1 /* 2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.nashorn.api.scripting; 27 28 import jdk.nashorn.internal.runtime.JSType; 29 30 /** 31 * Default implementation of {@link JSObject#getDefaultValue(Class)}. Isolated into a separate class mostly so 32 * that we can have private static instances of function name arrays, something we couldn't declare without it 33 * being visible in {@link JSObject} interface. 34 */ 35 class DefaultValueImpl { 36 private static final String[] DEFAULT_VALUE_FNS_NUMBER = new String[] { "valueOf", "toString" }; 37 private static final String[] DEFAULT_VALUE_FNS_STRING = new String[] { "toString", "valueOf" }; 38 39 static Object getDefaultValue(final JSObject jsobj, final Class<?> hint) throws UnsupportedOperationException { 40 final boolean isNumber = hint == null || hint == Number.class; 41 for(final String methodName: isNumber ? DEFAULT_VALUE_FNS_NUMBER : DEFAULT_VALUE_FNS_STRING) { 42 final Object objMember = jsobj.getMember(methodName); 43 if (objMember instanceof JSObject) { 44 final JSObject member = (JSObject)objMember; 45 if (member.isFunction()) { 46 final Object value = member.call(jsobj); 47 if (JSType.isPrimitive(value)) { 48 return value; 49 } 50 } 51 } 52 } 53 throw new UnsupportedOperationException(isNumber ? "cannot.get.default.number" : "cannot.get.default.string"); 54 } 55 }