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package com.eg.google.gson.internal;

/*
 * Copyright (C) 2011 Google Inc.
 *
 * 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.
 */


import com.eg.google.gson.InstanceCreator;
import com.eg.google.gson.JsonIOException;
import com.eg.google.gson.reflect.TypeToken;

import org.gradle.internal.impldep.com.google.gson.internal.LinkedTreeMap;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.EnumSet;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;


/**
 * Returns a function that can construct an instance of a requested type.
 */
public final class ConstructorConstructor {
    private final Map> instanceCreators;

    public ConstructorConstructor(Map> instanceCreators) {
        this.instanceCreators = instanceCreators;
    }

    public  ObjectConstructor get(TypeToken typeToken) {
        final Type type = typeToken.getType();
        final Class rawType = typeToken.getRawType();

        // first try an instance creator

        @SuppressWarnings("unchecked") // types must agree
        final InstanceCreator typeCreator = (InstanceCreator) instanceCreators.get(type);
        if (typeCreator != null) {
            return new ObjectConstructor() {
                @Override public T construct() {
                    return typeCreator.createInstance(type);
                }
            };
        }

        // Next try raw type match for instance creators
        @SuppressWarnings("unchecked") // types must agree
        final InstanceCreator rawTypeCreator =
                (InstanceCreator) instanceCreators.get(rawType);
        if (rawTypeCreator != null) {
            return new ObjectConstructor() {
                @Override public T construct() {
                    return rawTypeCreator.createInstance(type);
                }
            };
        }

        ObjectConstructor defaultConstructor = newDefaultConstructor((Class) rawType);
        if (defaultConstructor != null) {
            return defaultConstructor;
        }

        ObjectConstructor defaultImplementation = newDefaultImplementationConstructor(type, (Class) rawType);
        if (defaultImplementation != null) {
            return defaultImplementation;
        }

        // finally try unsafe
        return newUnsafeAllocator(type, (Class) rawType);
    }

    private  ObjectConstructor newDefaultConstructor(Class rawType) {
        try {
            final Constructor constructor = rawType.getDeclaredConstructor();
            if (!constructor.isAccessible()) {
                constructor.setAccessible(true);
            }
            return new ObjectConstructor() {
                @SuppressWarnings("unchecked") // T is the same raw type as is requested
                @Override public T construct() {
                    try {
                        Object[] args = null;
                        return (T) constructor.newInstance(args);
                    } catch (InstantiationException e) {
                        // TODO: JsonParseException ?
                        throw new RuntimeException("Failed to invoke " + constructor + " with no args", e);
                    } catch (InvocationTargetException e) {
                        // TODO: don't wrap if cause is unchecked!
                        // TODO: JsonParseException ?
                        throw new RuntimeException("Failed to invoke " + constructor + " with no args",
                                e.getTargetException());
                    } catch (IllegalAccessException e) {
                        throw new AssertionError(e);
                    }
                }
            };
        } catch (NoSuchMethodException e) {
            return null;
        }
    }

    /**
     * Constructors for common interface types like Map and List and their
     * subtypes.
     */
    @SuppressWarnings("unchecked") // use runtime checks to guarantee that 'T' is what it is
    private  ObjectConstructor newDefaultImplementationConstructor(
            final Type type, Class rawType) {
        if (Collection.class.isAssignableFrom(rawType)) {
            if (SortedSet.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new TreeSet();
                    }
                };
            } else if (EnumSet.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @SuppressWarnings("rawtypes")
                    @Override public T construct() {
                        if (type instanceof ParameterizedType) {
                            Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0];
                            if (elementType instanceof Class) {
                                return (T) EnumSet.noneOf((Class)elementType);
                            } else {
                                throw new JsonIOException("Invalid EnumSet type: " + type.toString());
                            }
                        } else {
                            throw new JsonIOException("Invalid EnumSet type: " + type.toString());
                        }
                    }
                };
            } else if (Set.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new LinkedHashSet();
                    }
                };
            } else if (Queue.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new LinkedList();
                    }
                };
            } else {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new ArrayList();
                    }
                };
            }
        }

        if (Map.class.isAssignableFrom(rawType)) {
            if (ConcurrentNavigableMap.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new ConcurrentSkipListMap();
                    }
                };
            } else if (ConcurrentMap.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new ConcurrentHashMap();
                    }
                };
            } else if (SortedMap.class.isAssignableFrom(rawType)) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new TreeMap();
                    }
                };
            } else if (type instanceof ParameterizedType && !(String.class.isAssignableFrom(
                    TypeToken.get(((ParameterizedType) type).getActualTypeArguments()[0]).getRawType()))) {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new LinkedHashMap();
                    }
                };
            } else {
                return new ObjectConstructor() {
                    @Override public T construct() {
                        return (T) new LinkedTreeMap();
                    }
                };
            }
        }

        return null;
    }

    private  ObjectConstructor newUnsafeAllocator(
            final Type type, final Class rawType) {
        return new ObjectConstructor() {
            private final UnsafeAllocator unsafeAllocator = UnsafeAllocator.create();
            @SuppressWarnings("unchecked")
            @Override public T construct() {
                try {
                    Object newInstance = unsafeAllocator.newInstance(rawType);
                    return (T) newInstance;
                } catch (Exception e) {
                    throw new RuntimeException(("Unable to invoke no-args constructor for " + type + ". "
                            + "Register an InstanceCreator with Gson for this type may fix this problem."), e);
                }
            }
        };
    }

    @Override public String toString() {
        return instanceCreators.toString();
    }
}