Source code

001package org.apache.maven.plugins.enforcer;
002
003import org.apache.maven.plugin.AbstractMojo;
004import org.apache.maven.plugin.MojoExecutionException;
005import org.apache.maven.plugins.annotations.Mojo;
006import org.apache.maven.plugins.annotations.Parameter;
007
008import org.w3c.dom.Document;
009import org.w3c.dom.Element;
010import org.w3c.dom.Node;
011import org.w3c.dom.NodeList;
012import org.xml.sax.SAXException;
013
014import javax.xml.parsers.DocumentBuilder;
015import javax.xml.parsers.DocumentBuilderFactory;
016import javax.xml.parsers.ParserConfigurationException;
017import java.io.IOException;
018import java.io.InputStream;
019import java.util.ArrayList;
020import java.util.List;
021
022/**
023 * Display help information on maven-enforcer-plugin.<br>
024 * Call <code>mvn enforcer:help -Ddetail=true -Dgoal=&lt;goal-name&gt;</code> to display parameter details.
025 * @author maven-plugin-tools
026 */
027@Mojo( name = "help", requiresProject = false, threadSafe = true )
028public class HelpMojo
029    extends AbstractMojo
030{
031    /**
032     * If <code>true</code>, display all settable properties for each goal.
033     *
034     */
035    @Parameter( property = "detail", defaultValue = "false" )
036    private boolean detail;
037
038    /**
039     * The name of the goal for which to show help. If unspecified, all goals will be displayed.
040     *
041     */
042    @Parameter( property = "goal" )
043    private java.lang.String goal;
044
045    /**
046     * The maximum length of a display line, should be positive.
047     *
048     */
049    @Parameter( property = "lineLength", defaultValue = "80" )
050    private int lineLength;
051
052    /**
053     * The number of spaces per indentation level, should be positive.
054     *
055     */
056    @Parameter( property = "indentSize", defaultValue = "2" )
057    private int indentSize;
058
059    // /META-INF/maven/<groupId>/<artifactId>/plugin-help.xml
060    private static final String PLUGIN_HELP_PATH =
061                    "/META-INF/maven/org.apache.maven.plugins/maven-enforcer-plugin/plugin-help.xml";
062
063    private static final int DEFAULT_LINE_LENGTH = 80;
064
065    private Document build()
066        throws MojoExecutionException
067    {
068        getLog().debug( "load plugin-help.xml: " + PLUGIN_HELP_PATH );
069        try ( InputStream is = getClass().getResourceAsStream( PLUGIN_HELP_PATH ) )
070        {
071            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
072            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
073            return dBuilder.parse( is );
074        }
075        catch ( IOException e )
076        {
077            throw new MojoExecutionException( e.getMessage(), e );
078        }
079        catch ( ParserConfigurationException e )
080        {
081            throw new MojoExecutionException( e.getMessage(), e );
082        }
083        catch ( SAXException e )
084        {
085            throw new MojoExecutionException( e.getMessage(), e );
086        }
087    }
088
089    /**
090     * {@inheritDoc}
091     */
092    @Override
093    public void execute()
094        throws MojoExecutionException
095    {
096        if ( lineLength <= 0 )
097        {
098            getLog().warn( "The parameter 'lineLength' should be positive, using '80' as default." );
099            lineLength = DEFAULT_LINE_LENGTH;
100        }
101        if ( indentSize <= 0 )
102        {
103            getLog().warn( "The parameter 'indentSize' should be positive, using '2' as default." );
104            indentSize = 2;
105        }
106
107        Document doc = build();
108
109        StringBuilder sb = new StringBuilder();
110        Node plugin = getSingleChild( doc, "plugin" );
111
112
113        String name = getValue( plugin, "name" );
114        String version = getValue( plugin, "version" );
115        String id = getValue( plugin, "groupId" ) + ":" + getValue( plugin, "artifactId" ) + ":" + version;
116        if ( isNotEmpty( name ) && !name.contains( id ) )
117        {
118            append( sb, name + " " + version, 0 );
119        }
120        else
121        {
122            if ( isNotEmpty( name ) )
123            {
124                append( sb, name, 0 );
125            }
126            else
127            {
128                append( sb, id, 0 );
129            }
130        }
131        append( sb, getValue( plugin, "description" ), 1 );
132        append( sb, "", 0 );
133
134        //<goalPrefix>plugin</goalPrefix>
135        String goalPrefix = getValue( plugin, "goalPrefix" );
136
137        Node mojos1 = getSingleChild( plugin, "mojos" );
138
139        List<Node> mojos = findNamedChild( mojos1, "mojo" );
140
141        if ( goal == null || goal.length() <= 0 )
142        {
143            append( sb, "This plugin has " + mojos.size() + ( mojos.size() > 1 ? " goals:" : " goal:" ), 0 );
144            append( sb, "", 0 );
145        }
146
147        for ( Node mojo : mojos )
148        {
149            writeGoal( sb, goalPrefix, (Element) mojo );
150        }
151
152        if ( getLog().isInfoEnabled() )
153        {
154            getLog().info( sb.toString() );
155        }
156    }
157
158
159    private static boolean isNotEmpty( String string )
160    {
161        return string != null && string.length() > 0;
162    }
163
164    private static String getValue( Node node, String elementName )
165        throws MojoExecutionException
166    {
167        return getSingleChild( node, elementName ).getTextContent();
168    }
169
170    private static Node getSingleChild( Node node, String elementName )
171        throws MojoExecutionException
172    {
173        List<Node> namedChild = findNamedChild( node, elementName );
174        if ( namedChild.isEmpty() )
175        {
176            throw new MojoExecutionException( "Could not find " + elementName + " in plugin-help.xml" );
177        }
178        if ( namedChild.size() > 1 )
179        {
180            throw new MojoExecutionException( "Multiple " + elementName + " in plugin-help.xml" );
181        }
182        return namedChild.get( 0 );
183    }
184
185    private static List<Node> findNamedChild( Node node, String elementName )
186    {
187        List<Node> result = new ArrayList<Node>();
188        NodeList childNodes = node.getChildNodes();
189        for ( int i = 0; i < childNodes.getLength(); i++ )
190        {
191            Node item = childNodes.item( i );
192            if ( elementName.equals( item.getNodeName() ) )
193            {
194                result.add( item );
195            }
196        }
197        return result;
198    }
199
200    private static Node findSingleChild( Node node, String elementName )
201        throws MojoExecutionException
202    {
203        List<Node> elementsByTagName = findNamedChild( node, elementName );
204        if ( elementsByTagName.isEmpty() )
205        {
206            return null;
207        }
208        if ( elementsByTagName.size() > 1 )
209        {
210            throw new MojoExecutionException( "Multiple " + elementName + "in plugin-help.xml" );
211        }
212        return elementsByTagName.get( 0 );
213    }
214
215    private void writeGoal( StringBuilder sb, String goalPrefix, Element mojo )
216        throws MojoExecutionException
217    {
218        String mojoGoal = getValue( mojo, "goal" );
219        Node configurationElement = findSingleChild( mojo, "configuration" );
220        Node description = findSingleChild( mojo, "description" );
221        if ( goal == null || goal.length() <= 0 || mojoGoal.equals( goal ) )
222        {
223            append( sb, goalPrefix + ":" + mojoGoal, 0 );
224            Node deprecated = findSingleChild( mojo, "deprecated" );
225            if ( ( deprecated != null ) && isNotEmpty( deprecated.getTextContent() ) )
226            {
227                append( sb, "Deprecated. " + deprecated.getTextContent(), 1 );
228                if ( detail && description != null )
229                {
230                    append( sb, "", 0 );
231                    append( sb, description.getTextContent(), 1 );
232                }
233            }
234            else if ( description != null )
235            {
236                append( sb, description.getTextContent(), 1 );
237            }
238            append( sb, "", 0 );
239
240            if ( detail )
241            {
242                Node parametersNode = getSingleChild( mojo, "parameters" );
243                List<Node> parameters = findNamedChild( parametersNode, "parameter" );
244                append( sb, "Available parameters:", 1 );
245                append( sb, "", 0 );
246
247                for ( Node parameter : parameters )
248                {
249                    writeParameter( sb, parameter, configurationElement );
250                }
251            }
252        }
253    }
254
255    private void writeParameter( StringBuilder sb, Node parameter, Node configurationElement )
256        throws MojoExecutionException
257    {
258        String parameterName = getValue( parameter, "name" );
259        String parameterDescription = getValue( parameter, "description" );
260
261        Element fieldConfigurationElement = null;
262        if ( configurationElement != null )
263        {
264          fieldConfigurationElement =  (Element) findSingleChild( configurationElement, parameterName );
265        }
266
267        String parameterDefaultValue = "";
268        if ( fieldConfigurationElement != null && fieldConfigurationElement.hasAttribute( "default-value" ) )
269        {
270            parameterDefaultValue = " (Default: " + fieldConfigurationElement.getAttribute( "default-value" ) + ")";
271        }
272        append( sb, parameterName + parameterDefaultValue, 2 );
273        Node deprecated = findSingleChild( parameter, "deprecated" );
274        if ( ( deprecated != null ) && isNotEmpty( deprecated.getTextContent() ) )
275        {
276            append( sb, "Deprecated. " + deprecated.getTextContent(), 3 );
277            append( sb, "", 0 );
278        }
279        append( sb, parameterDescription, 3 );
280        if ( "true".equals( getValue( parameter, "required" ) ) )
281        {
282            append( sb, "Required: Yes", 3 );
283        }
284        if ( ( fieldConfigurationElement != null ) && isNotEmpty( fieldConfigurationElement.getTextContent() ) )
285        {
286            String property = getPropertyFromExpression( fieldConfigurationElement.getTextContent() );
287            append( sb, "User property: " + property, 3 );
288        }
289
290        append( sb, "", 0 );
291    }
292
293    /**
294     * <p>Repeat a String <code>n</code> times to form a new string.</p>
295     *
296     * @param str    String to repeat
297     * @param repeat number of times to repeat str
298     * @return String with repeated String
299     * @throws NegativeArraySizeException if <code>repeat &lt; 0</code>
300     * @throws NullPointerException       if str is <code>null</code>
301     */
302    private static String repeat( String str, int repeat )
303    {
304        StringBuilder buffer = new StringBuilder( repeat * str.length() );
305
306        for ( int i = 0; i < repeat; i++ )
307        {
308            buffer.append( str );
309        }
310
311        return buffer.toString();
312    }
313
314    /**
315     * Append a description to the buffer by respecting the indentSize and lineLength parameters.
316     * <b>Note</b>: The last character is always a new line.
317     *
318     * @param sb          The buffer to append the description, not <code>null</code>.
319     * @param description The description, not <code>null</code>.
320     * @param indent      The base indentation level of each line, must not be negative.
321     */
322    private void append( StringBuilder sb, String description, int indent )
323    {
324        for ( String line : toLines( description, indent, indentSize, lineLength ) )
325        {
326            sb.append( line ).append( '\n' );
327        }
328    }
329
330    /**
331     * Splits the specified text into lines of convenient display length.
332     *
333     * @param text       The text to split into lines, must not be <code>null</code>.
334     * @param indent     The base indentation level of each line, must not be negative.
335     * @param indentSize The size of each indentation, must not be negative.
336     * @param lineLength The length of the line, must not be negative.
337     * @return The sequence of display lines, never <code>null</code>.
338     * @throws NegativeArraySizeException if <code>indent &lt; 0</code>
339     */
340    private static List<String> toLines( String text, int indent, int indentSize, int lineLength )
341    {
342        List<String> lines = new ArrayList<String>();
343
344        String ind = repeat( "\t", indent );
345
346        String[] plainLines = text.split( "(\r\n)|(\r)|(\n)" );
347
348        for ( String plainLine : plainLines )
349        {
350            toLines( lines, ind + plainLine, indentSize, lineLength );
351        }
352
353        return lines;
354    }
355
356    /**
357     * Adds the specified line to the output sequence, performing line wrapping if necessary.
358     *
359     * @param lines      The sequence of display lines, must not be <code>null</code>.
360     * @param line       The line to add, must not be <code>null</code>.
361     * @param indentSize The size of each indentation, must not be negative.
362     * @param lineLength The length of the line, must not be negative.
363     */
364    private static void toLines( List<String> lines, String line, int indentSize, int lineLength )
365    {
366        int lineIndent = getIndentLevel( line );
367        StringBuilder buf = new StringBuilder( 256 );
368
369        String[] tokens = line.split( " +" );
370
371        for ( String token : tokens )
372        {
373            if ( buf.length() > 0 )
374            {
375                if ( buf.length() + token.length() >= lineLength )
376                {
377                    lines.add( buf.toString() );
378                    buf.setLength( 0 );
379                    buf.append( repeat( " ", lineIndent * indentSize ) );
380                }
381                else
382                {
383                    buf.append( ' ' );
384                }
385            }
386
387            for ( int j = 0; j < token.length(); j++ )
388            {
389                char c = token.charAt( j );
390                if ( c == '\t' )
391                {
392                    buf.append( repeat( " ", indentSize - buf.length() % indentSize ) );
393                }
394                else if ( c == '\u00A0' )
395                {
396                    buf.append( ' ' );
397                }
398                else
399                {
400                    buf.append( c );
401                }
402            }
403        }
404        lines.add( buf.toString() );
405    }
406
407    /**
408     * Gets the indentation level of the specified line.
409     *
410     * @param line The line whose indentation level should be retrieved, must not be <code>null</code>.
411     * @return The indentation level of the line.
412     */
413    private static int getIndentLevel( String line )
414    {
415        int level = 0;
416        for ( int i = 0; i < line.length() && line.charAt( i ) == '\t'; i++ )
417        {
418            level++;
419        }
420        for ( int i = level + 1; i <= level + 4 && i < line.length(); i++ )
421        {
422            if ( line.charAt( i ) == '\t' )
423            {
424                level++;
425                break;
426            }
427        }
428        return level;
429    }
430    
431    private static String getPropertyFromExpression( String expression )
432    {
433        if ( expression != null && expression.startsWith( "${" ) && expression.endsWith( "}" )
434            && !expression.substring( 2 ).contains( "${" ) )
435        {
436            // expression="${xxx}" -> property="xxx"
437            return expression.substring( 2, expression.length() - 1 );
438        }
439        // no property can be extracted
440        return null;
441    }
442}