elharo commented on code in PR #1208:
URL: https://github.com/apache/maven/pull/1208#discussion_r1311520008


##########
maven-core/src/main/java/org/apache/maven/utils/dag/DAG.java:
##########
@@ -0,0 +1,240 @@
+/*
+ * 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.dag;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * DAG = Directed Acyclic Graph
+ *
+ * @author <a href="michal.mac...@dimatics.com">Michal Maczka</a>
+ *
+ * TODO this class should be renamed from DAG to Dag

Review Comment:
   Now is the time to do this



##########
maven-core/src/main/java/org/apache/maven/project/DefaultProjectBuilder.java:
##########
@@ -103,6 +102,10 @@ public class DefaultProjectBuilder implements 
ProjectBuilder {
 
     private final RootLocator rootLocator;
 
+    public static final String OS_NAME = 
System.getProperty("os.name").toLowerCase(Locale.US);

Review Comment:
   private



##########
maven-model-builder/src/main/java/org/apache/maven/utils/Os.java:
##########
@@ -0,0 +1,383 @@
+/*

Review Comment:
   This can't be copied over as is. It needs to be cleaned up and rethought. 
It's horribly out of date.



##########
maven-core/src/main/java/org/apache/maven/utils/dag/CycleDetectedException.java:
##########
@@ -0,0 +1,40 @@
+/*
+ * 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.dag;

Review Comment:
   This DAG stuff should probably be a separate PR from random StringUtils and 
IO fixes. 



##########
maven-model/src/main/java/org/apache/maven/model/io/xpp3/MavenXpp3ReaderEx.java:
##########
@@ -112,13 +119,13 @@ public Model read(InputStream in, InputSource source) 
throws IOException, XmlPul
      *
      * @param parser a parser object.
      * @param strict a strict object.
-     * @throws IOException IOException if any.
-     * @throws XmlPullParserException XmlPullParserException if
-     * any.
      * @return Model
+     * @throws IOException            IOException if any.

Review Comment:
   no period, and in general "if any" is not sufficient description. Something 
like "if an I/O error occurs while reading from the underlying source"



##########
maven-core/src/main/java/org/apache/maven/project/DefaultProjectBuilder.java:
##########
@@ -103,6 +102,10 @@ public class DefaultProjectBuilder implements 
ProjectBuilder {
 
     private final RootLocator rootLocator;
 
+    public static final String OS_NAME = 
System.getProperty("os.name").toLowerCase(Locale.US);
+
+    public static final String FAMILY_WINDOWS = "windows";

Review Comment:
   private
   
   In general, avoid introducing new public API



##########
maven-core/src/main/java/org/apache/maven/properties/internal/EnvironmentUtils.java:
##########
@@ -36,6 +34,10 @@ public class EnvironmentUtils {
 
     private static Properties envVars;
 
+    public static final String OS_NAME = 
System.getProperty("os.name").toLowerCase(Locale.US);

Review Comment:
   private



##########
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
+     * @throws Exception if any
+     */
+    public static Object evaluate(String expression, Object root) throws 
Exception {
+        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
+     * @throws Exception if any
+     */
+    // TODO: don't throw Exception
+    public static Object evaluate(String expression, final Object root, final 
boolean trimRootToken) throws Exception {
+        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)
+            throws Exception {
+        if (value == null || key == null) {
+            return null;
+        }
+
+        if (value instanceof Map) {
+            Object[] localParams = new Object[] {key};
+            ClassMap classMap = getClassMap(value.getClass());
+            Method method = classMap.findMethod("get", localParams);
+            return method.invoke(value, localParams);
+        }
+
+        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'",
+                expression.subSequence(from, to), from, value.getClass());
+
+        throw new Exception(message);

Review Comment:
   This should be a more specific exception.
   
   Note: I do not care if this was already done incorrectly somewhere else. 
It's still wrong here.



##########
maven-model/src/main/java/org/apache/maven/model/io/xpp3/MavenXpp3ReaderEx.java:
##########
@@ -54,56 +55,62 @@ public boolean getAddDefaultEntities() {
     /**
      * @param reader a reader object.
      * @param strict a strict object.
-     * @throws IOException IOException if any.
-     * @throws XmlPullParserException XmlPullParserException if
-     * any.
      * @return Model
+     * @throws IOException            IOException if any.
+     * @throws XMLStreamException XMLStreamException if
+     *                                any.
      */
-    public Model read(Reader reader, boolean strict, InputSource source) 
throws IOException, XmlPullParserException {
-        XmlPullParser parser =
-                addDefaultEntities ? new 
MXParser(EntityReplacementMap.defaultEntityReplacementMap) : new MXParser();
-        parser.setInput(reader);
+    public Model read(Reader reader, boolean strict, InputSource source) 
throws IOException, XMLStreamException {
+        XMLInputFactory factory = new com.ctc.wstx.stax.WstxInputFactory();
+        factory.setProperty(XMLInputFactory.IS_REPLACING_ENTITY_REFERENCES, 
false);
+        XMLStreamReader parser = null;

Review Comment:
   try block needs to surround everything



##########
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
+     * @throws Exception if any
+     */
+    public static Object evaluate(String expression, Object root) throws 
Exception {
+        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
+     * @throws Exception if any
+     */
+    // TODO: don't throw Exception
+    public static Object evaluate(String expression, final Object root, final 
boolean trimRootToken) throws Exception {
+        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)
+            throws Exception {
+        if (value == null || key == null) {
+            return null;
+        }
+
+        if (value instanceof Map) {
+            Object[] localParams = new Object[] {key};
+            ClassMap classMap = getClassMap(value.getClass());
+            Method method = classMap.findMethod("get", localParams);
+            return method.invoke(value, localParams);
+        }
+
+        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'",
+                expression.subSequence(from, to), from, value.getClass());
+
+        throw new Exception(message);
+    }
+
+    private static Object getIndexedValue(
+            final String expression, final int from, final int to, final 
Object value, final String indexStr)
+            throws Exception {
+        try {
+            int index = Integer.parseInt(indexStr);

Review Comment:
   indexStr should probably be an int



##########
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
+     * @throws Exception if any
+     */
+    public static Object evaluate(String expression, Object root) throws 
Exception {
+        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
+     * @throws Exception if any
+     */
+    // TODO: don't throw Exception
+    public static Object evaluate(String expression, final Object root, final 
boolean trimRootToken) throws Exception {
+        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)
+            throws Exception {
+        if (value == null || key == null) {
+            return null;
+        }
+
+        if (value instanceof Map) {
+            Object[] localParams = new Object[] {key};
+            ClassMap classMap = getClassMap(value.getClass());
+            Method method = classMap.findMethod("get", localParams);
+            return method.invoke(value, localParams);
+        }
+
+        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'",
+                expression.subSequence(from, to), from, value.getClass());
+
+        throw new Exception(message);
+    }
+
+    private static Object getIndexedValue(
+            final String expression, final int from, final int to, final 
Object value, final String indexStr)
+            throws Exception {
+        try {
+            int index = Integer.parseInt(indexStr);
+
+            if (value.getClass().isArray()) {
+                return Array.get(value, index);
+            }
+
+            if (value instanceof List) {
+                ClassMap classMap = getClassMap(value.getClass());
+                // use get method on List interface
+                Object[] localParams = new Object[] {index};
+                Method method = classMap.findMethod("get", localParams);
+                return method.invoke(value, localParams);
+            }
+        } catch (NumberFormatException e) {
+            return null;

Review Comment:
   This seems very suspicious



##########
maven-model/src/main/java/org/apache/maven/model/io/xpp3/MavenXpp3ReaderEx.java:
##########
@@ -112,13 +119,13 @@ public Model read(InputStream in, InputSource source) 
throws IOException, XmlPul
      *
      * @param parser a parser object.
      * @param strict a strict object.
-     * @throws IOException IOException if any.
-     * @throws XmlPullParserException XmlPullParserException if
-     * any.
      * @return Model
+     * @throws IOException            IOException if any.
+     * @throws XMLStreamException XMLStreamException if

Review Comment:
   definitely needs to be expanded and distinguished from IOException



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