Options helper classes

Author: tpietzsch

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

@@ -0,0 +1,57 @@
+package org.scijava.optional;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public abstract class AbstractOptions< T extends AbstractOptions< T > > implements Options< T >
+{
+	final LinkedHashMap< String, Object > theOptions = new LinkedHashMap<>();
+
+	protected AbstractOptions( T that )
+	{
+		that.theOptions.forEach( theOptions::put );
+	}
+
+	public AbstractOptions()
+	{
+	}
+
+	protected T copyOrThis()
+	{
+		return ( T ) this;
+	}
+
+	protected T append( final T additionalOptions )
+	{
+		T concat = copyOrThis();
+		additionalOptions.theOptions.forEach( concat.theOptions::put );
+		return concat;
+	}
+
+	@Override
+	public T add( final String key, final Object value )
+	{
+		final T copy = copyOrThis();
+		copy.theOptions.remove( key );
+		copy.theOptions.put( key, value );
+		return copy;
+	}
+
+	@Override
+	public String toString()
+	{
+		final StringBuilder sb = new StringBuilder();
+		sb.append( "{" );
+		int numLeft = theOptions.size();
+		for ( Map.Entry< String, Object > option : theOptions.entrySet() )
+		{
+			sb.append( option.getKey() );
+			sb.append( " = " );
+			sb.append( option.getValue() );
+			if ( --numLeft > 0 )
+				sb.append( ", " );
+		}
+		sb.append( "}" );
+		return sb.toString();
+	}
+}

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

@@ -0,0 +1,59 @@
+package org.scijava.optional;
+
+import java.util.LinkedHashMap;
+
+public abstract class AbstractValues implements Values
+{
+	private final LinkedHashMap< String, Object > theOptions;
+
+	public AbstractValues( AbstractOptions< ? > options )
+	{
+		this.theOptions = options.theOptions;
+	}
+
+	public void buildToString( final ValuesToString sb )
+	{
+		throw new UnsupportedOperationException( "internal, not supposed to be called" );
+	}
+
+	@Override
+	public < T > T value( final String key, final T defaultValue )
+	{
+		@SuppressWarnings( "unchecked" )
+		final T value = ( T ) theOptions.get( key );
+		return value == null ? defaultValue : value;
+	}
+
+	public class ValuesToString
+	{
+		private final StringBuilder sb;
+
+		private boolean first;
+
+		public ValuesToString()
+		{
+			sb = new StringBuilder().append( "{" );
+			first = true;
+		}
+
+		public < T > void append( final String key, final T value )
+		{
+			if ( first )
+				first = false;
+			else
+				sb.append( ", " );
+			sb.append( key );
+			sb.append( " = " );
+			sb.append( value );
+			if ( !theOptions.containsKey( key ) )
+				sb.append( " [default]" );
+		}
+
+		@Override
+		public String toString()
+		{
+			sb.append( "}" );
+			return sb.toString();
+		}
+	}
+}

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

@@ -0,0 +1,6 @@
+package org.scijava.optional;
+
+public interface Options< T extends Options< T > >
+{
+	T add( String key, Object value );
+}

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

@@ -0,0 +1,6 @@
+package org.scijava.optional;
+
+public interface Values
+{
+	< T > T value( String key, T defaultValue );
+}