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Groovy example source code file (SourceUnit.java)

This example Groovy source code file (SourceUnit.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

compilationfailedexception, compilerconfiguration, compilerconfiguration, errorcollector, errorcollector, groovyclassloader, io, modulenode, net, network, readersource, reduction, security, sourceunit, sourceunit, string, string, syntaxerrormessage

The Groovy SourceUnit.java source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.codehaus.groovy.control;

import groovy.lang.GroovyClassLoader;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Reader;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;

import org.codehaus.groovy.GroovyBugError;
import org.codehaus.groovy.ast.ModuleNode;
import org.codehaus.groovy.control.io.FileReaderSource;
import org.codehaus.groovy.control.io.ReaderSource;
import org.codehaus.groovy.control.io.StringReaderSource;
import org.codehaus.groovy.control.io.URLReaderSource;
import org.codehaus.groovy.control.messages.Message;
import org.codehaus.groovy.control.messages.SimpleMessage;
import org.codehaus.groovy.control.messages.SyntaxErrorMessage;
import org.codehaus.groovy.syntax.*;
import org.codehaus.groovy.tools.Utilities;

import antlr.CharScanner;
import antlr.MismatchedTokenException;
import antlr.MismatchedCharException;
import antlr.NoViableAltException;
import antlr.NoViableAltForCharException;

import com.thoughtworks.xstream.XStream;

/**
 * Provides an anchor for a single source unit (usually a script file)
 * as it passes through the compiler system.
 *
 * @author <a href="mailto:cpoirier@dreaming.org">Chris Poirier
 * @author <a href="mailto:b55r@sina.com">Bing Ran
 * @version $Id: SourceUnit.java 22163 2011-05-09 05:12:20Z paulk $
 */

public class SourceUnit extends ProcessingUnit {

    /**
     * The pluggable parser used to generate the AST - we allow
     * pluggability currently as we need to have Classic and JSR support
     */
    private ParserPlugin parserPlugin;

    /**
     * Where we can get Readers for our source unit
     */
    protected ReaderSource source;

    /**
     * A descriptive name of the source unit. This name shouldn't
     * be used for controlling the SourceUnit, it is only for error
     * messages and to determine the name of the class for
     * a script.
     */
    protected String name;

    /**
     * A Concrete Syntax Tree of the source
     */
    protected Reduction cst;

    /**
     * The root of the Abstract Syntax Tree for the source
     */
    protected ModuleNode ast;

    /**
     * Initializes the SourceUnit from existing machinery.
     */
    public SourceUnit(String name, ReaderSource source, CompilerConfiguration flags,
                      GroovyClassLoader loader, ErrorCollector er) {
        super(flags, loader, er);

        this.name = name;
        this.source = source;
    }

    /**
     * Initializes the SourceUnit from the specified file.
     */
    public SourceUnit(File source, CompilerConfiguration configuration, GroovyClassLoader loader, ErrorCollector er) {
        this(source.getPath(), new FileReaderSource(source, configuration), configuration, loader, er);
    }

    /**
     * Initializes the SourceUnit from the specified URL.
     */
    public SourceUnit(URL source, CompilerConfiguration configuration, GroovyClassLoader loader, ErrorCollector er) {
        this(source.getPath(), new URLReaderSource(source, configuration), configuration, loader, er);
    }

    /**
     * Initializes the SourceUnit for a string of source.
     */
    public SourceUnit(String name, String source, CompilerConfiguration configuration,
                      GroovyClassLoader loader, ErrorCollector er) {
        this(name, new StringReaderSource(source, configuration), configuration, loader, er);
    }

    /**
     * Returns the name for the SourceUnit. This name shouldn't
     * be used for controlling the SourceUnit, it is only for error
     * messages
     */
    public String getName() {
        return name;
    }


    /**
     * Returns the Concrete Syntax Tree produced during parse()ing.
     */
    public Reduction getCST() {
        return this.cst;
    }

    /**
     * Returns the Abstract Syntax Tree produced during convert()ing
     * and expanded during later phases.
     */
    public ModuleNode getAST() {
        return this.ast;
    }


    /**
     * Convenience routine, primarily for use by the InteractiveShell,
     * that returns true if parse() failed with an unexpected EOF.
     */
    public boolean failedWithUnexpectedEOF() {
        // Implementation note - there are several ways for the Groovy compiler
        // to report an unexpected EOF. Perhaps this implementation misses some.
        // If you find another way, please add it.
        if (getErrorCollector().hasErrors()) {
            Message last = (Message) getErrorCollector().getLastError();
            Throwable cause = null;
            if (last instanceof SyntaxErrorMessage) {
                cause = ((SyntaxErrorMessage) last).getCause().getCause();
            }
            if (cause != null) {
                if (cause instanceof NoViableAltException) {
                    return isEofToken(((NoViableAltException) cause).token);
                } else if (cause instanceof NoViableAltForCharException) {
                    char badChar = ((NoViableAltForCharException) cause).foundChar;
                    return badChar == CharScanner.EOF_CHAR;
                } else if (cause instanceof MismatchedCharException) {
                    char badChar = (char) ((MismatchedCharException) cause).foundChar;
                    return badChar == CharScanner.EOF_CHAR;
                } else if (cause instanceof MismatchedTokenException) {
                    return isEofToken(((MismatchedTokenException) cause).token);
                }
            }
        }
        return false;
    }

    protected boolean isEofToken(antlr.Token token) {
        return token.getType() == antlr.Token.EOF_TYPE;
    }


    //---------------------------------------------------------------------------
    // FACTORIES


    /**
     * A convenience routine to create a standalone SourceUnit on a String
     * with defaults for almost everything that is configurable.
     */
    public static SourceUnit create(String name, String source) {
        CompilerConfiguration configuration = new CompilerConfiguration();
        configuration.setTolerance(1);

        return new SourceUnit(name, source, configuration, null, new ErrorCollector(configuration));
    }


    /**
     * A convenience routine to create a standalone SourceUnit on a String
     * with defaults for almost everything that is configurable.
     */
    public static SourceUnit create(String name, String source, int tolerance) {
        CompilerConfiguration configuration = new CompilerConfiguration();
        configuration.setTolerance(tolerance);

        return new SourceUnit(name, source, configuration, null, new ErrorCollector(configuration));
    }

    //---------------------------------------------------------------------------
    // PROCESSING

    /**
     * Parses the source to a CST.  You can retrieve it with getCST().
     */
    public void parse() throws CompilationFailedException {
        if (this.phase > Phases.PARSING) {
            throw new GroovyBugError("parsing is already complete");
        }

        if (this.phase == Phases.INITIALIZATION) {
            nextPhase();
        }

        //
        // Create a reader on the source and run the parser.

        Reader reader = null;
        try {
            reader = source.getReader();

            // let's recreate the parser each time as it tends to keep around state
            parserPlugin = getConfiguration().getPluginFactory().createParserPlugin();

            cst = parserPlugin.parseCST(this, reader);

            reader.close();

        }
        catch (IOException e) {
            getErrorCollector().addFatalError(new SimpleMessage(e.getMessage(), this));
        }
        finally {
            if (reader != null) {
                try {
                    reader.close();
                }
                catch (IOException e) {
                    // Ignore
                }
            }
        }
    }

    /**
     * Generates an AST from the CST.  You can retrieve it with getAST().
     */
    public void convert() throws CompilationFailedException {
        if (this.phase == Phases.PARSING && this.phaseComplete) {
            gotoPhase(Phases.CONVERSION);
        }

        if (this.phase != Phases.CONVERSION) {
            throw new GroovyBugError("SourceUnit not ready for convert()");
        }

        //
        // Build the AST

        try {
            this.ast = parserPlugin.buildAST(this, this.classLoader, this.cst);
            this.ast.setDescription(this.name);
        }
        catch (SyntaxException e) {
            if (this.ast == null) {
                // Create a dummy ModuleNode to represent a failed parse - in case a later phase attempts to use the ast
                this.ast = new ModuleNode(this);
            }
            getErrorCollector().addError(new SyntaxErrorMessage(e, this));
        }

        String property = (String) AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                return System.getProperty("groovy.ast");
            }
        });

        if ("xml".equals(property)) {
            saveAsXML(name, ast);
        }
    }

    private void saveAsXML(String name, ModuleNode ast) {
        XStream xstream = new XStream();
        try {
            xstream.toXML(ast, new FileWriter(name + ".xml"));
            System.out.println("Written AST to " + name + ".xml");
        } catch (Exception e) {
            System.out.println("Couldn't write to " + name + ".xml");
            e.printStackTrace();
        }
    }

    //---------------------------------------------------------------------------    // SOURCE SAMPLING

    /**
     * Returns a sampling of the source at the specified line and column,
     * of null if it is unavailable.
     */
    public String getSample(int line, int column, Janitor janitor) {
        String sample = null;
        String text = source.getLine(line, janitor);

        if (text != null) {
            if (column > 0) {
                String marker = Utilities.repeatString(" ", column - 1) + "^";

                if (column > 40) {
                    int start = column - 30 - 1;
                    int end = (column + 10 > text.length() ? text.length() : column + 10 - 1);
                    sample = "   " + text.substring(start, end) + Utilities.eol() + "   " +
                            marker.substring(start, marker.length());
                } else {
                    sample = "   " + text + Utilities.eol() + "   " + marker;
                }
            } else {
                sample = text;
            }
        }

        return sample;
    }

    /**
     * This method adds an exception to the error collector. The Exception most likely has no line number attached to it.
     * For this reason you should use this method sparingly. Prefer using addError for syntax errors or add an error
     * to the {@link ErrorCollector} directly by retrieving it with getErrorCollector().
     * @param e
     *      the exception that occurred
     * @throws CompilationFailedException
     *      on error
     */
    public void addException(Exception e) throws CompilationFailedException {
        getErrorCollector().addException(e, this);
    }

    /**
     * This method adds a SyntaxException to the error collector. The exception should specify the line and column
     * number of the error.  This method should be reserved for real errors in the syntax of the SourceUnit. If
     * your error is not in syntax, and is a semantic error, or more general error, then use addException or use
     * the error collector directly by retrieving it with getErrorCollector().
     * @param se
     *      the exception, which should have line and column information
     * @throws CompilationFailedException
     *      on error
     */
    public void addError(SyntaxException se) throws CompilationFailedException {
        getErrorCollector().addError(se, this);
    }

    public ReaderSource getSource() { return source; }
}

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