PageRenderTime 45ms CodeModel.GetById 35ms app.highlight 6ms RepoModel.GetById 1ms app.codeStats 1ms

/jEdit/tags/jedit-4-2-pre14/bsh/LHS.java

#
Java | 270 lines | 159 code | 26 blank | 85 comment | 28 complexity | 0770b9fde8ca68723d6e20f8c07e245e 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
 37import java.lang.reflect.Field;
 38import java.util.Hashtable;
 39
 40/**
 41	An LHS is a wrapper for an variable, field, or property.  It ordinarily 
 42	holds the "left hand side" of an assignment and may be either resolved to 
 43	a value or assigned a value.
 44	<p>
 45	
 46	There is one special case here termed METHOD_EVAL where the LHS is used
 47	in an intermediate evaluation of a chain of suffixes and wraps a method
 48	invocation.  In this case it may only be resolved to a value and cannot be 
 49	assigned.  (You can't assign a value to the result of a method call e.g.
 50	"foo() = 5;").
 51	<p>
 52*/
 53class LHS implements ParserConstants, java.io.Serializable
 54{
 55	NameSpace nameSpace;
 56	/** The assignment should be to a local variable */
 57	boolean localVar;
 58
 59	/**
 60		Identifiers for the various types of LHS.
 61	*/
 62	static final int
 63		VARIABLE = 0,
 64		FIELD = 1,
 65		PROPERTY = 2,
 66		INDEX = 3,
 67		METHOD_EVAL = 4;
 68
 69	int type;
 70
 71	String varName;
 72	String propName;
 73	Field field;
 74	Object object;
 75	int index;
 76
 77/**
 78		Variable LHS constructor.
 79*/
 80	LHS( NameSpace nameSpace, String varName )
 81	{
 82throw new Error("namespace lhs");
 83/*
 84		type = VARIABLE;
 85		this.varName = varName;
 86		this.nameSpace = nameSpace;
 87*/
 88	}
 89
 90	/**
 91		@param localVar if true the variable is set directly in the This
 92		reference's local scope.  If false recursion to look for the variable
 93		definition in parent's scope is allowed. (e.g. the default case for
 94		undefined vars going to global).
 95	*/
 96	LHS( NameSpace nameSpace, String varName, boolean localVar )
 97	{
 98		type = VARIABLE;
 99		this.localVar = localVar;
100		this.varName = varName;
101		this.nameSpace = nameSpace;
102	}
103
104	/**
105		Static field LHS Constructor.
106		This simply calls Object field constructor with null object.
107	*/
108	LHS( Field field )
109	{
110		type = FIELD;
111		this.object = null;
112		this.field = field;
113	}
114
115	/**
116		Object field LHS Constructor.
117	*/
118	LHS( Object object, Field field )
119	{
120		if ( object == null)
121			throw new NullPointerException("constructed empty LHS");
122
123		type = FIELD;
124		this.object = object;
125		this.field = field;
126	}
127
128	/**
129		Object property LHS Constructor.
130	*/
131	LHS( Object object, String propName )
132	{
133		if(object == null)
134			throw new NullPointerException("constructed empty LHS");
135
136		type = PROPERTY;
137		this.object = object;
138		this.propName = propName;
139	}
140
141	/**
142		Array index LHS Constructor.
143	*/
144	LHS( Object array, int index )
145	{
146		if(array == null)
147			throw new NullPointerException("constructed empty LHS");
148
149		type = INDEX;
150		this.object = array;
151		this.index = index;
152	}
153
154	public Object getValue() throws UtilEvalError
155	{
156		if ( type == VARIABLE )
157			return nameSpace.getVariable( varName );
158
159		if (type == FIELD)
160			try {
161				Object o = field.get( object );
162				return Primitive.wrap( o, field.getType() );
163			} catch(IllegalAccessException e2) {
164				throw new UtilEvalError("Can't read field: " + field);
165			}
166
167		if ( type == PROPERTY )
168			try {
169				return Reflect.getObjectProperty(object, propName);
170			}
171			catch(ReflectError e) {
172				Interpreter.debug(e.getMessage());
173				throw new UtilEvalError("No such property: " + propName);
174			}
175
176		if ( type == INDEX )
177			try {
178				return Reflect.getIndex(object, index);
179			}
180			catch(Exception e) {
181				throw new UtilEvalError("Array access: " + e);
182			}
183
184		throw new InterpreterError("LHS type");
185	}
186
187	/**
188		Assign a value to the LHS.
189	*/
190	public Object assign( Object val, boolean strictJava ) 
191		throws UtilEvalError
192	{
193		if ( type == VARIABLE )
194		{
195			// Set the variable in namespace according to localVar flag
196			if ( localVar )
197				nameSpace.setLocalVariable( varName, val, strictJava );
198			else
199				nameSpace.setVariable( varName, val, strictJava );
200		} else 
201		if ( type == FIELD )
202		{
203			try {
204				Object fieldVal = val instanceof Primitive ?  
205					((Primitive)val).getValue() : val;
206
207				// This should probably be in Reflect.java
208				ReflectManager.RMSetAccessible( field );
209				field.set( object, fieldVal );
210				return val;
211			}
212			catch( NullPointerException e) {   
213    			throw new UtilEvalError(
214					"LHS ("+field.getName()+") not a static field.");
215			}     
216   			catch( IllegalAccessException e2) {   
217				throw new UtilEvalError(
218					"LHS ("+field.getName()+") can't access field: "+e2);
219			}     
220			catch( IllegalArgumentException e3) 
221			{
222				String type = val instanceof Primitive ?
223					((Primitive)val).getType().getName()
224					: val.getClass().getName();
225				throw new UtilEvalError(
226					"Argument type mismatch. " + (val == null ? "null" : type )
227					+ " not assignable to field "+field.getName());
228			}
229		}
230		else 
231		if ( type == PROPERTY )
232		{
233			/*
234			if ( object instanceof Hashtable )
235				((Hashtable)object).put(propName, val);
236			*/
237			CollectionManager cm = CollectionManager.getCollectionManager();
238			if ( cm.isMap( object ) )
239				cm.putInMap( object/*map*/, propName, val );
240			else
241				try {
242					Reflect.setObjectProperty(object, propName, val);
243				}
244				catch(ReflectError e) {
245					Interpreter.debug("Assignment: " + e.getMessage());
246					throw new UtilEvalError("No such property: " + propName);
247				}
248		} else 
249		if ( type == INDEX )
250			try {
251				Reflect.setIndex(object, index, val);
252			} catch ( UtilTargetError e1 ) { // pass along target error
253				throw e1;
254			} catch ( Exception e ) {
255				throw new UtilEvalError("Assignment: " + e.getMessage());
256			}
257		else
258			throw new InterpreterError("unknown lhs");
259
260		return val;
261	}
262
263	public String toString() { 
264		return "LHS: "
265			+((field!=null)? "field = "+field.toString():"")
266			+(varName!=null ? " varName = "+varName: "")
267			+(nameSpace!=null ? " nameSpace = "+nameSpace.toString(): "");
268	}
269}
270