/*
* Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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.
*
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package java.lang.invoke;
import static java.lang.invoke.MethodHandleStatics.*;
import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
/**
* Unary function composition, useful for many small plumbing jobs.
* The invoke method takes a single reference argument, and returns a reference
* Internally, it first calls the {@code filter} method on the argument,
* Making up the difference between the raw method type and the
* final method type is the responsibility of a JVM-level adapter.
* @author jrose
*/
class FilterOneArgument extends BoundMethodHandle {
protected final MethodHandle filter; // Object -> Object
protected final MethodHandle target; // Object -> Object
@Override
String debugString() {
return target.toString();
}
protected Object invoke(Object argument) throws Throwable {
Object filteredArgument = filter.invokeExact(argument);
return target.invokeExact(filteredArgument);
}
private static final MethodHandle INVOKE;
static {
try {
INVOKE =
IMPL_LOOKUP.findVirtual(FilterOneArgument.class, "invoke",
MethodType.genericMethodType(1));
} catch (ReflectiveOperationException ex) {
throw uncaughtException(ex);
}
}
protected FilterOneArgument(MethodHandle filter, MethodHandle target) {
super(INVOKE);
this.filter = filter;
this.target = target;
}
static {
assert(MethodHandleNatives.workaroundWithoutRicochetFrames()); // this class is deprecated
}
public static MethodHandle make(MethodHandle filter, MethodHandle target) {
if (filter == null) return target;
if (target == null) return filter;
return new FilterOneArgument(filter, target);
}
// MethodHandle make(MethodHandle filter1, MethodHandle filter2, MethodHandle target) {
// MethodHandle filter = make(filter1, filter2);
// return make(filter, target);
// }
}