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1 files changed, 391 insertions, 0 deletions

diff --git a/projects/net.wotonomy.foundation/src/main/java/net/wotonomy/foundation/NSSelector.java b/projects/net.wotonomy.foundation/src/main/java/net/wotonomy/foundation/NSSelector.java
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+++ b/projects/net.wotonomy.foundation/src/main/java/net/wotonomy/foundation/NSSelector.java
@@ -0,0 +1,391 @@
+/*
+Wotonomy: OpenStep design patterns for pure Java applications.
+Copyright (C) 2000 Blacksmith, Inc.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, see http://www.gnu.org
+*/
+
+package net.wotonomy.foundation;
+
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Comparator;
+
+import net.wotonomy.foundation.internal.PropertyComparator;
+
+/**
+* A pure java implementation of NSSelector.
+*
+* @author michael@mpowers.net
+* @author $Author: cgruber $
+* @version $Revision: 892 $
+*/
+public class NSSelector implements Comparator, Serializable
+{
+	protected NSMutableDictionary methodMap; // map of classes to methods
+	protected String methodName;
+	protected Class[] parameterTypes;
+
+	/**
+	* A marker to indicate object not found.
+	*/
+	protected static final String NOT_FOUND = "NOT_FOUND";
+	
+	/**
+	* Saves creating a new class array for parameterless method invocation.
+	*/
+	protected static final Class[] EMPTY_CLASS_ARRAY = new Class[0];
+	
+	/**
+	* Saves creating a new object array for parameterless method invocation.
+	*/
+	protected static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
+	
+    /**
+    * Constructor specifying a method name and an array of parameter types.
+    */
+    public NSSelector (String aMethodName, Class[] aParameterTypeArray)
+    {
+    	methodName = aMethodName;
+	    parameterTypes = aParameterTypeArray;
+	    methodMap = new NSMutableDictionary();
+    }
+    
+    /**
+    * Constructor specifying a method name with no parameters.
+    */
+    public NSSelector (String aMethodName)
+    {
+    	this( aMethodName, EMPTY_CLASS_ARRAY );
+    }
+    
+    /**
+    * Constructor for custom subclasses that implement specific operators
+    * and that do not use dynamic method invocation.
+    */
+    protected NSSelector()
+    {
+    }
+
+    /**
+    * Returns the name of the method.
+    */
+    public String name ()
+    {
+    	return methodName;
+    }
+
+    /**
+    * Returns the array of parameter types.
+    */
+    public Class[] parameterTypes ()
+    {
+    	return parameterTypes;
+    }
+
+    /**
+    * A String description of this selector.
+    */
+    public String toString ()
+    {
+    	StringBuffer result = new StringBuffer();
+	    result.append( "[" + getClass().getName() + ": name = " + name() + ", parameter types = [" );
+        if ( parameterTypes != null )
+        {
+            if ( parameterTypes.length > 0 )
+            {
+                result.append( parameterTypes[0].toString() );
+            }
+            for ( int i = 1; i < parameterTypes.length; i++ )
+            {
+                result.append( ", " );
+                result.append( parameterTypes[i].toString() );
+            }
+        }
+	    result.append( "] ]" );
+	    return result.toString();
+    }
+
+    /**
+    * Returns the appropriate method for the specified class.
+    */
+    public Method methodOnClass (Class aClass) 
+    	throws NoSuchMethodException
+	{
+		Object result = methodMap.objectForKey( aClass );
+		
+		if ( result == null )
+		{
+			result = getMethodForClass( aClass );
+            if ( result == null )
+            {
+                result = NOT_FOUND;
+            }
+			methodMap.setObjectForKey( result, aClass );
+		}
+		
+		if ( result == NOT_FOUND )
+		{
+			throw new NoSuchMethodException();
+		}
+		return (Method) result;
+	}
+	
+    /**
+    * Returns the appropriate method, or null if not found.
+    */
+	private Method getMethodForClass( Class aClass )
+	{
+		Method[] methods = aClass.getMethods();
+		for ( int i = 0; i < methods.length; i++ )
+		{
+			if ( methods[i].getName().equals( name() ) )
+			{
+				Class[] params = methods[i].getParameterTypes();
+				if ( params.length == parameterTypes.length )
+				{
+					boolean pass = true;
+					for ( int j = 0; j < params.length; j++ )
+					{
+						if ( ! params[j].isAssignableFrom( parameterTypes[j] ) )
+						{
+							pass = false;
+						}
+					}	
+					if ( pass ) return methods[i];
+				}
+			}
+		}
+		return null;
+	}
+
+    /**
+    * Convenience to get a method for an object.
+    */
+    public Method methodOnObject (Object anObject)
+    	throws NoSuchMethodException
+	{
+		Method m = methodOnClass( anObject.getClass() );
+        if ( m == null ) throw new NoSuchMethodException( name() );
+        return m;
+	}
+
+    /**
+    * Returns whether the class implements the method for this selector.
+    */
+    public boolean implementedByClass (Class aClass)
+    {
+    	try
+	    {
+			methodOnClass( aClass );
+			return true;
+	    }
+	    catch ( NoSuchMethodException exc )
+	    {
+	    }
+	    return false;
+    }
+
+    /**
+    * Returns whether the object's class implements the method 
+    * for this selector.
+    */
+    public boolean implementedByObject (Object anObject)
+    {
+    	try
+	    {
+			methodOnObject( anObject );
+			return true;
+	    }
+	    catch ( NoSuchMethodException exc )
+	    {
+	    }
+	    return false;
+    }
+
+    /**
+    * Invokes this selector's method on the specified object 
+    * using the specified parameters.
+    */
+    public Object invoke (Object anObject, Object[] parameters) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return methodOnObject( anObject ).invoke( anObject, parameters );
+	}
+
+    /**
+    * Invokes this selector's method on the specified object 
+    * with no parameters.
+    */
+    public Object invoke (Object anObject) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return invoke( anObject, EMPTY_OBJECT_ARRAY );
+	}
+
+    /**
+    * Invokes this selector's method on the specified object 
+    * with the specified parameter.
+    */
+    public Object invoke (Object anObject, Object aParameter) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return invoke( anObject, new Object[] { aParameter } );
+	}
+
+    /**
+    * Invokes this selector's method on the specified object 
+    * using the specified two parameters.
+    */
+    public Object invoke (Object anObject, Object p1, Object p2) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return invoke( anObject, new Object[] { p1, p2 } );
+	}
+		    
+    /**
+    * Invokes the method with the specified signature on the specified 
+    * object using the specified parameters.
+    */
+    public static Object invoke 
+		(String methodName, Class[] parameterTypes, Object anObject, Object[] parameters) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return new NSSelector( methodName, parameterTypes ).invoke( anObject, parameters );
+	}
+
+    /**
+    * Invokes the method with the specified signature on the specified object 
+    * with no parameters.
+    */
+    public static Object invoke  
+		(String methodName, Object anObject) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return NSSelector.invoke( 
+			methodName, EMPTY_CLASS_ARRAY, anObject, EMPTY_OBJECT_ARRAY );
+	}
+
+    /**
+    * Invokes the method with the specified signature on the specified 
+    * object using the specified parameter.
+    */
+    public static Object invoke  
+		(String methodName, Class[] parameterTypes, 
+		 Object anObject, Object aParameter) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return NSSelector.invoke( 
+			methodName, parameterTypes, anObject, new Object[] { aParameter } );
+	}
+
+    /**
+    * Invokes the method with the specified signature on the specified 
+    * object using the specified two parameters.
+    */
+    public static Object invoke  
+		(String methodName, Class[] parameterTypes, 
+		 Object anObject, Object p1, Object p2) 
+    	throws IllegalAccessException, IllegalArgumentException, 
+	    	InvocationTargetException, NoSuchMethodException
+	{
+		return NSSelector.invoke( 
+			methodName, parameterTypes, anObject, new Object[] { p1, p2 } );
+	}
+
+    // interface Comparator
+
+    private Comparator comparator;	
+    
+    /**
+    * Constructor specifying a method name and a comparator.
+    * This is not in the spec.
+    */
+    public NSSelector (String aMethodName, Comparator aComparator)
+    {
+    	this( aMethodName, EMPTY_CLASS_ARRAY );
+        comparator = aComparator;
+    }
+    
+    /**
+    * Returns the Comparator used for this selector.
+    * This is not in the spec.
+    */
+    public Comparator comparator()
+    {
+        if ( comparator == null )
+        {
+            comparator = new PropertyComparator( methodName );
+        }
+        return comparator;
+    }
+    
+    public int compare(Object o1, Object o2)
+    {
+        if ( comparator == null )
+        {
+            comparator = new PropertyComparator( methodName );
+        }
+        return comparator.compare( o1, o2 );
+    }
+    
+    public boolean equals(Object obj)
+    {
+        return ( obj == this );
+    }
+}
+
+/*
+ * $Log$
+ * Revision 1.1  2006/02/16 12:47:16  cgruber
+ * Check in all sources in eclipse-friendly maven-enabled packages.
+ *
+ * Revision 1.9  2003/02/12 19:34:35  mpowers
+ * Added accessor for comparator.
+ *
+ * Revision 1.8  2003/02/07 20:23:41  mpowers
+ * Provided backwards compatibility for comparators.
+ *
+ * Revision 1.7  2003/01/22 23:02:25  mpowers
+ * Fixed a null pointer error in NSSelector.toString.
+ *
+ * Revision 1.6  2003/01/18 23:46:58  mpowers
+ * EOSortOrdering is now correctly using NSSelectors.
+ *
+ * Revision 1.4  2001/10/31 15:24:45  mpowers
+ * Implicit constructor is now protected.
+ *
+ * Revision 1.3  2001/02/07 19:25:51  mpowers
+ * Fixed: method matching uses isAssignableFrom rather than ==.
+ *
+ * Revision 1.2  2001/01/08 23:30:16  mpowers
+ * Fixed major bug - selectors were not supposed to share a method map.
+ *
+ * Revision 1.1.1.1  2000/12/21 15:47:45  mpowers
+ * Contributing wotonomy.
+ *
+ * Revision 1.3  2000/12/20 16:25:39  michael
+ * Added log to all files.
+ *
+ *
+ */
+