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DSL Platform compatible Java JSON library (https://dsl-platform.com)

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package com.dslplatform.json.runtime;

import com.dslplatform.json.*;

import java.io.IOException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.*;
import java.util.concurrent.Callable;

public abstract class CollectionAnalyzer {

	public static class Runtime {
		public static final JsonReader.ReadObject> JSON_READER = new JsonReader.ReadObject>() {
			@Override
			public List read(JsonReader reader) throws IOException {
				if (reader.wasNull()) return null;
				return ObjectConverter.deserializeList(reader);
			}
		};
		public static final JsonWriter.WriteObject> JSON_WRITER = new JsonWriter.WriteObject>() {
			@Override
			public void write(JsonWriter writer, @Nullable List value) {
				if (value == null) {
					writer.writeNull();
				} else if (value.isEmpty()) {
					writer.writeAscii("[]");
				} else if (value instanceof RandomAccess) {
					writer.writeByte(JsonWriter.ARRAY_START);
					writer.serializeObject(value.get(0));
					for(int i = 1; i < value.size(); i++) {
						writer.writeByte(JsonWriter.COMMA);
						writer.serializeObject(value.get(i));
					}
					writer.writeByte(JsonWriter.ARRAY_END);
				} else {
					writer.writeByte(JsonWriter.ARRAY_START);
					Iterator iter = value.iterator();
					writer.serializeObject(iter.next());
					while (iter.hasNext()) {
						writer.writeByte(JsonWriter.COMMA);
						writer.serializeObject(iter.next());
					}
					writer.writeByte(JsonWriter.ARRAY_END);
				}
			}
		};
	}

	public static final DslJson.ConverterFactory READER = new DslJson.ConverterFactory() {
		@Nullable
		@Override
		public CollectionDecoder tryCreate(Type manifest, DslJson dslJson) {
			if (manifest instanceof Class) {
				return analyzeDecoding(manifest, Object.class, (Class) manifest, dslJson);
			}
			if (manifest instanceof ParameterizedType) {
				final ParameterizedType pt = (ParameterizedType) manifest;
				if (pt.getActualTypeArguments().length == 1) {
					return analyzeDecoding(manifest, pt.getActualTypeArguments()[0], (Class) pt.getRawType(), dslJson);
				}
			}
			return null;
		}
	};

	public static final DslJson.ConverterFactory WRITER = new DslJson.ConverterFactory() {
		@Nullable
		@Override
		public CollectionEncoder tryCreate(Type manifest, DslJson dslJson) {
			if (manifest instanceof Class) {
				return analyzeEncoding(manifest, Object.class, (Class) manifest, dslJson);
			}
			if (manifest instanceof ParameterizedType) {
				final ParameterizedType pt = (ParameterizedType) manifest;
				if (pt.getActualTypeArguments().length == 1) {
					return analyzeEncoding(manifest, pt.getActualTypeArguments()[0], (Class) pt.getRawType(), dslJson);
				}
			}
			return null;
		}
	};

	@Nullable
	private static CollectionDecoder analyzeDecoding(final Type manifest, final Type element, final Class collection, final DslJson json) {
		if (!Collection.class.isAssignableFrom(collection)) return null;
		final Callable newInstance;
		if (!collection.isInterface()) {
			try {
				collection.newInstance();
			} catch (Exception ex) {
				return null;
			}
			newInstance = new Callable() {
				@Override
				public Object call() throws Exception {
					return collection.newInstance();
				}
			};
		} else if (Set.class.isAssignableFrom(collection)) {
			newInstance = new Callable() {
				@Override
				public Object call() {
					return new LinkedHashSet<>(4);
				}
			};
		} else if (List.class.isAssignableFrom(collection) || Collection.class == collection) {
			newInstance = new Callable() {
				@Override
				public Object call() throws Exception {
					return new ArrayList<>(4);
				}
			};
		} else if (Queue.class.isAssignableFrom(collection)) {
			newInstance = new Callable() {
				@Override
				public Object call() throws Exception {
					return new LinkedList();
				}
			};
		} else {
			return null;
		}
		final JsonReader.ReadObject reader = json.tryFindReader(element);
		if (reader == null) {
			return null;
		}
		final CollectionDecoder decoder = new CollectionDecoder<>(manifest, newInstance, reader);
		json.registerReader(manifest, decoder);
		return decoder;
	}

	@Nullable
	private static CollectionEncoder analyzeEncoding(final Type manifest, final Type element, final Class collection, final DslJson json) {
		if (!Collection.class.isAssignableFrom(collection)) return null;
		final JsonWriter.WriteObject writer = Object.class == element ? null : json.tryFindWriter(element);
		if (Object.class != element && writer == null) {
			return null;
		}
		final CollectionEncoder encoder = new CollectionEncoder<>(json, Settings.isKnownType(element) ? writer : null);
		json.registerWriter(manifest, encoder);
		return encoder;
	}
}
    

    

    

            

    

            



    
    






    
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