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Merge pull request #4 from scijava/simplification-revised
Simplification revised
2 parents 3f8fa41 + 42ce11b commit 0119435

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‎README.md‎

Lines changed: 21 additions & 39 deletions
Original file line numberDiff line numberDiff line change
@@ -10,8 +10,8 @@ For example, `FactoryA` should take `FactoryAOptions` and
1010
expose an optional parameter "`int a`" with the same meaning and default values.
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To maintain convenience and type-safety, both `FactoryAOptions` and `FactoryBOptions` should expose
13-
a method `a(int)` to set the optional parameter. But `FactoryAOptions::a` should return an `FactoryAOptions`,
14-
and `FactoryBOptions::a` should return an `FactoryBOptions` to allow chaining more parameters of
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a method `a(int)` to set the optional parameter. But `FactoryAOptions::a` should return a `FactoryAOptions`,
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and `FactoryBOptions::a` should return a `FactoryBOptions` to allow chaining more parameters of
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`FactoryAOptions` and `FactoryBOptions` respectively, while retaining the type of the builder.
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Using scijava-optional, this can be achieved as follows:
@@ -21,26 +21,26 @@ one exposing methods to set the parameters, one exposing methods to retrieve par
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For setting:
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```java
24-
interface OptionA<T extends OptionA<T>> extends Options<T> {
24+
interface OptionA<T> extends Options<T> {
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default T a(int a) {
26-
return add("a", a);
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return setValue("a", a);
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}
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}
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```
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where the `a()` method records the parameter value (with key `"a"`) via the
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`add()` method of the `Options` super-interface.
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`setValue()` method of the `Options` super-interface.
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For getting:
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```java
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interface ValueA extends Values {
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...
37-
default int a() {}
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return value( "a", 0 );
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default int a() {
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return getValueOrDefault( "a", 0 );
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}
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}
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```
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where the `a()` method returns the parameter value (with key `"a"` and default value `0`)
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via the `value()` method of the `Values` super-interface.
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via the `getValueOrDefault()` method of the `Values` super-interface.
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Finally, the implementation of `FactoryAOptions` derives from `AbstractOptions` and all desired
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subsets of options
@@ -49,17 +49,12 @@ public class FactoryAOptions
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extends AbstractOptions< FactoryAOptions >
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implements OptionA< FactoryAOptions >, ...
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{
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static class FactoryAValues
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public class FactoryAValues
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extends AbstractValues
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implements ValueA, ...
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{
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...
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public FactoryAValues(FactoryAOptions options) {
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super( options );
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}
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}
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{}
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62-
public final FactoryAValues values = new FactoryAValues(this);;
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public final FactoryAValues values = new FactoryAValues();
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// =======================================================================
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@@ -76,49 +71,36 @@ public class FactoryAOptions
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protected FactoryAOptions copyOrThis() {
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return new FactoryAOptions(this);
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}
79-
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// =======================================================================
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// The following is not necessary, but can be overridden like this
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// to make it show up more nicely in IDE auto-complete
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@Override
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public FactoryAOptions a(int a) {
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return OptionA.super.a(a);
88-
}
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}
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```
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The parameter values are exposed through inner class `FactoryAValues` that derives from `AbstractValues`
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and all desired subsets of option values.
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The only thing that has been omitted from the above example is the parts that provide a nice `toString` implementation
95-
for the values. This is be achieved by
80+
for the values. This is be achieved by overriding the `forEach()` methods in the `Values` interfaces and
81+
implementation
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```java
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interface ValueA extends Values {
98-
default void buildToString(AbstractValues.ValuesToString sb) {
99-
sb.append("a", a());
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default void forEach(BiConsumer<String, Object> action) {
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action.accept("a", a());
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// and so on, for other parameters defined in this Values interface
10087
}
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default int a() {
103-
return value("a", 0);
90+
return getValueOrDefault("a", 0);
10491
}
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}
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```
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and
10895
```java
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static class FactoryAValues
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public class FactoryAValues
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extends AbstractValues
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implements ValueA, ...
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{
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@Override
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public String toString() {
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final ValuesToString sb = new ValuesToString();
116-
ValueA.super.buildToString(sb);
117-
return sb.toString();
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}
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120-
public FactoryAValues(FactoryAOptions options) {
121-
super(options);
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default void forEach(BiConsumer<String, Object> action) {
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ValueA.super.forEach( action );
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// and so on, for other implemented Values interfaces
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}
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}
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```

‎src/main/java/org/scijava/optional/AbstractOptions.java‎

Lines changed: 67 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -2,14 +2,15 @@
22

33
import java.util.LinkedHashMap;
44
import java.util.Map;
5+
import java.util.function.BiConsumer;
56

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public abstract class AbstractOptions< T extends AbstractOptions< T > > implements Options< T >
78
{
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final LinkedHashMap< String, Object > theOptions = new LinkedHashMap<>();
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protected AbstractOptions( T that )
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{
12-
that.theOptions.forEach( theOptions::put );
13+
theOptions.putAll( that.theOptions );
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}
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1516
public AbstractOptions()
@@ -27,14 +28,19 @@ protected T append( final T additionalOptions )
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return ( T ) this;
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2930
T concat = copyOrThis();
30-
additionalOptions.theOptions.forEach( concat.theOptions::put );
31+
additionalOptions.theOptions.forEach( ( k, v ) -> {
32+
// NB remove existing key for ordering for appended options
33+
concat.theOptions.remove( k );
34+
concat.theOptions.put( k, v );
35+
} );
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return concat;
3237
}
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3439
@Override
35-
public T add( final String key, final Object value )
40+
public T setValue( final String key, final Object value )
3641
{
3742
final T copy = copyOrThis();
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// NB remove existing key for ordering for appended options
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copy.theOptions.remove( key );
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copy.theOptions.put( key, value );
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return copy;
@@ -57,4 +63,62 @@ public String toString()
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sb.append( "}" );
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return sb.toString();
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}
66+
67+
protected abstract class AbstractValues implements Values
68+
{
69+
public void forEach( BiConsumer< String, Object > action )
70+
{
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theOptions.forEach( action );
72+
}
73+
74+
@Override
75+
public String toString()
76+
{
77+
final ValuesToString sb = new ValuesToString();
78+
forEach( sb );
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return sb.toString();
80+
}
81+
82+
@Override
83+
public < T > T getValueOrDefault( final String key, final T defaultValue )
84+
{
85+
@SuppressWarnings( "unchecked" )
86+
final T value = ( T ) theOptions.get( key );
87+
return value == null ? defaultValue : value;
88+
}
89+
}
90+
91+
protected class ValuesToString implements BiConsumer< String, Object >
92+
{
93+
private final StringBuilder sb;
94+
95+
private boolean first;
96+
97+
public ValuesToString()
98+
{
99+
sb = new StringBuilder().append( "{" );
100+
first = true;
101+
}
102+
103+
@Override
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public String toString()
105+
{
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sb.append( "}" );
107+
return sb.toString();
108+
}
109+
110+
@Override
111+
public void accept( final String key, final Object value )
112+
{
113+
if ( first )
114+
first = false;
115+
else
116+
sb.append( ", " );
117+
sb.append( key );
118+
sb.append( " = " );
119+
sb.append( value );
120+
if ( !theOptions.containsKey( key ) )
121+
sb.append( " [default]" );
122+
}
123+
}
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}

‎src/main/java/org/scijava/optional/AbstractValues.java‎

Lines changed: 0 additions & 59 deletions
This file was deleted.

‎src/main/java/org/scijava/optional/Options.java‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
package org.scijava.optional;
22

3-
public interface Options< T extends Options< T > >
3+
public interface Options< T >
44
{
5-
T add( String key, Object value );
5+
T setValue( String key, Object value );
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}

‎src/main/java/org/scijava/optional/Values.java‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,5 +2,5 @@
22

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public interface Values
44
{
5-
< T > T value( String key, T defaultValue );
5+
< T > T getValueOrDefault( String key, T defaultValue );
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}

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