts to call Value#computeOrDefault(Function<Value, T> mapper, T defaultValue=null)
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‎driver/src/main/java/org/neo4j/driver/internal/value/ValueAdapter.java

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@@ -90,6 +90,42 @@ public String asString()
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throw new Uncoercible( type().name(), "Java String" );
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}
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@Override
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public boolean asBoolean( boolean defaultValue )
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{
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return computeOrDefault( Value:: asBoolean, defaultValue );
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}
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@Override
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public String asString( String defaultValue )
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{
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return computeOrDefault( (Value::asString), defaultValue );
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}
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@Override
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public long asLong( long defaultValue )
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{
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return computeOrDefault( Value::asLong, defaultValue );
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}
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@Override
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public int asInt( int defaultValue )
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{
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return computeOrDefault( Value::asInt, defaultValue );
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}
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@Override
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public double asDouble( double defaultValue )
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{
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return computeOrDefault( Value::asDouble, defaultValue );
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}
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@Override
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public float asFloat( float defaultValue )
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{
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return computeOrDefault( Value::asFloat, defaultValue );
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}
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@Override
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public long asLong()
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{
@@ -150,6 +186,22 @@ public Object asObject()
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throw new Uncoercible( type().name(), "Java Object" );
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}
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@Override
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public <T> T computeOrDefault( Function<Value,T> mapper, T defaultValue )
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{
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if ( isNull() )
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{
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return defaultValue;
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}
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return mapper.apply( this );
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}
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@Override
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public <T> T computeOrNull( Function<Value,T> mapper )
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{
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return computeOrDefault( mapper, null );
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}
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@Override
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public byte[] asByteArray()
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{

‎driver/src/main/java/org/neo4j/driver/v1/Value.java

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@@ -26,6 +26,7 @@
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import java.util.List;
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import java.util.Map;
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import org.neo4j.driver.internal.value.NullValue;
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import org.neo4j.driver.v1.exceptions.ClientException;
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import org.neo4j.driver.v1.exceptions.value.LossyCoercion;
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import org.neo4j.driver.v1.exceptions.value.Uncoercible;
@@ -194,12 +195,36 @@ public interface Value extends MapAccessor, MapAccessorWithDefaultValue
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*/
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Object asObject();
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/**
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* Apply the mapping function on the value if the value is not a {@link NullValue}, or the default value if the value is a {@link NullValue}.
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* @param mapper The mapping function defines how to map a {@link Value} to T.
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* @param defaultValue the value to return if the value is a {@link NullValue}
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* @param <T> The return type
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* @return The value after applying the given mapping function or the default value if the value is {@link NullValue}.
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*/
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<T>T computeOrDefault( Function<Value, T> mapper, T defaultValue );
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/**
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* Apply the mapping function on the value if the value is not a {@link NullValue}, or null if the value is a {@link NullValue}.
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* @param mapper The mapping function defines how to map a {@link Value} to T.
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* @param <T> The return type
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* @return The value after applying the given mapping function or null if the value is {@link NullValue}.
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*/
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<T>T computeOrNull( Function<Value, T> mapper );
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/**
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* @return the value as a Java boolean, if possible.
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* @throws Uncoercible if value types are incompatible.
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*/
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boolean asBoolean();
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/**
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* @param defaultValue return this value if the value is a {@link NullValue}.
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* @return the value as a Java boolean, if possible.
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* @throws Uncoercible if value types are incompatible.
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*/
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boolean asBoolean( boolean defaultValue );
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/**
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* @return the value as a Java byte array, if possible.
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* @throws Uncoercible if value types are incompatible.
@@ -212,6 +237,12 @@ public interface Value extends MapAccessor, MapAccessorWithDefaultValue
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*/
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String asString();
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/**
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* @param defaultValue return this value if the value is null.
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* @return the value as a Java String, if possible
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*/
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String asString( String defaultValue );
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/**
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* @return the value as a Java Number, if possible.
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* @throws Uncoercible if value types are incompatible.
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*/
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long asLong();
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/**
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* Returns a Java long if no precision is lost in the conversion.
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* @param defaultValue return this default value if the value is a {@link NullValue}.
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* @return the value as a Java long.
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* @throws LossyCoercion if it is not possible to convert the value without loosing precision.
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* @throws Uncoercible if value types are incompatible.
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*/
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long asLong( long defaultValue );
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/**
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* Returns a Java int if no precision is lost in the conversion.
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*
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*/
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int asInt();
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/**
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* Returns a Java int if no precision is lost in the conversion.
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* @param defaultValue return this default value if the value is a {@link NullValue}.
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* @return the value as a Java int.
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* @throws LossyCoercion if it is not possible to convert the value without loosing precision.
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* @throws Uncoercible if value types are incompatible.
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*/
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int asInt( int defaultValue );
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/**
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* Returns a Java double if no precision is lost in the conversion.
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*
@@ -245,6 +294,16 @@ public interface Value extends MapAccessor, MapAccessorWithDefaultValue
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*/
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double asDouble();
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/**
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* Returns a Java double if no precision is lost in the conversion.
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* @param defaultValue default to this value if the value is a {@link NullValue}.
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* @return the value as a Java double.
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* @throws LossyCoercion if it is not possible to convert the value without loosing precision.
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* @throws Uncoercible if value types are incompatible.
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*/
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double asDouble( double defaultValue );
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/**
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* Returns a Java float if no precision is lost in the conversion.
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*
@@ -254,6 +313,16 @@ public interface Value extends MapAccessor, MapAccessorWithDefaultValue
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*/
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float asFloat();
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/**
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* Returns a Java float if no precision is lost in the conversion.
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* @param defaultValue default to this value if the value is a {@link NullValue}
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* @return the value as a Java float.
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* @throws LossyCoercion if it is not possible to convert the value without loosing precision.
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* @throws Uncoercible if value types are incompatible.
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*/
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float asFloat( float defaultValue );
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/**
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* If the underlying type can be viewed as a list, returns a java list of
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* values, where each value has been converted using {@link #asObject()}.

‎driver/src/test/java/org/neo4j/driver/internal/value/NullValueTest.java

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@@ -20,11 +20,23 @@
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import org.junit.Test;
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import java.time.LocalDate;
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import java.time.LocalDateTime;
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import java.time.LocalTime;
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import java.time.OffsetTime;
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import java.time.ZonedDateTime;
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import java.util.Collections;
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import org.neo4j.driver.internal.types.TypeConstructor;
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import org.neo4j.driver.v1.Value;
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import org.neo4j.driver.v1.Values;
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import org.neo4j.driver.v1.util.Function;
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import static org.hamcrest.MatcherAssert.assertThat;
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import static org.hamcrest.Matchers.equalTo;
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import static org.hamcrest.Matchers.nullValue;
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import static org.junit.Assert.assertTrue;
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import static org.neo4j.driver.v1.Values.point;
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public class NullValueTest
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{
@@ -45,4 +57,78 @@ public void shouldTypeAsNull()
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{
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assertThat( ((InternalValue) NullValue.NULL).typeConstructor(), equalTo( TypeConstructor.NULL ) );
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}
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@Test
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public void shouldReturnNativeTypesAsDefaultValue() throws Throwable
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{
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Value value = NullValue.NULL;
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assertThat( value.asBoolean( false ), equalTo( false ) );
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assertThat( value.asBoolean( true ), equalTo( true ) );
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assertThat( value.asString( "string value" ), equalTo( "string value" ) );
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assertThat( value.asInt( 10 ), equalTo( 10 ) );
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assertThat( value.asLong( 100L ), equalTo( 100L ) );
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assertThat( value.asFloat( 10.4f ), equalTo( 10.4f ) );
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assertThat( value.asDouble( 10.10 ), equalTo( 10.10 ) );
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}
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@Test
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public void shouldReturnAsNull() throws Throwable
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{
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Value value = NullValue.NULL;
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assertThat( value.computeOrNull( Value::asObject ), nullValue() );
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assertThat( value.computeOrNull( Value::asNumber ), nullValue() );
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assertThat( value.computeOrNull( Value::asByteArray ), nullValue() );
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assertThat( value.computeOrNull( Value::asEntity ), nullValue() );
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assertThat( value.computeOrNull( Value::asNode ), nullValue() );
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assertThat( value.computeOrNull( Value::asRelationship ), nullValue() );
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assertThat( value.computeOrNull( Value::asPath ), nullValue() );
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assertThat( value.computeOrNull( Value::asPoint ), nullValue() );
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assertThat( value.computeOrNull( Value::asLocalDate ), nullValue() );
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assertThat( value.computeOrNull( Value::asOffsetTime ), nullValue() );
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assertThat( value.computeOrNull( Value::asLocalTime ), nullValue() );
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assertThat( value.computeOrNull( Value::asLocalDateTime ), nullValue() );
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assertThat( value.computeOrNull( Value::asZonedDateTime ), nullValue() );
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assertThat( value.computeOrNull( Value::asIsoDuration ), nullValue() );
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assertThat( value.computeOrNull( Value::asList ), nullValue() );
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assertThat( value.computeOrNull( Value::asMap ), nullValue() );
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}
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@Test
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public void shouldReturnAsDefaultValue() throws Throwable
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{
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Value value = NullValue.NULL;
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assertThat( value.computeOrDefault( Value::asObject, "null" ), equalTo( "null" ) );
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assertThat( value.computeOrDefault( Value::asNumber, 10 ), equalTo( 10 ) );
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assertThat( value.computeOrDefault( Value::asByteArray, new byte[0] ), equalTo( new byte[0] ) );
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assertThat( value.computeOrDefault( Value::asEntity, null ), nullValue() );
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assertThat( value.computeOrDefault( Value::asNode, null ), nullValue() );
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assertThat( value.computeOrDefault( Value::asRelationship, null ), nullValue() );
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assertThat( value.computeOrDefault( Value::asPath, null ), nullValue() );
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assertComputeOrDefaultReturnsDefaultValue( Value::asPoint, point( 1234, 1, 2 ) );
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assertComputeOrDefaultReturnsDefaultValue( Value::asLocalDate, LocalDate.now() );
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assertComputeOrDefaultReturnsDefaultValue( Value::asOffsetTime, OffsetTime.now() );
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assertComputeOrDefaultReturnsDefaultValue( Value::asLocalTime, LocalTime.now() );
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assertComputeOrDefaultReturnsDefaultValue( Value::asLocalDateTime, LocalDateTime.now() );
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assertComputeOrDefaultReturnsDefaultValue( Value::asZonedDateTime, ZonedDateTime.now() );
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assertComputeOrDefaultReturnsDefaultValue( Value::asIsoDuration, Values.isoDuration( 1, 2, 3, 4 ) );
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assertThat( value.computeOrDefault( Value::asList, Collections.emptyList() ), equalTo( Collections.emptyList() ) );
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assertThat( value.computeOrDefault( Value::asMap, Collections.emptyMap() ), equalTo( Collections.emptyMap() ) );
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}
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private <T> void assertComputeOrDefaultReturnsDefaultValue( Function<Value, T> f, T defaultAndExpectedValue )
129+
{
130+
Value value = NullValue.NULL;
131+
T returned = value.computeOrDefault( f, defaultAndExpectedValue );
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assertThat( returned, equalTo( defaultAndExpectedValue ) );
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}
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}

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