core/java12/com/vladium/util/IProperties.java - platform/external/emma - Git at Google

 /* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved.
  *
  * This program and the accompanying materials are made available under
  * the terms of the Common Public License v1.0 which accompanies this distribution,
  * and is available at http://www.eclipse.org/legal/cpl-v10.html
  *
  * $Id: IProperties.java,v 1.1.1.1.2.1 2004/07/08 10:52:10 vlad_r Exp $
  */
 package com.vladium.util;

 import java.io.PrintStream;
 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Properties;
 import java.util.Set;
 import java.util.TreeSet;

 // ----------------------------------------------------------------------------
 /**
  * @author Vlad Roubtsov, (C) 2003
  */
 public
 interface IProperties
 {
     // public: ................................................................

     /**
      * An IMapper is a stateless hook for mapping a arbitrary property key
      * to another (useful, for example, for property aliasing and defaulting).
      * Each IMapper must be completely stateless and could be shared between
      * multiple IProperties instances (and invoked from multiple concurrent threads).
      */
     interface IMapper
     {
         String getMappedKey (final String key);

     } // end of nested interface


     String getProperty (String key);
     String getProperty (String key, String dflt);
     boolean isOverridden (String key);

     IProperties copy ();
     Iterator /* String */ properties ();
     Properties toProperties ();
     /**
      * @param prefix [may not be null]
      */
     String [] toAppArgsForm (final String prefix);
     boolean isEmpty ();
     void list (PrintStream out);
     void list (PrintWriter out);

     String setProperty (String key, String value);


     abstract class Factory
     {
         /**
          * Creates an empty IProperties set with an optional property mapper.
          *
          * @param mapper [may be null]
          * @return an empty property set [never null]
          */
         public static IProperties create (final IMapper mapper)
         {
             return new PropertiesImpl (null, mapper);
         }

         /**
          * Converts a java.util.Properties instance to an IProperties instance,
          * with an optional property mapper. Note that 'properties' content is
          * shallowly cloned, so the result can be mutated independently from
          * the input.
          *
          * @param properties [may not be null]
          * @param mapper [may be null]
          * @return a property set based on 'properties' [never null]
          */
         public static IProperties wrap (final Properties properties, final IMapper mapper)
         {
             final HashMap map = new HashMap ();

             // always use propertyNames() for traversing java.util.Properties:

             for (Enumeration names = properties.propertyNames (); names.hasMoreElements (); )
             {
                 final String n = (String) names.nextElement ();
                 final String v = properties.getProperty (n);

                 map.put (n, v);
             }

             return new PropertiesImpl (map, mapper); // note: map is a defensive clone
         }

         /**
          * Combines two property sets by creating a property set that chains 'overrides'
          * to 'base' for property delegation. Note that 'overrides' are cloned
          * defensively and so the result can be mutated independently of both inputs.
          *
          * @param overrides [may be null]
          * @param base [may be null]
          * @return [never null; an empty property set with a null mapper is created
          * if both inputs are null]
          */
         public static IProperties combine (final IProperties overrides, final IProperties base)
         {
             final IProperties result = overrides != null
                 ? overrides.copy ()
                 : create (null);

             // [assertion: result != null]

             ((PropertiesImpl) result).getLastProperties ().setDelegate ((PropertiesImpl) base);

             return result;
         }

         /*
          * Not MT-safe
          */
         private static final class PropertiesImpl implements IProperties, Cloneable
         {
             // ACCESSORS (IProperties):

             public String getProperty (final String key)
             {
                 return getProperty (key, null);
             }

             public String getProperty (final String key, final String dflt)
             {
                 String value = (String) m_valueMap.get (key);

                 // first, try to delegate horizontally:
                 if ((value == null) && (m_mapper != null))
                 {
                     final String mappedKey = m_mapper.getMappedKey (key);

                     if (mappedKey != null)
                         value = (String) m_valueMap.get (mappedKey);
                 }

                 // next, try to delegate vertically:
                 if ((value == null) && (m_delegate != null))
                 {
                     value = m_delegate.getProperty (key, null);
                 }

                 return value != null ? value : dflt;
             }

             public boolean isOverridden (final String key)
             {
                 return m_valueMap.containsKey (key);
             }

             public IProperties copy ()
             {
                 final PropertiesImpl _clone;
                 try
                 {
                     _clone = (PropertiesImpl) super.clone ();
                 }
                 catch (CloneNotSupportedException cnse)
                 {
                     throw new Error (cnse.toString ()); // never happens
                 }

                 _clone.m_valueMap = (HashMap) m_valueMap.clone ();
                 _clone.m_unmappedKeySet = null;

                 // note: m_mapper field is not cloned by design (mappers are stateless/shareable)

                 PropertiesImpl scan = _clone;
                 for (PropertiesImpl delegate = m_delegate; delegate != null; delegate = delegate.m_delegate)
                 {
                     final PropertiesImpl _delegateClone;
                     try
                     {
                         _delegateClone = (PropertiesImpl) delegate.clone ();
                     }
                     catch (CloneNotSupportedException cnse)
                     {
                         throw new Error (cnse.toString ()); // never happens
                     }

                     // note that the value map needs to be cloned not only for the
                     // outermost IProperties set but for the inner ones as well
                     // (to prevent independent mutation in them from showing through)

                     _delegateClone.m_valueMap = (HashMap) delegate.m_valueMap.clone ();
                     _delegateClone.m_unmappedKeySet = null; // ensure that the last delegate will have this field reset

                     scan.setDelegate (_delegateClone);
                     scan = _delegateClone;
                 }

                 return _clone;
             }

             public Iterator /* String */ properties ()
             {
                 return unmappedKeySet ().iterator ();
             }

             public Properties toProperties ()
             {
                 final Properties result = new Properties ();

                 for (Iterator i = properties (); i.hasNext (); )
                 {
                     final String n = (String) i.next ();
                     final String v = getProperty (n);

                     result.setProperty (n, v);
                 }

                 return result;
             }

             public boolean isEmpty ()
             {
                 return m_valueMap.isEmpty () && ((m_delegate == null) || ((m_delegate != null) && m_delegate.isEmpty ()));
             }

             public String [] toAppArgsForm (final String prefix)
             {
                 if (isEmpty ())
                     return IConstants.EMPTY_STRING_ARRAY;
                 else
                 {
                     if (prefix == null)
                         throw new IllegalArgumentException ("null input: prefix");

                     final List _result = new ArrayList ();
                     for (Iterator names = properties (); names.hasNext (); )
                     {
                         final String name = (String) names.next ();
                         final String value = getProperty (name, "");

                         _result.add (prefix.concat (name).concat ("=").concat (value));
                     }

                     final String [] result = new String [_result.size ()];
                     _result.toArray (result);

                     return result;
                 }
             }

             public void list (final PrintStream out)
             {
                 if (out != null)
                 {
                     for (Iterator i = properties (); i.hasNext (); )
                     {
                         final String n = (String) i.next ();
                         final String v = getProperty (n);

                         out.println (n + ":\t[" + v + "]");
                     }
                 }
             }

             public void list (final PrintWriter out)
             {
                 if (out != null)
                 {
                     for (Iterator i = properties (); i.hasNext (); )
                     {
                         final String n = (String) i.next ();
                         final String v = getProperty (n);

                         out.println (n + ":\t[" + v + "]");
                     }
                 }
             }

             // MUTATORS:

             public String setProperty (final String key, final String value)
             {
                 if (value == null)
                     throw new IllegalArgumentException ("null input: value");

                 m_unmappedKeySet = null;

                 return (String) m_valueMap.put (key, value);
             }


             PropertiesImpl (final HashMap values, final IMapper mapper)
             {
                 m_mapper = mapper;
                 m_valueMap = values != null ? values : new HashMap ();

                 m_delegate = null;
             }


             Set unmappedKeySet ()
             {
                 Set result = m_unmappedKeySet;
                 if (result == null)
                 {
                     result = new TreeSet ();
                     result.addAll (m_valueMap.keySet ());
                     if (m_delegate != null)
                         result.addAll (m_delegate.unmappedKeySet ());

                     m_unmappedKeySet = result;
                     return result;
                 }

                 return result;
             }

             // ACCESSORS:

             PropertiesImpl getLastProperties ()
             {
                 PropertiesImpl result = this;

                 for (PropertiesImpl delegate = m_delegate; delegate != null; delegate = delegate.m_delegate)
                 {
                     // this does not detect all possible cycles:
                     if (delegate == this)
                         throw new IllegalStateException ("cyclic delegation detected");

                     result = delegate;
                 }

                 return result;
             }

             // MUTATORS:

             void setDelegate (final PropertiesImpl delegate)
             {
                 m_delegate = delegate;

                 m_unmappedKeySet = null;
             }


             private final IMapper m_mapper;
             private /*final*/ HashMap m_valueMap; // never null

             private PropertiesImpl m_delegate;
             private transient Set m_unmappedKeySet;

         } // end of nested class

     } // end of nested class

     // protected: .............................................................

     // package: ...............................................................

     // private: ...............................................................

 } // end of class
 // ----------------------------------------------------------------------------
	/* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved.
	*
	* This program and the accompanying materials are made available under
	* the terms of the Common Public License v1.0 which accompanies this distribution,
	* and is available at http://www.eclipse.org/legal/cpl-v10.html
	*
	* $Id: IProperties.java,v 1.1.1.1.2.1 2004/07/08 10:52:10 vlad_r Exp $
	*/
	package com.vladium.util;

	import java.io.PrintStream;
	import java.io.PrintWriter;
	import java.util.ArrayList;
	import java.util.Enumeration;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Properties;
	import java.util.Set;
	import java.util.TreeSet;

	// ----------------------------------------------------------------------------
	/**
	* @author Vlad Roubtsov, (C) 2003
	*/
	public
	interface IProperties
	{
	// public: ................................................................

	/**
	* An IMapper is a stateless hook for mapping a arbitrary property key
	* to another (useful, for example, for property aliasing and defaulting).
	* Each IMapper must be completely stateless and could be shared between
	* multiple IProperties instances (and invoked from multiple concurrent threads).
	*/
	interface IMapper
	{
	String getMappedKey (final String key);

	} // end of nested interface


	String getProperty (String key);
	String getProperty (String key, String dflt);
	boolean isOverridden (String key);

	IProperties copy ();
	Iterator /* String */ properties ();
	Properties toProperties ();
	/**
	* @param prefix [may not be null]
	*/
	String [] toAppArgsForm (final String prefix);
	boolean isEmpty ();
	void list (PrintStream out);
	void list (PrintWriter out);

	String setProperty (String key, String value);


	abstract class Factory
	{
	/**
	* Creates an empty IProperties set with an optional property mapper.
	*
	* @param mapper [may be null]
	* @return an empty property set [never null]
	*/
	public static IProperties create (final IMapper mapper)
	{
	return new PropertiesImpl (null, mapper);
	}

	/**
	* Converts a java.util.Properties instance to an IProperties instance,
	* with an optional property mapper. Note that 'properties' content is
	* shallowly cloned, so the result can be mutated independently from
	* the input.
	*
	* @param properties [may not be null]
	* @param mapper [may be null]
	* @return a property set based on 'properties' [never null]
	*/
	public static IProperties wrap (final Properties properties, final IMapper mapper)
	{
	final HashMap map = new HashMap ();

	// always use propertyNames() for traversing java.util.Properties:

	for (Enumeration names = properties.propertyNames (); names.hasMoreElements (); )
	{
	final String n = (String) names.nextElement ();
	final String v = properties.getProperty (n);

	map.put (n, v);
	}

	return new PropertiesImpl (map, mapper); // note: map is a defensive clone
	}

	/**
	* Combines two property sets by creating a property set that chains 'overrides'
	* to 'base' for property delegation. Note that 'overrides' are cloned
	* defensively and so the result can be mutated independently of both inputs.
	*
	* @param overrides [may be null]
	* @param base [may be null]
	* @return [never null; an empty property set with a null mapper is created
	* if both inputs are null]
	*/
	public static IProperties combine (final IProperties overrides, final IProperties base)
	{
	final IProperties result = overrides != null
	? overrides.copy ()
	: create (null);

	// [assertion: result != null]

	((PropertiesImpl) result).getLastProperties ().setDelegate ((PropertiesImpl) base);

	return result;
	}

	/*
	* Not MT-safe
	*/
	private static final class PropertiesImpl implements IProperties, Cloneable
	{
	// ACCESSORS (IProperties):

	public String getProperty (final String key)
	{
	return getProperty (key, null);
	}

	public String getProperty (final String key, final String dflt)
	{
	String value = (String) m_valueMap.get (key);

	// first, try to delegate horizontally:
	if ((value == null) && (m_mapper != null))
	{
	final String mappedKey = m_mapper.getMappedKey (key);

	if (mappedKey != null)
	value = (String) m_valueMap.get (mappedKey);
	}

	// next, try to delegate vertically:
	if ((value == null) && (m_delegate != null))
	{
	value = m_delegate.getProperty (key, null);
	}

	return value != null ? value : dflt;
	}

	public boolean isOverridden (final String key)
	{
	return m_valueMap.containsKey (key);
	}

	public IProperties copy ()
	{
	final PropertiesImpl _clone;
	try
	{
	_clone = (PropertiesImpl) super.clone ();
	}
	catch (CloneNotSupportedException cnse)
	{
	throw new Error (cnse.toString ()); // never happens
	}

	_clone.m_valueMap = (HashMap) m_valueMap.clone ();
	_clone.m_unmappedKeySet = null;

	// note: m_mapper field is not cloned by design (mappers are stateless/shareable)

	PropertiesImpl scan = _clone;
	for (PropertiesImpl delegate = m_delegate; delegate != null; delegate = delegate.m_delegate)
	{
	final PropertiesImpl _delegateClone;
	try
	{
	_delegateClone = (PropertiesImpl) delegate.clone ();
	}
	catch (CloneNotSupportedException cnse)
	{
	throw new Error (cnse.toString ()); // never happens
	}

	// note that the value map needs to be cloned not only for the
	// outermost IProperties set but for the inner ones as well
	// (to prevent independent mutation in them from showing through)

	_delegateClone.m_valueMap = (HashMap) delegate.m_valueMap.clone ();
	_delegateClone.m_unmappedKeySet = null; // ensure that the last delegate will have this field reset

	scan.setDelegate (_delegateClone);
	scan = _delegateClone;
	}

	return _clone;
	}

	public Iterator /* String */ properties ()
	{
	return unmappedKeySet ().iterator ();
	}

	public Properties toProperties ()
	{
	final Properties result = new Properties ();

	for (Iterator i = properties (); i.hasNext (); )
	{
	final String n = (String) i.next ();
	final String v = getProperty (n);

	result.setProperty (n, v);
	}

	return result;
	}

	public boolean isEmpty ()
	{
	return m_valueMap.isEmpty () && ((m_delegate == null) \|\| ((m_delegate != null) && m_delegate.isEmpty ()));
	}

	public String [] toAppArgsForm (final String prefix)
	{
	if (isEmpty ())
	return IConstants.EMPTY_STRING_ARRAY;
	else
	{
	if (prefix == null)
	throw new IllegalArgumentException ("null input: prefix");

	final List _result = new ArrayList ();
	for (Iterator names = properties (); names.hasNext (); )
	{
	final String name = (String) names.next ();
	final String value = getProperty (name, "");

	_result.add (prefix.concat (name).concat ("=").concat (value));
	}

	final String [] result = new String [_result.size ()];
	_result.toArray (result);

	return result;
	}
	}

	public void list (final PrintStream out)
	{
	if (out != null)
	{
	for (Iterator i = properties (); i.hasNext (); )
	{
	final String n = (String) i.next ();
	final String v = getProperty (n);

	out.println (n + ":\t[" + v + "]");
	}
	}
	}

	public void list (final PrintWriter out)
	{
	if (out != null)
	{
	for (Iterator i = properties (); i.hasNext (); )
	{
	final String n = (String) i.next ();
	final String v = getProperty (n);

	out.println (n + ":\t[" + v + "]");
	}
	}
	}

	// MUTATORS:

	public String setProperty (final String key, final String value)
	{
	if (value == null)
	throw new IllegalArgumentException ("null input: value");

	m_unmappedKeySet = null;

	return (String) m_valueMap.put (key, value);
	}


	PropertiesImpl (final HashMap values, final IMapper mapper)
	{
	m_mapper = mapper;
	m_valueMap = values != null ? values : new HashMap ();

	m_delegate = null;
	}


	Set unmappedKeySet ()
	{
	Set result = m_unmappedKeySet;
	if (result == null)
	{
	result = new TreeSet ();
	result.addAll (m_valueMap.keySet ());
	if (m_delegate != null)
	result.addAll (m_delegate.unmappedKeySet ());

	m_unmappedKeySet = result;
	return result;
	}

	return result;
	}

	// ACCESSORS:

	PropertiesImpl getLastProperties ()
	{
	PropertiesImpl result = this;

	for (PropertiesImpl delegate = m_delegate; delegate != null; delegate = delegate.m_delegate)
	{
	// this does not detect all possible cycles:
	if (delegate == this)
	throw new IllegalStateException ("cyclic delegation detected");

	result = delegate;
	}

	return result;
	}

	// MUTATORS:

	void setDelegate (final PropertiesImpl delegate)
	{
	m_delegate = delegate;

	m_unmappedKeySet = null;
	}


	private final IMapper m_mapper;
	private /final/ HashMap m_valueMap; // never null

	private PropertiesImpl m_delegate;
	private transient Set m_unmappedKeySet;

	} // end of nested class

	} // end of nested class

	// protected: .............................................................

	// package: ...............................................................

	// private: ...............................................................

	} // end of class
	// ----------------------------------------------------------------------------