diff --git a/java/jakarta/el/OptionalELResolver.java b/java/jakarta/el/OptionalELResolver.java
new file mode 100644
index 000000000000..6f9c3da73fec
--- /dev/null
+++ b/java/jakarta/el/OptionalELResolver.java
@@ -0,0 +1,182 @@
+/*
+ * 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 jakarta.el;
+
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * Defines property resolution behaviour on {@link Optional}s.
+ *
+ *
+ * This resolver handles base objects that are instances of {@link Optional}.
+ *
+ *
+ * If the {@link Optional#isEmpty()} is {@code true} for the base object and the property is {@code null} then the
+ * resulting value is {@code null}.
+ *
+ *
+ * If the {@link Optional#isEmpty()} is {@code true} for the base object and the property is not {@code null} then the
+ * resulting value is the base object (an empty {@link Optional}).
+ *
+ *
+ * If the {@link Optional#isPresent()} is {@code true} for the base object and the property is {@code null} then the
+ * resulting value is the result of calling {@link Optional#get()} on the base object.
+ *
+ *
+ * If the {@link Optional#isPresent()} is {@code true} for the base object and the property is not {@code null} then the
+ * resulting value is the result of calling {@link ELResolver#getValue(ELContext, Object, Object)} using the
+ * {@link ELResolver} obtained from {@link ELContext#getELResolver()} with the following parameters:
+ *
+ * - The {@link ELContext} is the current context
+ * - The base object is the result of calling {@link Optional#get()} on the current base object
-
+ *
- The property object is the current property object
+ *
+ *
+ *
+ * This resolver is always a read-only resolver.
+ */
+public class OptionalELResolver extends ELResolver {
+
+ @Override
+ public Object getValue(ELContext context, Object base, Object property) {
+ Objects.requireNonNull(context);
+
+ if (base instanceof Optional) {
+ context.setPropertyResolved(base, property);
+ if (((Optional>) base).isEmpty()) {
+ if (property == null) {
+ return null;
+ } else {
+ return base;
+ }
+ } else {
+ if (property == null) {
+ return ((Optional>) base).get();
+ } else {
+ Object resolvedBase = ((Optional>) base).get();
+ return context.getELResolver().getValue(context, resolvedBase, property);
+ }
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ *
+ * If the base object is an {@link Optional} this method always returns {@code null} since instances of this
+ * resolver are always read-only.
+ */
+ @Override
+ public Class> getType(ELContext context, Object base, Object property) {
+ Objects.requireNonNull(context);
+
+ if (base instanceof Optional) {
+ context.setPropertyResolved(base, property);
+ }
+
+ return null;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ *
+ * If the base object is an {@link Optional} this method always throws a {@link PropertyNotWritableException} since
+ * instances of this resolver are always read-only.
+ */
+ @Override
+ public void setValue(ELContext context, Object base, Object property, Object value) {
+ Objects.requireNonNull(context);
+
+ if (base instanceof Optional) {
+ throw new PropertyNotWritableException(
+ Util.message(context, "resolverNotWritable", base.getClass().getName()));
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ *
+ * If the base object is an {@link Optional} this method always returns {@code true} since instances of this
+ * resolver are always read-only.
+ */
+ @Override
+ public boolean isReadOnly(ELContext context, Object base, Object property) {
+ Objects.requireNonNull(context);
+
+ if (base instanceof Optional) {
+ context.setPropertyResolved(base, property);
+ return true;
+ }
+
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ *
+ * If the base object is an {@link Optional} this method always returns {@code Object.class}.
+ */
+ @Override
+ public Class> getCommonPropertyType(ELContext context, Object base) {
+ if (base instanceof Optional) {
+ return Object.class;
+ }
+
+ return null;
+ }
+
+ @Override
+ public T convertToType(ELContext context, Object obj, Class type) {
+ Objects.requireNonNull(context);
+ if (obj instanceof Optional) {
+ if (((Optional>) obj).isPresent()) {
+ Object value = ((Optional>) obj).get();
+ // If the value is assignable to the required type, do so.
+ if (type.isAssignableFrom(value.getClass())) {
+ context.setPropertyResolved(true);
+ @SuppressWarnings("unchecked")
+ T result = (T) value;
+ return result;
+ }
+
+ try {
+ Object convertedValue = context.convertToType(value, type);
+ context.setPropertyResolved(true);
+ @SuppressWarnings("unchecked")
+ T result = (T) convertedValue;
+ return result;
+ } catch (ELException e) {
+ /*
+ * TODO: This isn't pretty but it works. Significant refactoring would be required to avoid the
+ * exception. See also OptionalELResolver.convertToType().
+ */
+ }
+ } else {
+ context.setPropertyResolved(true);
+ return null;
+ }
+ }
+ return null;
+ }
+}
diff --git a/java/jakarta/el/Util.java b/java/jakarta/el/Util.java
index 168f89ce4211..f44b662063b4 100644
--- a/java/jakarta/el/Util.java
+++ b/java/jakarta/el/Util.java
@@ -493,8 +493,10 @@ static boolean isAssignableFrom(Class> src, Class> target) {
* This method duplicates code in org.apache.el.util.ReflectionUtil. When making changes keep the code in sync.
*/
private static boolean isCoercibleFrom(ELContext context, Object src, Class> target) {
- // TODO: This isn't pretty but it works. Significant refactoring would
- // be required to avoid the exception.
+ /*
+ * TODO: This isn't pretty but it works. Significant refactoring would be required to avoid the exception. See
+ * also OptionalELResolver.convertToType().
+ */
try {
context.convertToType(src, target);
} catch (ELException e) {
diff --git a/test/jakarta/el/TestOptionalELResolver.java b/test/jakarta/el/TestOptionalELResolver.java
new file mode 100644
index 000000000000..38b171d3f2ee
--- /dev/null
+++ b/test/jakarta/el/TestOptionalELResolver.java
@@ -0,0 +1,210 @@
+/*
+ * 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 jakarta.el;
+
+import java.util.Optional;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestOptionalELResolver {
+
+ @Test(expected = PropertyNotFoundException.class)
+ public void testIssue176WithoutOptionalResolverOptionalEmpty() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+
+ TesterBeanA beanA = new TesterBeanA();
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.name}", String.class);
+ ve.getValue(context);
+ }
+
+
+ @Test(expected = PropertyNotFoundException.class)
+ public void testIssue176WithoutOptionalResolverOptionalPresent() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+
+ TesterBeanA beanA = new TesterBeanA();
+ TesterBeanB beanB = new TesterBeanB("test");
+ beanA.setBeanB(beanB);
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.name}", String.class);
+ ve.getValue(context);
+ }
+
+
+ @Test
+ public void testIssue176WithOptionalResolverOptionalEmptyWithProperty() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+ context.addELResolver(new OptionalELResolver());
+
+ TesterBeanA beanA = new TesterBeanA();
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.name}", String.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertNull(result);
+ }
+
+
+ @Test
+ public void testIssue176WithOptionalResolverOptionalPresentWithProperty() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+ context.addELResolver(new OptionalELResolver());
+
+ TesterBeanA beanA = new TesterBeanA();
+ TesterBeanB beanB = new TesterBeanB("test");
+ beanA.setBeanB(beanB);
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.name}", String.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertEquals("test", result);
+ }
+
+
+ @Test
+ public void testIssue176WithOptionalResolverOptionalEmptyWithoutProperty() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+ context.addELResolver(new OptionalELResolver());
+
+ TesterBeanA beanA = new TesterBeanA();
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt}", TesterBeanB.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertNull(result);
+ }
+
+
+ @Test
+ public void testIssue176WithOptionalResolverOptionalPresentWithoutProperty() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+ context.addELResolver(new OptionalELResolver());
+
+ TesterBeanA beanA = new TesterBeanA();
+ TesterBeanB beanB = new TesterBeanB("test");
+ beanA.setBeanB(beanB);
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt}", TesterBeanB.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertEquals(beanB, result);
+ }
+
+
+ @Test
+ public void testIssue176WithoutOptionalResolverOptionalEmptyWithMap() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+
+ TesterBeanA beanA = new TesterBeanA();
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.map(b -> b.name)}", Optional.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertNotNull(result);
+ Assert.assertEquals(Optional.class, result.getClass());
+ Assert.assertTrue(((Optional>) result).isEmpty());
+ }
+
+
+ @Test
+ public void testIssue176WithoutOptionalResolverOptionalPresentWithMap() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+
+ TesterBeanA beanA = new TesterBeanA();
+ TesterBeanB beanB = new TesterBeanB("test");
+ beanA.setBeanB(beanB);
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.map(b -> b.name)}", Optional.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertNotNull(result);
+ Assert.assertEquals(Optional.class, result.getClass());
+ Assert.assertEquals("test", ((Optional>) result).get());
+ }
+
+
+ @Test
+ public void testIssue176WithOptionalResolverOptionalEmptyWithMap() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+ context.addELResolver(new OptionalELResolver());
+
+ TesterBeanA beanA = new TesterBeanA();
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.map(b -> b.name)}", String.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertNull(result);
+ }
+
+
+ @Test
+ public void testIssue176WithOptionalResolverOptionalPresentWithMap() {
+ ExpressionFactory factory = ExpressionFactory.newInstance();
+ StandardELContext context = new StandardELContext(factory);
+ context.addELResolver(new OptionalELResolver());
+
+ TesterBeanA beanA = new TesterBeanA();
+ TesterBeanB beanB = new TesterBeanB("test");
+ beanA.setBeanB(beanB);
+
+ ValueExpression varBeanA = factory.createValueExpression(beanA, TesterBeanA.class);
+ context.getVariableMapper().setVariable("beanA", varBeanA);
+
+ ValueExpression ve = factory.createValueExpression(context, "${beanA.beanBOpt.map(b -> b.name)}", String.class);
+ Object result = ve.getValue(context);
+
+ Assert.assertEquals("test", result);
+ }
+}
diff --git a/test/jakarta/el/TestOptionalELResolverInJsp.java b/test/jakarta/el/TestOptionalELResolverInJsp.java
new file mode 100644
index 000000000000..0b81fa3db04e
--- /dev/null
+++ b/test/jakarta/el/TestOptionalELResolverInJsp.java
@@ -0,0 +1,87 @@
+/*
+ * 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 jakarta.el;
+
+import java.io.File;
+
+import jakarta.servlet.ServletContext;
+import jakarta.servlet.ServletContextEvent;
+import jakarta.servlet.ServletContextListener;
+import jakarta.servlet.http.HttpServletResponse;
+import jakarta.servlet.jsp.JspApplicationContext;
+import jakarta.servlet.jsp.JspFactory;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import org.apache.catalina.Context;
+import org.apache.catalina.startup.Tomcat;
+import org.apache.catalina.startup.TomcatBaseTest;
+import org.apache.tomcat.util.buf.ByteChunk;
+
+
+public class TestOptionalELResolverInJsp extends TomcatBaseTest {
+
+ @Test
+ public void test() throws Exception {
+ Tomcat tomcat = getTomcatInstance();
+
+ File appDir = new File("test/webapp");
+ Context ctx = tomcat.addWebapp(null, "/test", appDir.getAbsolutePath());
+
+ ctx.addApplicationListener(ResolverConfigListener.class.getName());
+
+ tomcat.start();
+
+ ByteChunk responseBody = new ByteChunk();
+ int rc = getUrl("http://localhost:" + getPort() + "/test/el-optional.jsp", responseBody, null);
+
+ Assert.assertEquals(HttpServletResponse.SC_OK, rc);
+
+ String result = responseBody.toString();
+ assertEcho(result, "00-null");
+ assertEcho(result, "01-null");
+ assertEcho(result, "02-null");
+ assertEcho(result, "10-This is an instance of TesterBeanB");
+ assertEcho(result, "11-test");
+ assertEcho(result, "12-test");
+ assertEcho(result, "20-null");
+ assertEcho(result, "21-null");
+ assertEcho(result, "22-null");
+ assertEcho(result, "30-This is an instance of TesterBeanB");
+ assertEcho(result, "31-test");
+ assertEcho(result, "32-test");
+ }
+
+
+ // Assertion for text contained with , e.g. printed by tags:echo
+ private static void assertEcho(String result, String expected) {
+ Assert.assertTrue(result, result.indexOf("" + expected + "
") > 0);
+ }
+
+
+ public static class ResolverConfigListener implements ServletContextListener {
+
+ @Override
+ public void contextInitialized(ServletContextEvent sce) {
+ ServletContext servletContext = sce.getServletContext();
+ JspFactory jspFactory = JspFactory.getDefaultFactory();
+ JspApplicationContext jspApplicationContext = jspFactory.getJspApplicationContext(servletContext);
+ jspApplicationContext.addELResolver(new OptionalELResolver());
+ }
+ }
+}
diff --git a/test/jakarta/el/TesterBeanA.java b/test/jakarta/el/TesterBeanA.java
new file mode 100644
index 000000000000..97f153a4403d
--- /dev/null
+++ b/test/jakarta/el/TesterBeanA.java
@@ -0,0 +1,33 @@
+/*
+ * 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 jakarta.el;
+
+import java.util.Optional;
+
+public class TesterBeanA {
+ private TesterBeanB beanB;
+
+ public Optional getBeanBOpt() {
+ return Optional.ofNullable(beanB);
+ }
+
+ public void setBeanB(TesterBeanB beanB) {
+ this.beanB = beanB;
+ }
+}
+
+
diff --git a/test/jakarta/el/TesterBeanB.java b/test/jakarta/el/TesterBeanB.java
new file mode 100644
index 000000000000..66f9de0d4cdc
--- /dev/null
+++ b/test/jakarta/el/TesterBeanB.java
@@ -0,0 +1,35 @@
+/*
+ * 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 jakarta.el;
+
+public class TesterBeanB {
+
+ private final String name;
+
+ public TesterBeanB(String name) {
+ this.name = name;
+ }
+
+ public String getName() {
+ return name;
+ }
+
+ @Override
+ public String toString() {
+ return "This is an instance of TesterBeanB";
+ }
+}
diff --git a/test/webapp/el-optional.jsp b/test/webapp/el-optional.jsp
new file mode 100644
index 000000000000..8fcf3b919d2f
--- /dev/null
+++ b/test/webapp/el-optional.jsp
@@ -0,0 +1,48 @@
+<%--
+ 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.
+--%>
+<%@ taglib prefix="tags" tagdir="/WEB-INF/tags" %>
+<%@ page import="jakarta.el.TesterBeanA" %>
+<%@ page import="jakarta.el.TesterBeanB" %>
+
+ EL method test cases
+
+ <%
+ TesterBeanA beanA1 = new TesterBeanA();
+
+ TesterBeanA beanA2 = new TesterBeanA();
+ TesterBeanB beanB = new TesterBeanB("test");
+ beanA2.setBeanB(beanB);
+
+ pageContext.setAttribute("testBeanA1", beanA1, PageContext.REQUEST_SCOPE);
+ pageContext.setAttribute("testBeanA2", beanA2, PageContext.REQUEST_SCOPE);
+ %>
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 45dc7ce86cc7..6d58f1ceb270 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -135,6 +135,16 @@
+
+
+
+ Add java.util.Optional
support via the
+ jakarta.el.OptionalELResolver
to Tomcat's implementation
+ of the Jakarta EL API to align with the latest proposals for the Jakarta
+ EL 6.0 API. (markt)
+
+
+