Java tutorial
package org.apache.maven.project.interpolation; /* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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. */ import org.apache.maven.model.Model; import org.apache.maven.model.io.xpp3.MavenXpp3Reader; import org.apache.maven.model.io.xpp3.MavenXpp3Writer; import org.apache.maven.project.DefaultProjectBuilderConfiguration; import org.apache.maven.project.ProjectBuilderConfiguration; import org.apache.maven.project.path.PathTranslator; import org.codehaus.plexus.component.annotations.Requirement; import org.codehaus.plexus.interpolation.AbstractValueSource; import org.codehaus.plexus.interpolation.InterpolationException; import org.codehaus.plexus.interpolation.InterpolationPostProcessor; import org.codehaus.plexus.interpolation.Interpolator; import org.codehaus.plexus.interpolation.MapBasedValueSource; import org.codehaus.plexus.interpolation.ObjectBasedValueSource; import org.codehaus.plexus.interpolation.PrefixAwareRecursionInterceptor; import org.codehaus.plexus.interpolation.PrefixedObjectValueSource; import org.codehaus.plexus.interpolation.PrefixedValueSourceWrapper; import org.codehaus.plexus.interpolation.RecursionInterceptor; import org.codehaus.plexus.interpolation.ValueSource; import org.codehaus.plexus.logging.AbstractLogEnabled; import org.codehaus.plexus.logging.Logger; import org.codehaus.plexus.personality.plexus.lifecycle.phase.Initializable; import org.codehaus.plexus.personality.plexus.lifecycle.phase.InitializationException; import org.codehaus.plexus.util.xml.pull.XmlPullParserException; import java.io.File; import java.io.IOException; import java.io.StringReader; import java.io.StringWriter; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.Properties; /** * Use a regular expression search to find and resolve expressions within the POM. * * @author jdcasey Created on Feb 3, 2005 * TODO Consolidate this logic with the PluginParameterExpressionEvaluator, minus deprecations/bans. */ @Deprecated public abstract class AbstractStringBasedModelInterpolator extends AbstractLogEnabled implements ModelInterpolator, Initializable { private static final List<String> PROJECT_PREFIXES = Arrays.asList("pom.", "project."); private static final List<String> TRANSLATED_PATH_EXPRESSIONS; static { List<String> translatedPrefixes = new ArrayList<>(); // MNG-1927, MNG-2124, MNG-3355: // If the build section is present and the project directory is non-null, we should make // sure interpolation of the directories below uses translated paths. // Afterward, we'll double back and translate any paths that weren't covered during interpolation via the // code below... translatedPrefixes.add("build.directory"); translatedPrefixes.add("build.outputDirectory"); translatedPrefixes.add("build.testOutputDirectory"); translatedPrefixes.add("build.sourceDirectory"); translatedPrefixes.add("build.testSourceDirectory"); translatedPrefixes.add("build.scriptSourceDirectory"); translatedPrefixes.add("reporting.outputDirectory"); TRANSLATED_PATH_EXPRESSIONS = translatedPrefixes; } @Requirement private PathTranslator pathTranslator; private Interpolator interpolator; private RecursionInterceptor recursionInterceptor; // for testing. protected AbstractStringBasedModelInterpolator(PathTranslator pathTranslator) { this.pathTranslator = pathTranslator; } protected AbstractStringBasedModelInterpolator() { } public Model interpolate(Model model, Map<String, ?> context) throws ModelInterpolationException { return interpolate(model, context, true); } /** * Serialize the inbound Model instance to a StringWriter, perform the regex replacement to resolve * POM expressions, then re-parse into the resolved Model instance. * <p> * <b>NOTE:</b> This will result in a different instance of Model being returned!!! * * @param model The inbound Model instance, to serialize and reference for expression resolution * @param context The other context map to be used during resolution * * @return The resolved instance of the inbound Model. This is a different instance! * * @deprecated Use {@link ModelInterpolator#interpolate(Model, File, ProjectBuilderConfiguration, boolean)} instead. */ public Model interpolate(Model model, Map<String, ?> context, boolean strict) throws ModelInterpolationException { Properties props = new Properties(); props.putAll(context); return interpolate(model, null, new DefaultProjectBuilderConfiguration().setExecutionProperties(props), true); } public Model interpolate(Model model, File projectDir, ProjectBuilderConfiguration config, boolean debugEnabled) throws ModelInterpolationException { StringWriter sWriter = new StringWriter(1024); MavenXpp3Writer writer = new MavenXpp3Writer(); try { writer.write(sWriter, model); } catch (IOException e) { throw new ModelInterpolationException("Cannot serialize project model for interpolation.", e); } String serializedModel = sWriter.toString(); serializedModel = interpolate(serializedModel, model, projectDir, config, debugEnabled); StringReader sReader = new StringReader(serializedModel); MavenXpp3Reader modelReader = new MavenXpp3Reader(); try { model = modelReader.read(sReader); } catch (IOException | XmlPullParserException e) { throw new ModelInterpolationException( "Cannot read project model from interpolating filter of serialized version.", e); } return model; } /** * Interpolates all expressions in the src parameter. * <p> * The algorithm used for each expression is: * <ul> * <li>If it starts with either "pom." or "project.", the expression is evaluated against the model.</li> * <li>If the value is null, get the value from the context.</li> * <li>If the value is null, but the context contains the expression, don't replace the expression string * with the value, and continue to find other expressions.</li> * <li>If the value is null, get it from the model properties.</li> * </ul> */ public String interpolate(String src, Model model, final File projectDir, ProjectBuilderConfiguration config, boolean debug) throws ModelInterpolationException { try { List<ValueSource> valueSources = createValueSources(model, projectDir, config); List<InterpolationPostProcessor> postProcessors = createPostProcessors(model, projectDir, config); return interpolateInternal(src, valueSources, postProcessors, debug); } finally { interpolator.clearAnswers(); } } protected List<ValueSource> createValueSources(final Model model, final File projectDir, final ProjectBuilderConfiguration config) { String timestampFormat = DEFAULT_BUILD_TIMESTAMP_FORMAT; Properties modelProperties = model.getProperties(); if (modelProperties != null) { timestampFormat = modelProperties.getProperty(BUILD_TIMESTAMP_FORMAT_PROPERTY, timestampFormat); } ValueSource modelValueSource1 = new PrefixedObjectValueSource(PROJECT_PREFIXES, model, false); ValueSource modelValueSource2 = new ObjectBasedValueSource(model); ValueSource basedirValueSource = new PrefixedValueSourceWrapper(new AbstractValueSource(false) { public Object getValue(String expression) { if (projectDir != null && "basedir".equals(expression)) { return projectDir.getAbsolutePath(); } return null; } }, PROJECT_PREFIXES, true); ValueSource baseUriValueSource = new PrefixedValueSourceWrapper(new AbstractValueSource(false) { public Object getValue(String expression) { if (projectDir != null && "baseUri".equals(expression)) { return projectDir.getAbsoluteFile().toPath().toUri().toASCIIString(); } return null; } }, PROJECT_PREFIXES, false); List<ValueSource> valueSources = new ArrayList<>(9); // NOTE: Order counts here! valueSources.add(basedirValueSource); valueSources.add(baseUriValueSource); valueSources.add(new BuildTimestampValueSource(config.getBuildStartTime(), timestampFormat)); valueSources.add(modelValueSource1); valueSources.add(new MapBasedValueSource(config.getUserProperties())); valueSources.add(new MapBasedValueSource(modelProperties)); valueSources.add(new MapBasedValueSource(config.getExecutionProperties())); valueSources.add(new AbstractValueSource(false) { public Object getValue(String expression) { return config.getExecutionProperties().getProperty("env." + expression); } }); valueSources.add(modelValueSource2); return valueSources; } protected List<InterpolationPostProcessor> createPostProcessors(final Model model, final File projectDir, final ProjectBuilderConfiguration config) { return Collections .singletonList((InterpolationPostProcessor) new PathTranslatingPostProcessor(PROJECT_PREFIXES, TRANSLATED_PATH_EXPRESSIONS, projectDir, pathTranslator)); } @SuppressWarnings("unchecked") protected String interpolateInternal(String src, List<ValueSource> valueSources, List<InterpolationPostProcessor> postProcessors, boolean debug) throws ModelInterpolationException { if (!src.contains("${")) { return src; } Logger logger = getLogger(); String result = src; synchronized (this) { for (ValueSource vs : valueSources) { interpolator.addValueSource(vs); } for (InterpolationPostProcessor postProcessor : postProcessors) { interpolator.addPostProcessor(postProcessor); } try { try { result = interpolator.interpolate(result, recursionInterceptor); } catch (InterpolationException e) { throw new ModelInterpolationException(e.getMessage(), e); } if (debug) { List<Object> feedback = interpolator.getFeedback(); if (feedback != null && !feedback.isEmpty()) { logger.debug("Maven encountered the following problems during initial POM interpolation:"); Object last = null; for (Object next : feedback) { if (next instanceof Throwable) { if (last == null) { logger.debug("", ((Throwable) next)); } else { logger.debug(String.valueOf(last), ((Throwable) next)); } } else { if (last != null) { logger.debug(String.valueOf(last)); } last = next; } } if (last != null) { logger.debug(String.valueOf(last)); } } } interpolator.clearFeedback(); } finally { for (ValueSource vs : valueSources) { interpolator.removeValuesSource(vs); } for (InterpolationPostProcessor postProcessor : postProcessors) { interpolator.removePostProcessor(postProcessor); } } } return result; } protected RecursionInterceptor getRecursionInterceptor() { return recursionInterceptor; } protected void setRecursionInterceptor(RecursionInterceptor recursionInterceptor) { this.recursionInterceptor = recursionInterceptor; } protected abstract Interpolator createInterpolator(); public void initialize() throws InitializationException { interpolator = createInterpolator(); recursionInterceptor = new PrefixAwareRecursionInterceptor(PROJECT_PREFIXES); } protected final Interpolator getInterpolator() { return interpolator; } }