001/* An actor that reads a string from a file or URL, parses it assuming it is defining a record, and outputs the record.
002
003 Copyright (c) 2003-2015 The Regents of the University of California.
004 All rights reserved.
005 Permission is hereby granted, without written agreement and without
006 license or royalty fees, to use, copy, modify, and distribute this
007 software and its documentation for any purpose, provided that the above
008 copyright notice and the following two paragraphs appear in all copies
009 of this software.
010
011 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
012 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
013 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
014 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
015 SUCH DAMAGE.
016
017 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
018 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
019 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
020 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
021 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
022 ENHANCEMENTS, OR MODIFICATIONS.
023
024 PT_COPYRIGHT_VERSION_2
025 COPYRIGHTENDKEY
026 */
027package ptolemy.actor.lib.io;
028
029import java.util.Set;
030
031import ptolemy.data.Token;
032import ptolemy.data.expr.ASTPtRootNode;
033import ptolemy.data.expr.Parameter;
034import ptolemy.data.expr.ParseTreeEvaluator;
035import ptolemy.data.expr.PtParser;
036import ptolemy.data.expr.StringParameter;
037import ptolemy.data.type.BaseType;
038import ptolemy.graph.Inequality;
039import ptolemy.kernel.CompositeEntity;
040import ptolemy.kernel.util.IllegalActionException;
041import ptolemy.kernel.util.NameDuplicationException;
042
043///////////////////////////////////////////////////////////////////
044//// TokenReader
045
046/**
047 An actor that reads a string expression from a file or URL upon receiving a
048 signal on its <i>trigger</i> input port, and outputs a token that is the
049 result of evaluating the read string. The file or URL is specified by the
050 <i>FileOrURL</i> parameter or set using the <i>FileOrURL</i> port. If the
051 file or URL cannot be read, the expression cannot be parsed successfully,
052 or the resulting token does not match the type constraint of the output port,
053 the value of the <i>errorHandlingStrategy</i> parameter determines the
054 behavior of this actor.
055 TODO: describe automatic port constraint setting
056 FIXME: More here. Particularly, document output type handling.
057
058 @author Edward A. Lee, Marten Lohstroh
059 @version $Id$
060 @since Ptolemy II 10.0
061 @deprecated Use LineReader followed by ExpressionToToken.
062 @Pt.ProposedRating Red (eal)
063 @Pt.AcceptedRating Red (reviewmoderator)
064 */
065@Deprecated
066public class TokenReader extends FileReader {
067
068    /** Construct an actor with a name and a container.
069     *  The container argument must not be null, or a NullPointerException
070     *  will be thrown.
071     *  @param container The container.
072     *  @param name The name of this actor.
073     *  @exception IllegalActionException If the container is incompatible
074     *   with this actor.
075     *  @exception NameDuplicationException If the name coincides with
076     *   an actor already in the container.
077     */
078    public TokenReader(CompositeEntity container, String name)
079            throws IllegalActionException, NameDuplicationException {
080        super(container, name);
081        outputType = new Parameter(this, "outputType");
082        // must reset the output type to unknown (base class sets it to string)
083        output.setTypeEquals(BaseType.UNKNOWN);
084
085        errorHandlingStrategy = new StringParameter(this,
086                "errorHandlingStrategy");
087        errorHandlingStrategy.addChoice("Throw Exception");
088        errorHandlingStrategy.addChoice("Do Nothing");
089
090        // Show the firingCountLimit parameter last.
091        firingCountLimit.moveToLast();
092    }
093
094    ///////////////////////////////////////////////////////////////////
095    ////                         public variables                  ////
096
097    /** The error handled strategy.  The strategy to use if:
098     *  <ul>
099     *  <li> the file or URL cannot be read,</li>
100     *  <li> the data read from the file or the URL cannot be parsed,</li>
101     *  <li> the parsed token cannot be converted into a token of the type
102     *  given by <i>outputType</i>, if such a type is given, or</li>
103     *  <li> the parsed token cannot
104     *  be converted to a token of the resolved type of the output, if no <i>outputType</i>
105     *  is given.</li>
106     *  </ul>
107     *  This is a string that has the following
108     *  possible values: "Do Nothing" or "Throw Exception", where
109     *  "Throw Exception" is the default.
110     */
111    public StringParameter errorHandlingStrategy;
112
113    /** If this parameter has a value, then the value specifies the
114     *  type of the output port. When the actor reads from the file
115     *  or URL, it expects the data read to be a string that can be
116     *  parsed into a token that is convertible to (or identical to)
117     *  this output type. If it is not, then the action taken is
118     *  specified by the <i>errorHandlingStrategy</i> parameter.
119     *  If this parameter has no value (the default), then the
120     *  output type will be set to match whatever is first read from the
121     *  file or URL and will be updated on each subsequent firing if
122     *  the data read from the file or URL cannot be converted to the
123     *  type determined by the first read.
124     */
125    public Parameter outputType;
126
127    ///////////////////////////////////////////////////////////////////
128    ////                         public methods                    ////
129
130    /** Not implemented entirely yet. FIXME
131     *  @exception IllegalActionException If thrown by the base class.
132     */
133    @Override
134    public void fire() throws IllegalActionException {
135        try {
136            super.fire();
137        } catch (IllegalActionException exception) {
138            String errorHandlingStrategyValue = errorHandlingStrategy
139                    .stringValue();
140            if (errorHandlingStrategyValue.equals("Throw Exception")) {
141                throw exception;
142            }
143        }
144    }
145
146    ///////////////////////////////////////////////////////////////////
147    ////                         protected methods                 ////
148
149    /** Do not establish the usual default type constraints.
150     *  @return null
151     */
152    @Override
153    protected Set<Inequality> _defaultTypeConstraints() {
154        return null;
155    }
156
157    /** FIXME: Send the specified string to the output.
158     *  @param fileContents The contents of the file or URL that was read.
159     *  @exception IllegalActionException If sending the data fails.
160     */
161    @Override
162    protected void _handleFileData(String fileContents)
163            throws IllegalActionException {
164
165        if (_parser == null) {
166            _parser = new PtParser();
167        }
168        ASTPtRootNode parseTree = _parser.generateParseTree(fileContents);
169
170        if (_parseTreeEvaluator == null) {
171            _parseTreeEvaluator = new ParseTreeEvaluator();
172        }
173
174        // FIXME: Evaluating a parse tree that comes from an untrusted
175        // source creates a security problem.
176        Token result = _parseTreeEvaluator.evaluateParseTree(parseTree);
177
178        if (result == null) {
179            throw new IllegalActionException(this,
180                    "Expression yields a null result: " + fileContents);
181        }
182
183        if (!output.getType().isCompatible(result.getType())) {
184            // Handle the error according to the error policy.
185            // FIXME: Fall through to the broadcast, which will throw
186            // an exception.
187        }
188        output.broadcast(result);
189    }
190
191    ///////////////////////////////////////////////////////////////////
192    ////                         private members                   ////
193
194    /** The parser to use. */
195    private PtParser _parser = null;
196
197    /** The parse tree evaluator to use. */
198    private ParseTreeEvaluator _parseTreeEvaluator = null;
199
200}