2 * Copyright (c) 2016 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.yangtools.yang.parser.stmt.reactor;
10 import static com.google.common.base.Preconditions.checkArgument;
11 import static com.google.common.base.Verify.verify;
12 import static java.util.Objects.requireNonNull;
14 import com.google.common.collect.AbstractIterator;
15 import com.google.common.collect.Iterators;
16 import java.util.AbstractCollection;
17 import java.util.Arrays;
18 import java.util.Collection;
19 import java.util.Iterator;
20 import java.util.function.Consumer;
21 import org.eclipse.jdt.annotation.NonNull;
22 import org.eclipse.jdt.annotation.Nullable;
25 * Simple integer-to-StatementContextBase map optimized for size and restricted in scope of operations. It does not
26 * implement {@link java.util.Map} for simplicity's sake.
29 * Unlike other collections, this view does not detect concurrent modification. Iteration is performed in order of
30 * increasing offset. In face of concurrent modification, number of elements returned through iteration may not match
31 * the size reported via {@link Collection#size()}.
33 * @author Robert Varga
35 abstract class StatementMap extends AbstractCollection<AbstractResumedStatement<?, ?, ?>> {
36 private static final class Empty extends StatementMap {
37 private static final Iterator<AbstractResumedStatement<?, ?, ?>> EMPTY_ITERATOR;
40 // This may look weird, but we really want to return two Iterator implementations from StatementMap, so that
41 // users have to deal with bimorphic invocation. Note that we want to invoke hasNext() here, as we want to
42 // initialize state to AbstractIterator.endOfData().
43 final Iterator<AbstractResumedStatement<?, ?, ?>> it = new Regular(0).iterator();
44 verify(!it.hasNext());
49 AbstractResumedStatement<?, ?, ?> get(final int index) {
54 StatementMap put(final int index, final AbstractResumedStatement<?, ?, ?> obj) {
55 return index == 0 ? new Singleton(obj) : new Regular(index, obj);
64 StatementMap ensureCapacity(final int expectedLimit) {
65 return expectedLimit < 2 ? this : new Regular(expectedLimit);
69 public void forEach(final Consumer<? super AbstractResumedStatement<?, ?, ?>> action) {
74 public Iterator<AbstractResumedStatement<?, ?, ?>> iterator() {
75 return EMPTY_ITERATOR;
79 private static final class Regular extends StatementMap {
80 private AbstractResumedStatement<?, ?, ?>[] elements;
83 Regular(final int expectedLimit) {
84 elements = new AbstractResumedStatement<?, ?, ?>[expectedLimit];
87 Regular(final int index, final AbstractResumedStatement<?, ?, ?> object) {
88 this(index + 1, index, object);
91 Regular(final AbstractResumedStatement<?, ?, ?> object0, final int index,
92 final AbstractResumedStatement<?, ?, ?> object) {
93 this(index + 1, 0, object0);
94 elements[index] = requireNonNull(object);
98 Regular(final int expectedLimit, final int index, final AbstractResumedStatement<?, ?, ?> object) {
100 elements[index] = requireNonNull(object);
105 AbstractResumedStatement<?, ?, ?> get(final int index) {
106 return index >= elements.length ? null : elements[index];
110 StatementMap put(final int index, final AbstractResumedStatement<?, ?, ?> obj) {
111 if (index < elements.length) {
112 checkArgument(elements[index] == null);
114 // FIXME: detect linear growth
115 elements = Arrays.copyOf(elements, index + 1);
118 elements[index] = requireNonNull(obj);
129 StatementMap ensureCapacity(final int expectedLimit) {
130 if (elements.length < expectedLimit) {
131 elements = Arrays.copyOf(elements, expectedLimit);
137 public Iterator<AbstractResumedStatement<?, ?, ?>> iterator() {
138 return new AbstractIterator<>() {
139 private int nextOffset = 0;
142 protected AbstractResumedStatement<?, ?, ?> computeNext() {
143 while (nextOffset < elements.length) {
144 final AbstractResumedStatement<?, ?, ?> ret = elements[nextOffset++];
156 private static final class Singleton extends StatementMap {
157 private final AbstractResumedStatement<?, ?, ?> object;
159 Singleton(final AbstractResumedStatement<?, ?, ?> object) {
160 this.object = requireNonNull(object);
164 AbstractResumedStatement<?, ?, ?> get(final int index) {
165 return index == 0 ? object : null;
169 StatementMap put(final int index, final AbstractResumedStatement<?, ?, ?> obj) {
170 checkArgument(index != 0);
171 return new Regular(this.object, index, obj);
180 StatementMap ensureCapacity(final int expectedLimit) {
181 return expectedLimit < 2 ? this : new Regular(expectedLimit, 0, object);
185 public Iterator<AbstractResumedStatement<?, ?, ?>> iterator() {
186 return Iterators.singletonIterator(object);
190 private static final StatementMap EMPTY = new Empty();
192 static StatementMap empty() {
197 * Return the statement context at specified index.
199 * @param index Element index, must be non-negative
200 * @return Requested element or null if there is no element at that index
202 abstract @Nullable AbstractResumedStatement<?, ?, ?> get(int index);
205 * Add a statement at specified index.
207 * @param index Element index, must be non-negative
208 * @param obj Object to store
209 * @return New statement map
210 * @throws IllegalArgumentException if the index is already occupied
212 abstract @NonNull StatementMap put(int index, @NonNull AbstractResumedStatement<?, ?, ?> obj);
214 abstract @NonNull StatementMap ensureCapacity(int expectedLimit);