net.sandius.rembulan.parser.ast.Attributes Maven / Gradle / Ivy
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/*
* Copyright 2016 Miroslav Janíček
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.sandius.rembulan.parser.ast;
import net.sandius.rembulan.util.Check;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
public final class Attributes {
private final Map, Object> attribs;
private static final Attributes EMPTY = new Attributes(Collections., Object>emptyMap());
private Attributes(Map, Object> attribs) {
this.attribs = Check.notNull(attribs);
}
public static Attributes empty() {
return EMPTY;
}
public static Attributes of(Object... objects) {
if (objects.length > 0) {
Map, Object> as = new HashMap<>();
for (Object o : objects) {
as.put(o.getClass(), o);
}
return new Attributes(Collections.unmodifiableMap(as));
}
else {
return empty();
}
}
public Attributes with(Object o) {
Check.notNull(o);
Class clazz = o.getClass();
if (Objects.equals(attribs.get(clazz), o)) {
return this;
}
else {
Map, Object> as = new HashMap<>();
as.putAll(attribs);
as.put(clazz, o);
return new Attributes(Collections.unmodifiableMap(as));
}
}
public T get(Class clazz) {
Check.notNull(clazz);
Object result = attribs.get(clazz);
if (result != null) {
if (clazz.isAssignableFrom(result.getClass())) {
@SuppressWarnings("unchecked")
T r = (T) result;
return r;
}
else {
throw new IllegalStateException("Illegal entry for " + clazz.getName());
}
}
else {
return null;
}
}
public boolean has(Class clazz) {
return get(clazz) != null;
}
}