com.google.gerrit.util.cli.OptionHandlers.java Source code

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Here is the source code for com.google.gerrit.util.cli.OptionHandlers.java

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// Copyright (C) 2013 The Android Open Source Project
//
// 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 com.google.gerrit.util.cli;

import com.google.common.collect.ImmutableMap;
import com.google.gerrit.common.Nullable;
import com.google.inject.Binding;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.Singleton;
import com.google.inject.TypeLiteral;
import java.lang.reflect.ParameterizedType;
import java.util.Map.Entry;

@Singleton
public class OptionHandlers {
    public static OptionHandlers empty() {
        ImmutableMap<Class<?>, Provider<OptionHandlerFactory<?>>> m = ImmutableMap.of();
        return new OptionHandlers(m);
    }

    private final ImmutableMap<Class<?>, Provider<OptionHandlerFactory<?>>> map;

    @Inject
    OptionHandlers(Injector parent) {
        this(build(parent));
    }

    OptionHandlers(ImmutableMap<Class<?>, Provider<OptionHandlerFactory<?>>> m) {
        this.map = m;
    }

    @Nullable
    OptionHandlerFactory<?> get(Class<?> type) {
        Provider<OptionHandlerFactory<?>> b = map.get(type);
        return b != null ? b.get() : null;
    }

    private static ImmutableMap<Class<?>, Provider<OptionHandlerFactory<?>>> build(Injector i) {
        ImmutableMap.Builder<Class<?>, Provider<OptionHandlerFactory<?>>> map = ImmutableMap.builder();
        for (; i != null; i = i.getParent()) {
            for (Entry<Key<?>, Binding<?>> e : i.getBindings().entrySet()) {
                TypeLiteral<?> type = e.getKey().getTypeLiteral();
                if (type.getRawType() == OptionHandlerFactory.class && e.getKey().getAnnotation() == null
                        && type.getType() instanceof ParameterizedType) {
                    map.put(getType(type), cast(e.getValue()).getProvider());
                }
            }
        }
        return map.build();
    }

    private static Class<?> getType(TypeLiteral<?> t) {
        ParameterizedType p = (ParameterizedType) t.getType();
        return (Class<?>) p.getActualTypeArguments()[0];
    }

    @SuppressWarnings("unchecked")
    private static Binding<OptionHandlerFactory<?>> cast(Binding<?> e) {
        return (Binding<OptionHandlerFactory<?>>) e;
    }
}