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https://issues.apache.org/jira/browse/MNG-7820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17764411#comment-17764411
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ASF GitHub Bot commented on MNG-7820:
-------------------------------------
gnodet commented on code in PR #1208:
URL: https://github.com/apache/maven/pull/1208#discussion_r1323636017
##########
maven-core/src/main/java/org/apache/maven/utils/introspection/ReflectionValueExtractor.java:
##########
@@ -0,0 +1,325 @@
+/*
+ * 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.
+ */
+package org.apache.maven.utils.introspection;
+
+import java.lang.ref.WeakReference;
+import java.lang.reflect.Array;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.Map;
+import java.util.WeakHashMap;
+
+/**
+ * <p>
+ * Using simple dotted expressions to extract the values from an Object
instance, For example we might want to extract a
+ * value like: <code>project.build.sourceDirectory</code>
+ * </p>
+ * <p>
+ * The implementation supports indexed, nested and mapped properties similar
to the JSP way.
+ * </p>
+ *
+ * @author <a href="mailto:ja...@maven.org";>Jason van Zyl </a>
+ * @author <a href="mailto:vincent.sive...@gmail.com";>Vincent Siveton</a>
+ *
+ * @see <a href=
+ *
"http://struts.apache.org/1.x/struts-taglib/indexedprops.html";>http://struts.apache.org/1.x/struts-taglib/indexedprops.html</a>
+ */
+public class ReflectionValueExtractor {
+ private static final Class<?>[] CLASS_ARGS = new Class[0];
+
+ private static final Object[] OBJECT_ARGS = new Object[0];
+
+ /**
+ * Use a WeakHashMap here, so the keys (Class objects) can be garbage
collected. This approach prevents permgen
+ * space overflows due to retention of discarded classloaders.
+ */
+ private static final Map<Class<?>, WeakReference<ClassMap>> CLASS_MAPS =
new WeakHashMap<>();
+
+ static final int EOF = -1;
+
+ static final char PROPERTY_START = '.';
+
+ static final char INDEXED_START = '[';
+
+ static final char INDEXED_END = ']';
+
+ static final char MAPPED_START = '(';
+
+ static final char MAPPED_END = ')';
+
+ static class Tokenizer {
+ final String expression;
+
+ int idx;
+
+ Tokenizer(String expression) {
+ this.expression = expression;
+ }
+
+ public int peekChar() {
+ return idx < expression.length() ? expression.charAt(idx) : EOF;
+ }
+
+ public int skipChar() {
+ return idx < expression.length() ? expression.charAt(idx++) : EOF;
+ }
+
+ public String nextToken(char delimiter) {
+ int start = idx;
+
+ while (idx < expression.length() && delimiter !=
expression.charAt(idx)) {
+ idx++;
+ }
+
+ // delimiter MUST be present
+ if (idx <= start || idx >= expression.length()) {
+ return null;
+ }
+
+ return expression.substring(start, idx++);
+ }
+
+ public String nextPropertyName() {
+ final int start = idx;
+
+ while (idx < expression.length() &&
Character.isJavaIdentifierPart(expression.charAt(idx))) {
+ idx++;
+ }
+
+ // property name does not require delimiter
+ if (idx <= start || idx > expression.length()) {
+ return null;
+ }
+
+ return expression.substring(start, idx);
+ }
+
+ public int getPosition() {
+ return idx < expression.length() ? idx : EOF;
+ }
+
+ // to make tokenizer look pretty in debugger
+ @Override
+ public String toString() {
+ return idx < expression.length() ? expression.substring(idx) :
"<EOF>";
+ }
+ }
+
+ private ReflectionValueExtractor() {}
+
+ /**
+ * <p>The implementation supports indexed, nested and mapped
properties.</p>
+ *
+ * <ul>
+ * <li>nested properties should be defined by a dot, i.e.
"user.address.street"</li>
+ * <li>indexed properties (java.util.List or array instance) should be
contains <code>(\\w+)\\[(\\d+)\\]</code>
+ * pattern, i.e. "user.addresses[1].street"</li>
+ * <li>mapped properties should be contains <code>(\\w+)\\((.+)\\)</code>
pattern, i.e.
+ * "user.addresses(myAddress).street"</li>
+ * </ul>
+ *
+ * @param expression not null expression
+ * @param root not null object
+ * @return the object defined by the expression
+ */
+ public static Object evaluate(String expression, Object root) {
+ return evaluate(expression, root, true);
+ }
+
+ /**
+ * <p>The implementation supports indexed, nested and mapped
properties.</p>
+ *
+ * <ul>
+ * <li>nested properties should be defined by a dot, i.e.
"user.address.street"</li>
+ * <li>indexed properties (java.util.List or array instance) should be
contains <code>(\\w+)\\[(\\d+)\\]</code>
+ * pattern, i.e. "user.addresses[1].street"</li>
+ * <li>mapped properties should be contains <code>(\\w+)\\((.+)\\)</code>
pattern, i.e.
+ * "user.addresses(myAddress).street"</li>
+ * </ul>
+ *
+ * @param expression not null expression
+ * @param root not null object
+ * @param trimRootToken root start
+ * @return the object defined by the expression
+ */
+ public static Object evaluate(String expression, final Object root, final
boolean trimRootToken) {
+ Object value = root;
+
+ //
----------------------------------------------------------------------
+ // Walk the dots and retrieve the ultimate value desired from the
+ // MavenProject instance.
+ //
----------------------------------------------------------------------
+
+ if (expression == null || expression.isEmpty() ||
!Character.isJavaIdentifierStart(expression.charAt(0))) {
+ return null;
+ }
+
+ boolean hasDots = expression.indexOf(PROPERTY_START) >= 0;
+
+ final Tokenizer tokenizer;
+ if (trimRootToken && hasDots) {
+ tokenizer = new Tokenizer(expression);
+ tokenizer.nextPropertyName();
+ if (tokenizer.getPosition() == EOF) {
+ return null;
+ }
+ } else {
+ tokenizer = new Tokenizer("." + expression);
+ }
+
+ int propertyPosition = tokenizer.getPosition();
+ while (value != null && tokenizer.peekChar() != EOF) {
+ switch (tokenizer.skipChar()) {
+ case INDEXED_START:
+ value = getIndexedValue(
+ expression,
+ propertyPosition,
+ tokenizer.getPosition(),
+ value,
+ tokenizer.nextToken(INDEXED_END));
+ break;
+ case MAPPED_START:
+ value = getMappedValue(
+ expression,
+ propertyPosition,
+ tokenizer.getPosition(),
+ value,
+ tokenizer.nextToken(MAPPED_END));
+ break;
+ case PROPERTY_START:
+ propertyPosition = tokenizer.getPosition();
+ value = getPropertyValue(value,
tokenizer.nextPropertyName());
+ break;
+ default:
+ // could not parse expression
+ return null;
+ }
+ }
+
+ return value;
+ }
+
+ private static Object getMappedValue(
+ final String expression, final int from, final int to, final
Object value, final String key) {
+ if (value == null || key == null) {
+ return null;
+ }
+ if (value instanceof Map) {
+ try {
+ Object[] localParams = new Object[] {key};
+ ClassMap classMap = getClassMap(value.getClass());
+ Method method = classMap.findMethod("get", localParams);
+ return method.invoke(value, localParams);
+ } catch (Exception e) {
+ throw new RuntimeException(e);
+ }
+ } else {
+ final String message = String.format(
+ "The token '%s' at position '%d' refers to a
java.util.Map, but the value seems is an instance of '%s'",
Review Comment:
I've removed the `seems` ...
> Remove dependency on plexus-utils
> ---------------------------------
>
> Key: MNG-7820
> URL: https://issues.apache.org/jira/browse/MNG-7820
> Project: Maven
> Issue Type: Task
> Reporter: Guillaume Nodet
> Priority: Major
> Fix For: 4.0.0-alpha-8
>
>
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