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jdk/src/java.base/share/classes/java/lang/StackTraceElement.java
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@@ -23,11 +23,22 @@
* questions.
*/
package java.lang;
+import jdk.internal.loader.BuiltinClassLoader;
+import jdk.internal.misc.SharedSecrets;
+import jdk.internal.misc.VM;
+import jdk.internal.module.ModuleHashes;
+
+import java.lang.module.ModuleDescriptor.Version;
+import java.lang.reflect.Layer;
+import java.lang.reflect.Module;
+import java.util.HashSet;
import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
/**
* An element in a stack trace, as returned by {@link
* Throwable#getStackTrace()}. Each element represents a single stack frame.
* All stack frames except for the one at the top of the stack represent
@@ -38,11 +49,19 @@
*
* @since 1.4
* @author Josh Bloch
*/
public final class StackTraceElement implements java.io.Serializable {
- // Normally initialized by VM (public constructor added in 1.5)
+ // This field is set to the compacted String representation used
+ // by StackTraceElement::toString and stored in serial form.
+ //
+ // This field is of Object type. VM initially sets this field to
+ // the Class object of the declaring class to build the compacted string.
+ private Object classOrLoaderModuleClassName;
+
+ // Normally initialized by VM
+ private String classLoaderName;
private String moduleName;
private String moduleVersion;
private String declaringClass;
private String methodName;
private String fileName;
@@ -70,23 +89,26 @@
* {@code methodName} is null
* @since 1.5
*/
public StackTraceElement(String declaringClass, String methodName,
String fileName, int lineNumber) {
- this(null, null, declaringClass, methodName, fileName, lineNumber);
+ this(null, null, null, declaringClass, methodName, fileName, lineNumber);
}
/**
* Creates a stack trace element representing the specified execution
* point.
*
+ * @param classLoaderName the class loader name if the class loader of
+ * the class containing the execution point represented by
+ * the stack trace is named; otherwise {@code null}
* @param moduleName the module name if the class containing the
* execution point represented by the stack trace is in a named
- * module; can be {@code null}
+ * module; otherwise {@code null}
* @param moduleVersion the module version if the class containing the
* execution point represented by the stack trace is in a named
- * module that has a version; can be {@code null}
+ * module that has a version; otherwise {@code null}
* @param declaringClass the fully qualified name of the class containing
* the execution point represented by the stack trace element
* @param methodName the name of the method containing the execution point
* represented by the stack trace element
* @param fileName the name of the file containing the execution point
@@ -95,30 +117,44 @@
* @param lineNumber the line number of the source line containing the
* execution point represented by this stack trace element, or
* a negative number if this information is unavailable. A value
* of -2 indicates that the method containing the execution point
* is a native method
+ *
+ * @throws IllegalArgumentException if {@code classLoaderName},
+ * {@code moduleName} or {@code moduleVersion} is an empty string
* @throws NullPointerException if {@code declaringClass} is {@code null}
* or {@code methodName} is {@code null}
+ *
* @since 9
*/
- public StackTraceElement(String moduleName, String moduleVersion,
+ public StackTraceElement(String classLoaderName,
+ String moduleName, String moduleVersion,
String declaringClass, String methodName,
String fileName, int lineNumber) {
- this.moduleName = moduleName;
- this.moduleVersion = moduleVersion;
+ this.classLoaderName = requireNonEmpty(classLoaderName, "classLoaderName");
+ this.moduleName = requireNonEmpty(moduleName, "moduleName");
+ this.moduleVersion = requireNonEmpty(moduleVersion, "moduleVersion");
this.declaringClass = Objects.requireNonNull(declaringClass, "Declaring class is null");
this.methodName = Objects.requireNonNull(methodName, "Method name is null");
this.fileName = fileName;
this.lineNumber = lineNumber;
}
+ private static String requireNonEmpty(String name, String paramName) {
+ if (name != null && name.isEmpty()) {
+ throw new IllegalArgumentException(paramName +
+ " must be non-empty or null");
+ }
+ return name;
+ }
- /**
- * Creates an empty stack frame element to be filled in by Throwable.
+ /*
+ * Private constructor for the factory methods to create StackTraceElement
+ * for Throwable and StackFrameInfo
*/
- StackTraceElement() { }
+ private StackTraceElement() {}
/**
* Returns the name of the source file containing the execution point
* represented by this stack trace element. Generally, this corresponds
* to the {@code SourceFile} attribute of the relevant {@code class}
@@ -176,10 +212,25 @@
public String getModuleVersion() {
return moduleVersion;
}
/**
+ * Returns the name of the class loader of the class containing the
+ * execution point represented by this stack trace element.
+ *
+ * @return the name of the class loader of the class containing the execution
+ * point represented by this stack trace element; {@code null}
+ * if the class loader is not named.
+ *
+ * @since 9
+ * @see java.lang.ClassLoader#getName()
+ */
+ public String getClassLoaderName() {
+ return classLoaderName;
+ }
+
+ /**
* Returns the fully qualified name of the class containing the
* execution point represented by this stack trace element.
*
* @return the fully qualified name of the {@code Class} containing
* the execution point represented by this stack trace element.
@@ -218,42 +269,86 @@
* Returns a string representation of this stack trace element. The
* format of this string depends on the implementation, but the following
* examples may be regarded as typical:
* <ul>
* <li>
- * {@code "MyClass.mash(my.module@9.0/MyClass.java:101)"} - Here,
- * {@code "MyClass"} is the <i>fully-qualified name</i> of the class
- * containing the execution point represented by this stack trace element,
- * {@code "mash"} is the name of the method containing the execution
- * point, {@code "my.module"} is the module name, {@code "9.0"} is the
- * module version, and {@code "101"} is the line number of the source
- * line containing the execution point.
+ * "{@code com.foo.loader/foo@9.0/com.foo.Main.run(Main.java:101)}"
+ * - See the description below.
+ * </li>
* <li>
- * {@code "MyClass.mash(my.module@9.0/MyClass.java)"} - As above, but the
- * line number is unavailable.
+ * "{@code com.foo.loader/foo@9.0/com.foo.Main.run(Main.java)}"
+ * - The line number is unavailable.
+ * </li>
* <li>
- * {@code "MyClass.mash(my.module@9.0/Unknown Source)"} - As above, but
- * neither the file name nor the line number are available.
+ * "{@code com.foo.loader/foo@9.0/com.foo.Main.run(Unknown Source)}"
+ * - Neither the file name nor the line number is available.
+ * </li>
* <li>
- * {@code "MyClass.mash(my.module@9.0/Native Method)"} - As above, but
- * neither the file name nor the line number are available, and the
- * method containing the execution point is known to be a native method.
+ * "{@code com.foo.loader/foo@9.0/com.foo.Main.run(Native Method)}"
+ * - The method containing the execution point is a native method.
+ * </li>
+ * <li>
+ * "{@code com.foo.loader//com.foo.bar.App.run(App.java:12)}"
+ * - The class of the execution point is defined in the unnamed module of
+ * the class loader named {@code com.foo.loader}.
+ * </li>
+ * <li>
+ * "{@code acme@2.1/org.acme.Lib.test(Lib.java:80)}"
+ * - The class of the execution point is defined in {@code acme} module
+ * loaded by by a built-in class loader such as the application class loader.
+ * </li>
+ * <li>
+ * "{@code MyClass.mash(MyClass.java:9)}"
+ * - {@code MyClass} class is on the application class path.
+ * </li>
* </ul>
- * If the execution point is not in a named module, {@code "my.module@9.0/"}
- * will be omitted from the above.
+ *
+ * <p> The first example shows a stack trace element consisting of
+ * three elements, each separated by {@code "/"} followed with
+ * the source file name and the line number of the source line
+ * containing the execution point.
+ *
+ * The first element "{@code com.foo.loader}" is
+ * the name of the class loader. The second element "{@code foo@9.0}"
+ * is the module name and version. The third element is the method
+ * containing the execution point; "{@code com.foo.Main"}" is the
+ * fully-qualified class name and "{@code run}" is the name of the method.
+ * "{@code Main.java}" is the source file name and "{@code 101}" is
+ * the line number.
+ *
+ * <p> If a class is defined in an <em>unnamed module</em>
+ * then the second element is omitted as shown in
+ * "{@code com.foo.loader//com.foo.bar.App.run(App.java:12)}".
+ *
+ * If the class loader is a <a href="ClassLoader.html#builtinLoaders">
+ * built-in class loader</a> or is not named then the first element
+ * and its following {@code "/"} are omitted as shown in
+ * "{@code acme@2.1/org.acme.Lib.test(Lib.java:80)}".
+ * If the first element is omitted and the module is an unnamed module,
+ * the second element and its following {@code "/"} are also omitted
+ * as shown in "{@code MyClass.mash(MyClass.java:9)}".
*
* @see Throwable#printStackTrace()
*/
public String toString() {
- String mid = "";
- if (moduleName != null) {
- mid = moduleName;
- if (moduleVersion != null)
- mid += "@" + moduleVersion;
- mid += "/";
+ String s = buildLoaderModuleClassName();
+ if (s == null) {
+ // all elements will be included
+ s = "";
+ if (classLoaderName != null && !classLoaderName.isEmpty()) {
+ s += classLoaderName + "/";
+ }
+ if (moduleName != null && !moduleName.isEmpty()) {
+ s += moduleName;
+ }
+ if (moduleVersion != null && !moduleVersion.isEmpty()) {
+ s += "@" + moduleVersion;
+ }
+ s = s.isEmpty() ? declaringClass : s + "/" + declaringClass;
}
- return getClassName() + "." + methodName + "(" + mid +
+
+ return s + "." + methodName + "(" +
(isNativeMethod() ? "Native Method)" :
(fileName != null && lineNumber >= 0 ?
fileName + ":" + lineNumber + ")" :
(fileName != null ? ""+fileName+")" : "Unknown Source)")));
}
@@ -262,16 +357,18 @@
* Returns true if the specified object is another
* {@code StackTraceElement} instance representing the same execution
* point as this instance. Two stack trace elements {@code a} and
* {@code b} are equal if and only if:
* <pre>{@code
- * equals(a.getFileName(), b.getFileName()) &&
- * a.getLineNumber() == b.getLineNumber()) &&
+ * equals(a.getClassLoaderName(), b.getClassLoaderName()) &&
* equals(a.getModuleName(), b.getModuleName()) &&
* equals(a.getModuleVersion(), b.getModuleVersion()) &&
* equals(a.getClassName(), b.getClassName()) &&
* equals(a.getMethodName(), b.getMethodName())
+ * equals(a.getFileName(), b.getFileName()) &&
+ * a.getLineNumber() == b.getLineNumber()
+ *
* }</pre>
* where {@code equals} has the semantics of {@link
* java.util.Objects#equals(Object, Object) Objects.equals}.
*
* @param obj the object to be compared with this stack trace element.
@@ -283,27 +380,178 @@
if (obj==this)
return true;
if (!(obj instanceof StackTraceElement))
return false;
StackTraceElement e = (StackTraceElement)obj;
- return e.declaringClass.equals(declaringClass) &&
+ return Objects.equals(classLoaderName, e.classLoaderName) &&
Objects.equals(moduleName, e.moduleName) &&
Objects.equals(moduleVersion, e.moduleVersion) &&
+ e.declaringClass.equals(declaringClass) &&
e.lineNumber == lineNumber &&
Objects.equals(methodName, e.methodName) &&
Objects.equals(fileName, e.fileName);
}
/**
* Returns a hash code value for this stack trace element.
*/
public int hashCode() {
int result = 31*declaringClass.hashCode() + methodName.hashCode();
+ result = 31*result + Objects.hashCode(classLoaderName);
result = 31*result + Objects.hashCode(moduleName);
result = 31*result + Objects.hashCode(moduleVersion);
result = 31*result + Objects.hashCode(fileName);
result = 31*result + lineNumber;
return result;
}
+
+ /**
+ * Build the compacted String representation to be returned by
+ * toString method from the declaring Class object.
+ */
+ synchronized String buildLoaderModuleClassName() {
+ if (classOrLoaderModuleClassName == null)
+ return null;
+
+ if (classOrLoaderModuleClassName instanceof Class) {
+ Class<?> cls = (Class<?>)classOrLoaderModuleClassName;
+ classOrLoaderModuleClassName = toLoaderModuleClassName(cls);
+ }
+ return (String)classOrLoaderModuleClassName;
+ }
+
+ /**
+ * Returns <loader>/<module>/<fully-qualified-classname> string
+ * representation of the given class.
+ * <p>
+ * If the module is a non-upgradeable JDK module then omit
+ * its version string.
+ * <p>
+ * If the loader has no name, or if the loader is one of the built-in
+ * loaders (`boot`, `platform`, or `app`) then drop the first element
+ * (`<loader>/`).
+ * <p>
+ * If the first element has been dropped and the module is unnamed
+ * then drop the second element (`<module>/`).
+ * <p>
+ * If the first element is not dropped and the module is unnamed
+ * then drop `<module>`.
+ */
+ private static String toLoaderModuleClassName(Class<?> cls) {
+ ClassLoader loader = cls.getClassLoader0();
+ Module m = cls.getModule();
+
+ // First element - class loader name
+ // Call package-private ClassLoader::name method
+ String s = "";
+ if (loader != null && loader.name() != null &&
+ !(loader instanceof BuiltinClassLoader)) {
+ s = loader.name() + "/";
+ }
+
+ // Second element - module name and version
+ if (m != null && m.isNamed()) {
+ s += m.getName();
+ // Include version if it is a user module or upgradeable module
+ //
+ // If it is JDK non-upgradeable module which is recorded
+ // in the hashes in java.base, omit the version.
+ if (!isHashedInJavaBase(m)) {
+ Optional<Version> ov = m.getDescriptor().version();
+ if (ov.isPresent()) {
+ String version = "@" + ov.get().toString();
+ s += version;
+ }
+ }
+ }
+
+ // fully-qualified class name
+ return s.isEmpty() ? cls.getName() : s + "/" + cls.getName();
+ }
+
+ /**
+ * Returns true if the module is hashed with java.base.
+ * <p>
+ * This method returns false when running on the exploded image
+ * since JDK modules are not hashed. They have no Version attribute
+ * and so "@<version>" part will be omitted anyway.
+ */
+ private static boolean isHashedInJavaBase(Module m) {
+ // return true if module system is not initialized as the code
+ // must be in java.base
+ if (!VM.isModuleSystemInited())
+ return true;
+
+ return Layer.boot() == m.getLayer() && HashedModules.contains(m);
+ }
+
+ /*
+ * Finds JDK non-upgradeable modules, i.e. the modules that are
+ * included in the hashes in java.base.
+ */
+ private static class HashedModules {
+ static Set<String> HASHED_MODULES = hashedModules();
+
+ static Set<String> hashedModules() {
+ Module javaBase = Layer.boot().findModule("java.base").get();
+ Optional<ModuleHashes> ohashes =
+ SharedSecrets.getJavaLangModuleAccess()
+ .hashes(javaBase.getDescriptor());
+
+ if (ohashes.isPresent()) {
+ Set<String> names = new HashSet<>(ohashes.get().names());
+ names.add("java.base");
+ return names;
+ }
+
+ return Set.of();
+ }
+
+ static boolean contains(Module m) {
+ return HASHED_MODULES.contains(m.getName());
+ }
+ }
+
+
+ /*
+ * Returns a StackTraceElement from a given StackFrameInfo.
+ */
+ static StackTraceElement of(StackFrameInfo sfi) {
+ StackTraceElement ste = new StackTraceElement();
+ ste.fillFromStackFrameInfo(sfi);
+ ste.buildLoaderModuleClassName();
+ return ste;
+ }
+
+ /*
+ * Returns an array of StackTraceElements of the given depth
+ * filled from the backtrace of a given Throwable.
+ */
+ static StackTraceElement[] of(Throwable x, int depth) {
+ StackTraceElement[] stackTrace = new StackTraceElement[depth];
+ for (int i = 0; i < depth; i++) {
+ stackTrace[i] = new StackTraceElement();
+ }
+
+ // VM to fill in StackTraceElement
+ fillStackTraceFromThrowable(stackTrace, x);
+
+ // ensure the proper StackTraceElement initialization
+ for (StackTraceElement ste : stackTrace) {
+ ste.buildLoaderModuleClassName();
+ }
+ return stackTrace;
+ }
+
+ /*
+ * Fill in the stack trace elements from a given Throwable.
+ */
+ private static native void fillStackTraceFromThrowable(StackTraceElement[] elements,
+ Throwable x);
+ /*
+ * Fill in the stack trace elements from a given StackFrameInfo.
+ */
+ private native void fillFromStackFrameInfo(StackFrameInfo sfi);
+
private static final long serialVersionUID = 6992337162326171013L;
}
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