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/jEdit/tags/jedit-4-1-pre5/bsh/BlockNameSpace.java

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Java | 118 lines | 34 code | 13 blank | 71 comment | 3 complexity | e460af04d373fc10144b29d1fdef4076 MD5 | raw file
  1/*****************************************************************************
  2 *                                                                           *
  3 *  This file is part of the BeanShell Java Scripting distribution.          *
  4 *  Documentation and updates may be found at http://www.beanshell.org/      *
  5 *                                                                           *
  6 *  Sun Public License Notice:                                               *
  7 *                                                                           *
  8 *  The contents of this file are subject to the Sun Public License Version  *
  9 *  1.0 (the "License"); you may not use this file except in compliance with *
 10 *  the License. A copy of the License is available at http://www.sun.com    * 
 11 *                                                                           *
 12 *  The Original Code is BeanShell. The Initial Developer of the Original    *
 13 *  Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright     *
 14 *  (C) 2000.  All Rights Reserved.                                          *
 15 *                                                                           *
 16 *  GNU Public License Notice:                                               *
 17 *                                                                           *
 18 *  Alternatively, the contents of this file may be used under the terms of  *
 19 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 20 *  provisions of LGPL are applicable instead of those above. If you wish to *
 21 *  allow use of your version of this file only under the  terms of the LGPL *
 22 *  and not to allow others to use your version of this file under the SPL,  *
 23 *  indicate your decision by deleting the provisions above and replace      *
 24 *  them with the notice and other provisions required by the LGPL.  If you  *
 25 *  do not delete the provisions above, a recipient may use your version of  *
 26 *  this file under either the SPL or the LGPL.                              *
 27 *                                                                           *
 28 *  Patrick Niemeyer (pat@pat.net)                                           *
 29 *  Author of Learning Java, O'Reilly & Associates                           *
 30 *  http://www.pat.net/~pat/                                                 *
 31 *                                                                           *
 32 *****************************************************************************/
 33
 34
 35package	bsh;
 36
 37/**
 38    A specialized namespace	for Blocks, e.g. the body of a "for" statement.
 39	The Block acts like a child namespace but only for typed variables 
 40	declared within it.  Elsewhere variable assignment (including untyped
 41	variable usage) acts like it is part of the containing block.  
 42	<p>
 43
 44	Note: It *must* remain possible for a BlockNameSpace to be a child of
 45	another BlockNameSpace and have variable propogation pass all the way
 46	through.  (This happens naturally and simply here). This is used in 
 47	BSHForStatement (see notes there).
 48*/
 49class BlockNameSpace extends NameSpace 
 50{
 51	/** When true, capture all variable assignment locally */
 52	boolean initMode;
 53
 54    public BlockNameSpace( NameSpace parent ) 
 55		throws EvalError
 56	{
 57		super( parent, parent.name + "/BlockNameSpace" );
 58    }
 59
 60	/**
 61		Override the standard namespace behavior.
 62		If the variables exists in our namespace assign it there,
 63		otherwise in the parent space.
 64		i.e. only allow typed var declaration to happen in this namespace.
 65		Typed vars are handled in the ordinary way... local scope.
 66	*/
 67    public void	setVariable(String name, Object	o) throws EvalError {
 68		if ( weHaveVar( name ) || initMode ) 
 69			super.setVariable( name, o );
 70		else
 71			getParent().setVariable( name, o );
 72    }
 73
 74	/**
 75		When set to true, handle all variable assignment in this local
 76		scope - don't delegate to parent.  This is used in catch blocks
 77		to initialize local parameters to the block then turned off to allow 
 78		the normal BlockNameSpace behavior (which is to keep only locally 
 79		declared typed variables local and pass the rest to the parent).
 80	*/
 81	public void setInitMode( boolean b ) {
 82		initMode = b;
 83	}
 84
 85	boolean weHaveVar( String name ) {
 86		return super.getVariableImpl( name, false ) != null;
 87	}
 88
 89	/**
 90		super is our parent's super
 91	*/
 92    public NameSpace getSuper() {
 93		return getParent().getSuper();
 94	}
 95
 96	/**
 97		this is our parent's this
 98	*/
 99    This getThis( Interpreter declaringInterpreter ) {
100		return getParent().getThis( declaringInterpreter );
101	}
102
103	/**
104		delegate import to our parent
105	*/
106    public void	importClass(String name) {
107		getParent().importClass( name );
108	}
109
110	/**
111		delegate import to our parent
112	*/
113    public void	importPackage(String name) {
114		getParent().importPackage( name );
115	}
116
117}
118