src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/NativeJavaPackage.java
changeset 47216 71c04702a3d5
parent 34447 ec4c069f9436
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/NativeJavaPackage.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,280 @@
+/*
+ * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.nashorn.internal.runtime;
+
+import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
+import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import jdk.dynalink.CallSiteDescriptor;
+import jdk.dynalink.beans.BeansLinker;
+import jdk.dynalink.beans.StaticClass;
+import jdk.dynalink.linker.GuardedInvocation;
+import jdk.dynalink.linker.LinkRequest;
+import jdk.dynalink.linker.support.Guards;
+import jdk.nashorn.internal.lookup.MethodHandleFactory;
+import jdk.nashorn.internal.lookup.MethodHandleFunctionality;
+import jdk.nashorn.internal.objects.annotations.Attribute;
+import jdk.nashorn.internal.objects.annotations.Function;
+import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;
+
+/**
+ * An object that exposes Java packages and classes as its properties. Packages are exposed as objects that have further
+ * sub-packages and classes as their properties. Normally, three instances of this class are exposed as built-in objects
+ * in Nashorn: {@code "Packages"}, {@code "java"}, and {@code "javax"}. Typical usages are:
+ * <pre>
+ * var list = new java.util.ArrayList()
+ * var sprocket = new Packages.com.acme.Sprocket()
+ * </pre>
+ * or you can store the type objects in a variable for later reuse:
+ * <pre>
+ * var ArrayList = java.util.ArrayList
+ * var list = new ArrayList
+ * </pre>
+ * You can also use {@link jdk.nashorn.internal.objects.NativeJava#type(Object, Object)} to access Java classes. These two statements are mostly
+ * equivalent:
+ * <pre>
+ * var listType1 = java.util.ArrayList
+ * var listType2 = Java.type("java.util.ArrayList")
+ * </pre>
+ * The difference is that {@code Java.type()} will throw an error if the class does not exist, while the first
+ * expression will return an empty object, as it must treat all non-existent classes as potentially being further
+ * subpackages. As such, {@code Java.type()} has the potential to catch typos earlier. A further difference is that
+ * {@code Java.type()} doesn't recognize {@code .} (dot) as the separator between outer class name and inner class name,
+ * it only recognizes the dollar sign. These are equivalent:
+ * <pre>
+ * var ftype1 = java.awt.geom.Arc2D$Float
+ * var ftype2 = java.awt.geom.Arc2D.Float
+ * var ftype3 = Java.asType("java.awt.geom.Arc2D$Float")
+ * var ftype4 = Java.asType("java.awt.geom.Arc2D").Float
+ * </pre>
+ */
+public final class NativeJavaPackage extends ScriptObject {
+    private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality();
+    private static final MethodHandle CLASS_NOT_FOUND = findOwnMH("classNotFound", Void.TYPE, NativeJavaPackage.class);
+    private static final MethodHandle TYPE_GUARD = Guards.getClassGuard(NativeJavaPackage.class);
+
+    /** Full name of package (includes path.) */
+    private final String name;
+
+    /**
+     * Public constructor to be accessible from {@link jdk.nashorn.internal.objects.Global}
+     * @param name  package name
+     * @param proto proto
+     */
+    public NativeJavaPackage(final String name, final ScriptObject proto) {
+        super(proto, null);
+        // defense-in-path, check here for sensitive packages
+        Context.checkPackageAccess(name);
+        this.name = name;
+    }
+
+    @Override
+    public String getClassName() {
+        return "JavaPackage";
+    }
+
+    @Override
+    public boolean equals(final Object other) {
+        if (other instanceof NativeJavaPackage) {
+            return name.equals(((NativeJavaPackage)other).name);
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return name == null ? 0 : name.hashCode();
+    }
+
+    /**
+     * Get the full name of the package
+     * @return the name
+     */
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String safeToString() {
+        return toString();
+    }
+
+    @Override
+    public String toString() {
+        return "[JavaPackage " + name + "]";
+    }
+
+    @Override
+    public Object getDefaultValue(final Class<?> hint) {
+        if (hint == String.class) {
+            return toString();
+        }
+
+        return super.getDefaultValue(hint);
+    }
+
+    @Override
+    protected GuardedInvocation findNewMethod(final CallSiteDescriptor desc, final LinkRequest request) {
+        return createClassNotFoundInvocation(desc);
+    }
+
+    @Override
+    protected GuardedInvocation findCallMethod(final CallSiteDescriptor desc, final LinkRequest request) {
+        return createClassNotFoundInvocation(desc);
+    }
+
+    private static GuardedInvocation createClassNotFoundInvocation(final CallSiteDescriptor desc) {
+        // If NativeJavaPackage is invoked either as a constructor or as a function, throw a ClassNotFoundException as
+        // we can assume the user attempted to instantiate a non-existent class.
+        final MethodType type = desc.getMethodType();
+        return new GuardedInvocation(
+                MH.dropArguments(CLASS_NOT_FOUND, 1, type.parameterList().subList(1, type.parameterCount())),
+                type.parameterType(0) == NativeJavaPackage.class ? null : TYPE_GUARD);
+    }
+
+    @SuppressWarnings("unused")
+    private static void classNotFound(final NativeJavaPackage pkg) throws ClassNotFoundException {
+        throw new ClassNotFoundException(pkg.name);
+    }
+
+    /**
+     * "No such property" call placeholder.
+     *
+     * This can never be called as we override {@link ScriptObject#noSuchProperty}. We do declare it here as it's a signal
+     * to {@link WithObject} that it's worth trying doing a {@code noSuchProperty} on this object.
+     *
+     * @param self self reference
+     * @param name property name
+     * @return never returns
+     */
+    @Function(attributes = Attribute.NOT_ENUMERABLE)
+    public static Object __noSuchProperty__(final Object self, final Object name) {
+        throw new AssertionError("__noSuchProperty__ placeholder called");
+    }
+
+    /**
+     * "No such method call" placeholder
+     *
+     * This can never be called as we override {@link ScriptObject#noSuchMethod}. We do declare it here as it's a signal
+     * to {@link WithObject} that it's worth trying doing a noSuchProperty on this object.
+     *
+     * @param self self reference
+     * @param args arguments to method
+     * @return never returns
+     */
+    @Function(attributes = Attribute.NOT_ENUMERABLE)
+    public static Object __noSuchMethod__(final Object self, final Object... args) {
+        throw new AssertionError("__noSuchMethod__ placeholder called");
+    }
+
+    /**
+     * Handle creation of new attribute.
+     * @param desc the call site descriptor
+     * @param request the link request
+     * @return Link to be invoked at call site.
+     */
+    @Override
+    public GuardedInvocation noSuchProperty(final CallSiteDescriptor desc, final LinkRequest request) {
+        final String propertyName = NashornCallSiteDescriptor.getOperand(desc);
+        createProperty(propertyName);
+        return super.lookup(desc, request);
+    }
+
+    @Override
+    protected Object invokeNoSuchProperty(final Object key, final boolean isScope, final int programPoint) {
+        if (!(key instanceof String)) {
+            return super.invokeNoSuchProperty(key, isScope, programPoint);
+        }
+        final Object retval = createProperty((String) key);
+        if (isValid(programPoint)) {
+            throw new UnwarrantedOptimismException(retval, programPoint);
+        }
+        return retval;
+    }
+
+    @Override
+    public GuardedInvocation noSuchMethod(final CallSiteDescriptor desc, final LinkRequest request) {
+        return noSuchProperty(desc, request);
+    }
+
+    private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
+        return MH.findStatic(MethodHandles.lookup(), NativeJavaPackage.class, name, MH.type(rtype, types));
+    }
+
+    private Object createProperty(final String propertyName) {
+        final String fullName     = name.isEmpty() ? propertyName : name + "." + propertyName;
+        final Context context = Context.getContextTrusted();
+
+        Class<?> javaClass = null;
+        try {
+            javaClass = context.findClass(fullName);
+        } catch (final NoClassDefFoundError | ClassNotFoundException e) {
+            //ignored
+        }
+
+        // Check for explicit constructor signature use
+        // Example: new (java.awt["Color(int, int,int)"])(2, 3, 4);
+        final int openBrace = propertyName.indexOf('(');
+        final int closeBrace = propertyName.lastIndexOf(')');
+        if (openBrace != -1 || closeBrace != -1) {
+            final int lastChar = propertyName.length() - 1;
+            if (openBrace == -1 || closeBrace != lastChar) {
+                throw typeError("improper.constructor.signature", propertyName);
+            }
+
+            // get the class name and try to load it
+            final String className = name + "." + propertyName.substring(0, openBrace);
+            try {
+                javaClass = context.findClass(className);
+            } catch (final NoClassDefFoundError | ClassNotFoundException e) {
+                throw typeError(e, "no.such.java.class", className);
+            }
+
+            // try to find a matching constructor
+            final Object constructor = BeansLinker.getConstructorMethod(
+                    javaClass, propertyName.substring(openBrace + 1, lastChar));
+            if (constructor != null) {
+                set(propertyName, constructor, 0);
+                return constructor;
+            }
+            // we didn't find a matching constructor!
+            throw typeError("no.such.java.constructor", propertyName);
+        }
+
+        final Object propertyValue;
+        if (javaClass == null) {
+            propertyValue = new NativeJavaPackage(fullName, getProto());
+        } else {
+            propertyValue = StaticClass.forClass(javaClass);
+        }
+
+        set(propertyName, propertyValue, 0);
+        return propertyValue;
+    }
+}