--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/lang/invoke/AbstractConstantGroup.java Fri Sep 08 10:46:46 2017 -0700
@@ -0,0 +1,341 @@
+/*
+ * Copyright (c) 2017, 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 java.lang.invoke;
+
+import java.util.*;
+import jdk.internal.vm.annotation.Stable;
+
+import static java.lang.invoke.MethodHandleStatics.rangeCheck1;
+import static java.lang.invoke.MethodHandleStatics.rangeCheck2;
+
+/** Utility class for implementing ConstantGroup. */
+/*non-public*/
+abstract class AbstractConstantGroup implements ConstantGroup {
+ /** The size of this constant group, set permanently by the constructor. */
+ protected final int size;
+
+ /** The constructor requires the size of the constant group being represented.
+ * @param size the size of this constant group, set permanently by the constructor
+ */
+ AbstractConstantGroup(int size) {
+ this.size = size;
+ }
+
+ @Override public final int size() {
+ return size;
+ }
+
+ public abstract Object get(int index) throws LinkageError;
+
+ public abstract Object get(int index, Object ifNotPresent);
+
+ public abstract boolean isPresent(int index);
+
+ // Do not override equals or hashCode, since this type is stateful.
+
+ /**
+ * Produce a string using the non-resolving list view,
+ * where unresolved elements are presented as asterisks.
+ * @return {@code this.asList("*").toString()}
+ */
+ @Override public String toString() {
+ return asList("*").toString();
+ }
+
+ static class AsIterator implements Iterator<Object> {
+ private final ConstantGroup self;
+ private final int end;
+ private final boolean resolving;
+ private final Object ifNotPresent;
+
+ // Mutable state:
+ private int index;
+
+ private AsIterator(ConstantGroup self, int start, int end,
+ boolean resolving, Object ifNotPresent) {
+ this.self = self;
+ this.end = end;
+ this.index = start;
+ this.resolving = resolving;
+ this.ifNotPresent = ifNotPresent;
+ }
+ AsIterator(ConstantGroup self, int start, int end) {
+ this(self, start, end, true, null);
+ }
+ AsIterator(ConstantGroup self, int start, int end,
+ Object ifNotPresent) {
+ this(self, start, end, false, ifNotPresent);
+ }
+
+ @Override
+ public boolean hasNext() {
+ return index < end;
+ }
+
+ @Override
+ public Object next() {
+ int i = bumpIndex();
+ if (resolving)
+ return self.get(i);
+ else
+ return self.get(i, ifNotPresent);
+ }
+
+ private int bumpIndex() {
+ int i = index;
+ if (i >= end) throw new NoSuchElementException();
+ index = i+1;
+ return i;
+ }
+ }
+
+ static class SubGroup extends AbstractConstantGroup {
+ private final ConstantGroup self; // the real CG
+ private final int offset; // offset within myself
+ SubGroup(ConstantGroup self, int start, int end) {
+ super(end - start);
+ this.self = self;
+ this.offset = start;
+ rangeCheck2(start, end, size);
+ }
+
+ private int mapIndex(int index) {
+ return rangeCheck1(index, size) + offset;
+ }
+
+ @Override
+ public Object get(int index) {
+ return self.get(mapIndex(index));
+ }
+
+ @Override
+ public Object get(int index, Object ifNotPresent) {
+ return self.get(mapIndex(index), ifNotPresent);
+ }
+
+ @Override
+ public boolean isPresent(int index) {
+ return self.isPresent(mapIndex(index));
+ }
+
+ @Override
+ public ConstantGroup subGroup(int start, int end) {
+ rangeCheck2(start, end, size);
+ return new SubGroup(self, offset + start, offset + end);
+ }
+
+ @Override
+ public List<Object> asList() {
+ return new AsList(self, offset, offset + size);
+ }
+
+ @Override
+ public List<Object> asList(Object ifNotPresent) {
+ return new AsList(self, offset, offset + size, ifNotPresent);
+ }
+
+ @Override
+ public int copyConstants(int start, int end,
+ Object[] buf, int pos) throws LinkageError {
+ rangeCheck2(start, end, size);
+ return self.copyConstants(offset + start, offset + end,
+ buf, pos);
+ }
+
+ @Override
+ public int copyConstants(int start, int end,
+ Object[] buf, int pos,
+ Object ifNotPresent) {
+ rangeCheck2(start, end, size);
+ return self.copyConstants(offset + start, offset + end,
+ buf, pos, ifNotPresent);
+ }
+ }
+
+ static class AsList extends AbstractList<Object> {
+ private final ConstantGroup self;
+ private final int size;
+ private final int offset;
+ private final boolean resolving;
+ private final Object ifNotPresent;
+
+ private AsList(ConstantGroup self, int start, int end,
+ boolean resolving, Object ifNotPresent) {
+ this.self = self;
+ this.size = end - start;
+ this.offset = start;
+ this.resolving = resolving;
+ this.ifNotPresent = ifNotPresent;
+ rangeCheck2(start, end, self.size());
+ }
+ AsList(ConstantGroup self, int start, int end) {
+ this(self, start, end, true, null);
+ }
+ AsList(ConstantGroup self, int start, int end,
+ Object ifNotPresent) {
+ this(self, start, end, false, ifNotPresent);
+ }
+
+ private int mapIndex(int index) {
+ return rangeCheck1(index, size) + offset;
+ }
+
+ @Override public final int size() {
+ return size;
+ }
+
+ @Override public Object get(int index) {
+ if (resolving)
+ return self.get(mapIndex(index));
+ else
+ return self.get(mapIndex(index), ifNotPresent);
+ }
+
+ @Override
+ public Iterator<Object> iterator() {
+ if (resolving)
+ return new AsIterator(self, offset, offset + size);
+ else
+ return new AsIterator(self, offset, offset + size, ifNotPresent);
+ }
+
+ @Override public List<Object> subList(int start, int end) {
+ rangeCheck2(start, end, size);
+ return new AsList(self, offset + start, offset + end,
+ resolving, ifNotPresent);
+ }
+
+ @Override public Object[] toArray() {
+ return toArray(new Object[size]);
+ }
+ @Override public <T> T[] toArray(T[] a) {
+ int pad = a.length - size;
+ if (pad < 0) {
+ pad = 0;
+ a = Arrays.copyOf(a, size);
+ }
+ if (resolving)
+ self.copyConstants(offset, offset + size, a, 0);
+ else
+ self.copyConstants(offset, offset + size, a, 0,
+ ifNotPresent);
+ if (pad > 0) a[size] = null;
+ return a;
+ }
+ }
+
+ static abstract
+ class WithCache extends AbstractConstantGroup {
+ @Stable final Object[] cache;
+
+ WithCache(int size) {
+ super(size);
+ // It is caller's responsibility to initialize the cache.
+ // Initial contents are all-null, which means nothing is present.
+ cache = new Object[size];
+ }
+
+ void initializeCache(List<Object> cacheContents, Object ifNotPresent) {
+ // Replace ifNotPresent with NOT_PRESENT,
+ // and null with RESOLVED_TO_NULL.
+ // Then forget about the user-provided ifNotPresent.
+ for (int i = 0; i < cache.length; i++) {
+ Object x = cacheContents.get(i);
+ if (x == ifNotPresent)
+ continue; // leave the null in place
+ if (x == null)
+ x = RESOLVED_TO_NULL;
+ cache[i] = x;
+ }
+ }
+
+ @Override public Object get(int i) {
+ Object x = cache[i];
+ // @Stable array must use null for sentinel
+ if (x == null) x = fillCache(i);
+ return unwrapNull(x);
+ }
+
+ @Override public Object get(int i, Object ifNotAvailable) {
+ Object x = cache[i];
+ // @Stable array must use null for sentinel
+ if (x == null) return ifNotAvailable;
+ return unwrapNull(x);
+ }
+
+ @Override
+ public boolean isPresent(int i) {
+ return cache[i] != null;
+ }
+
+ /** hook for local subclasses */
+ Object fillCache(int i) {
+ throw new NoSuchElementException("constant group does not contain element #"+i);
+ }
+
+ /// routines for mapping between null sentinel and true resolved null
+
+ static Object wrapNull(Object x) {
+ return x == null ? RESOLVED_TO_NULL : x;
+ }
+
+ static Object unwrapNull(Object x) {
+ assert(x != null);
+ return x == RESOLVED_TO_NULL ? null : x;
+ }
+
+ // secret sentinel for an actual null resolved value, in the cache
+ static final Object RESOLVED_TO_NULL = new Object();
+
+ // secret sentinel for a "hole" in the cache:
+ static final Object NOT_PRESENT = new Object();
+
+ }
+
+ /** Skeleton implementation of BootstrapCallInfo. */
+ static
+ class BSCIWithCache<T> extends WithCache implements BootstrapCallInfo<T> {
+ private final MethodHandle bsm;
+ private final String name;
+ private final T type;
+
+ @Override public String toString() {
+ return bsm+"/"+name+":"+type+super.toString();
+ }
+
+ BSCIWithCache(MethodHandle bsm, String name, T type, int size) {
+ super(size);
+ this.type = type;
+ this.bsm = bsm;
+ this.name = name;
+ assert(type instanceof Class || type instanceof MethodType);
+ }
+
+ @Override public MethodHandle bootstrapMethod() { return bsm; }
+ @Override public String invocationName() { return name; }
+ @Override public T invocationType() { return type; }
+ }
+}