1 /* 2 * Copyright (c) 2008, 2010, 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 sun.dyn; 27 28 import java.dyn.*; 29 import static sun.dyn.MemberName.uncaughtException; 30 31 /** 32 * Unary function composition, useful for many small plumbing jobs. 33 * The invoke method takes a single reference argument, and returns a reference 34 * Internally, it first calls the {@code filter} method on the argument, 35 * Making up the difference between the raw method type and the 36 * final method type is the responsibility of a JVM-level adapter. 37 * @author jrose 38 */ 39 public class FilterOneArgument extends BoundMethodHandle { 40 protected final MethodHandle filter; // Object -> Object 41 protected final MethodHandle target; // Object -> Object 42 43 @Override 44 public String toString() { 45 return target.toString(); 46 } 47 48 protected Object invoke(Object argument) throws Throwable { 49 Object filteredArgument = filter.invokeExact(argument); 50 return target.invokeExact(filteredArgument); 51 } 52 53 private static final MethodHandle INVOKE; 54 static { 55 try { 56 INVOKE = 57 MethodHandleImpl.IMPL_LOOKUP.findVirtual(FilterOneArgument.class, "invoke", 58 MethodType.genericMethodType(1)); 59 } catch (NoAccessException ex) { 60 throw uncaughtException(ex); 61 } 62 } 63 64 protected FilterOneArgument(MethodHandle filter, MethodHandle target) { 65 super(Access.TOKEN, INVOKE); 66 this.filter = filter; 67 this.target = target; 68 } 69 70 public static MethodHandle make(MethodHandle filter, MethodHandle target) { 71 if (filter == null) return target; 72 if (target == null) return filter; 73 return new FilterOneArgument(filter, target); 74 } 75 76 // MethodHandle make(MethodHandle filter1, MethodHandle filter2, MethodHandle target) { 77 // MethodHandle filter = make(filter1, filter2); 78 // return make(filter, target); 79 // } 80 }