io.airlift.json.JsonCodecFactory.java Source code

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Here is the source code for io.airlift.json.JsonCodecFactory.java

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/*
 * Copyright 2010 Proofpoint, 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.
 */
package io.airlift.json;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Preconditions;
import com.google.common.reflect.TypeParameter;
import com.google.common.reflect.TypeToken;

import javax.inject.Inject;
import javax.inject.Provider;

import java.lang.reflect.Type;
import java.util.List;
import java.util.Map;

import static com.fasterxml.jackson.databind.SerializationFeature.INDENT_OUTPUT;

public class JsonCodecFactory {
    private final Provider<ObjectMapper> objectMapperProvider;
    private final boolean prettyPrint;

    public JsonCodecFactory() {
        this(new ObjectMapperProvider());
    }

    @Inject
    public JsonCodecFactory(Provider<ObjectMapper> objectMapperProvider) {
        this(objectMapperProvider, false);
    }

    public JsonCodecFactory(Provider<ObjectMapper> objectMapperProvider, boolean prettyPrint) {
        this.objectMapperProvider = objectMapperProvider;
        this.prettyPrint = prettyPrint;
    }

    public JsonCodecFactory prettyPrint() {
        return new JsonCodecFactory(objectMapperProvider, true);
    }

    public <T> JsonCodec<T> jsonCodec(Class<T> type) {
        Preconditions.checkNotNull(type, "type is null");

        return new JsonCodec<>(createObjectMapper(), type);
    }

    public <T> JsonCodec<T> jsonCodec(Type type) {
        Preconditions.checkNotNull(type, "type is null");

        return new JsonCodec<>(createObjectMapper(), type);
    }

    public <T> JsonCodec<T> jsonCodec(TypeToken<T> type) {
        Preconditions.checkNotNull(type, "type is null");

        return new JsonCodec<>(createObjectMapper(), type.getType());
    }

    public <T> JsonCodec<List<T>> listJsonCodec(Class<T> type) {
        Preconditions.checkNotNull(type, "type is null");

        Type listType = new TypeToken<List<T>>() {
        }.where(new TypeParameter<T>() {
        }, type).getType();

        return new JsonCodec<>(createObjectMapper(), listType);
    }

    public <T> JsonCodec<List<T>> listJsonCodec(JsonCodec<T> type) {
        Preconditions.checkNotNull(type, "type is null");

        Type listType = new TypeToken<List<T>>() {
        }.where(new TypeParameter<T>() {
        }, type.getTypeToken()).getType();

        return new JsonCodec<>(createObjectMapper(), listType);
    }

    public <K, V> JsonCodec<Map<K, V>> mapJsonCodec(Class<K> keyType, Class<V> valueType) {
        Preconditions.checkNotNull(keyType, "keyType is null");
        Preconditions.checkNotNull(valueType, "valueType is null");

        Type mapType = new TypeToken<Map<K, V>>() {
        }.where(new TypeParameter<K>() {
        }, keyType).where(new TypeParameter<V>() {
        }, valueType).getType();

        return new JsonCodec<>(createObjectMapper(), mapType);
    }

    public <K, V> JsonCodec<Map<K, V>> mapJsonCodec(Class<K> keyType, JsonCodec<V> valueType) {
        Preconditions.checkNotNull(keyType, "keyType is null");
        Preconditions.checkNotNull(valueType, "valueType is null");

        Type mapType = new TypeToken<Map<K, V>>() {
        }.where(new TypeParameter<K>() {
        }, keyType).where(new TypeParameter<V>() {
        }, valueType.getTypeToken()).getType();

        return new JsonCodec<>(createObjectMapper(), mapType);
    }

    private ObjectMapper createObjectMapper() {
        ObjectMapper objectMapper = null;

        // Work around for http://code.google.com/p/google-guice/issues/detail?id=627
        RuntimeException lastException = null;
        for (int i = 0; objectMapper == null && i < 10; i++) {
            try {
                objectMapper = objectMapperProvider.get();
            } catch (RuntimeException e) {
                lastException = e;
            }
        }
        if (objectMapper == null) {
            throw lastException;
        }

        if (prettyPrint) {
            objectMapper.enable(INDENT_OUTPUT);
        } else {
            objectMapper.disable(INDENT_OUTPUT);
        }
        return objectMapper;
    }
}