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DTO streaming
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down-port eclipse-che/che#3103

Change-Id: Iea2704e625105ad483ee9f1348b217b0bc493d6e
Signed-off-by: Tareq Sharafy <tareq.sha@gmail.com>
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@tareksha
tareksha committed Feb 13, 2017
1 parent 78efd43 commit 693320f
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Showing 9 changed files with 197 additions and 375 deletions.
14 changes: 14 additions & 0 deletions platform-api/che-core-api-dto/src/main/java/org/eclipse/che/dto/generator/DtoImpl.java
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Expand Up @@ -32,6 +32,7 @@
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

/** Abstract base class for the source generating template for a single DTO. */
abstract class DtoImpl {
Expand Down Expand Up @@ -176,6 +177,19 @@ protected List<Method> getDtoGetters(Class<?> dto) {
return new ArrayList<>(getters.values());
}

/**
* Get the names of all the getters in the super DTO interface and upper ancestors.
*/
protected Set<String> getSuperGetterNames(Class<?> dto) {
final Map<String, Method> getters = new HashMap<>();
Class<?> superDto = getSuperDtoInterface(dto);
if (superDto != null) {
addDtoGetters(superDto, getters);
addSuperGetters(superDto, getters);
}
return getters.keySet();
}

/**
* Adds all getters from parent <b>NOT DTO</b> interfaces for given {@code dto} interface.
* Does not add method when it is already present in getters map.
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332 changes: 20 additions & 312 deletions ...i/che-core-api-dto/src/main/java/org/eclipse/che/dto/generator/DtoImplServerTemplate.java
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2 changes: 1 addition & 1 deletion platform-api/che-core-api-dto/src/main/java/org/eclipse/che/dto/generator/DtoTemplate.java
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Expand Up @@ -229,7 +229,7 @@ private void emitPreamble(StringBuilder builder) {
}
builder.append(" {\n\n");
if ("server".equals(implType)) {
builder.append(" private static final Gson gson = new GsonBuilder().disableHtmlEscaping().create();\n\n");
builder.append(" private static final Gson gson = org.eclipse.che.dto.server.DtoFactory.getInstance().getGson();\n\n");
builder.append(" @Override\n" +
" public void accept(org.eclipse.che.dto.server.DtoFactory dtoFactory) {\n");
for (DtoImpl dto : getDtoInterfaces()) {
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167 changes: 111 additions & 56 deletions platform-api/che-core-api-dto/src/main/java/org/eclipse/che/dto/server/DtoFactory.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,15 +21,23 @@
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonSyntaxException;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
Expand All @@ -42,7 +50,6 @@
* @author andrew00x
*/
public final class DtoFactory {
private static final Gson gson = new GsonBuilder().serializeNulls().create();

private static final Cache<Type, ParameterizedType> listTypeCache = new SynchronizedCache<>(
new LoadingValueSLRUCache<Type, ParameterizedType>(16, 16) {
Expand All @@ -65,6 +72,15 @@ public static DtoFactory getInstance() {
return INSTANCE;
}

/**
* Ge a {@link Gson} serializer that is configured to serializes/deserializes DTOs correctly.
*
* @return A Gson.
*/
public Gson getGson() {
return dtoGson;
}

/**
* Creates new instance of class which implements specified DTO interface.
*
Expand All @@ -81,6 +97,10 @@ public static <T> T newDto(Class<T> dtoInterface) {
// Additional mapping for implementation of DTO interfaces.
// It helps avoid reflection when need create copy of exited DTO instance.
private final Map<Class<?>, DtoProvider<?>> dtoImpl2Providers = new ConcurrentHashMap<>();
private final Gson dtoGson = new GsonBuilder()
.registerTypeAdapterFactory(new NullAsEmptyTAF<>(Collection.class, Collections.emptyList()))
.registerTypeAdapterFactory(new NullAsEmptyTAF<>(Map.class, Collections.emptyMap()))
.registerTypeAdapterFactory(new DtoInterfaceTAF()).create();

/**
* Created deep copy of DTO object.
Expand Down Expand Up @@ -165,7 +185,11 @@ public <T> T createDto(Class<T> dtoInterface) {
* if can't provide any implementation for specified interface
*/
public <T> T createDtoFromJson(String json, Class<T> dtoInterface) {
return getDtoProvider(dtoInterface).fromJson(json);
try {
return createDtoFromJson(new StringReader(json), dtoInterface);
} catch (IOException e) {
throw new RuntimeException(e); // won't happen
}
}

/**
Expand Down Expand Up @@ -197,14 +221,8 @@ public <T> T createDtoFromJson(JsonElement json, Class<T> dtoInterface) {
* if an i/o error occurs
*/
public <T> T createDtoFromJson(Reader json, Class<T> dtoInterface) throws IOException {
DtoProvider<T> dtoProvider = getDtoProvider(dtoInterface);
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(json);
String line;
while ((line = br.readLine()) != null) {
sb.append(line);
}
return dtoProvider.fromJson(sb.toString());
getDtoProvider(dtoInterface);
return dtoGson.fromJson(json, dtoInterface);
}

/**
Expand Down Expand Up @@ -238,16 +256,13 @@ public <T> T createDtoFromJson(InputStream json, Class<T> dtoInterface) throws I
* if can't provide any implementation for specified interface
*/
public <T> JsonArray<T> createListDtoFromJson(String json, Class<T> dtoInterface) {
final DtoProvider<T> dtoProvider = getDtoProvider(dtoInterface);
final List<JsonElement> list = gson.fromJson(json, listTypeCache.get(JsonElement.class));
final List<T> result = new ArrayList<>(list.size());
for (JsonElement e : list) {
result.add(dtoProvider.fromJson(e));
try {
return createListDtoFromJson(new StringReader(json), dtoInterface);
} catch (IOException e) {
throw new RuntimeException(e); // won't happen
}
return new JsonArrayImpl<>(result);
}


/**
* Parses the JSON data from the specified reader into list of objects of the specified type.
*
Expand All @@ -260,22 +275,9 @@ public <T> JsonArray<T> createListDtoFromJson(String json, Class<T> dtoInterface
* if can't provide any implementation for specified interface
*/
public <T> JsonArray<T> createListDtoFromJson(Reader json, Class<T> dtoInterface) throws IOException {
final DtoProvider<T> dtoProvider = getDtoProvider(dtoInterface);
final List<JsonElement> list;
try {
list = gson.fromJson(json, listTypeCache.get(JsonElement.class));
} catch (JsonSyntaxException e) {
final Throwable cause = e.getCause();
if (cause instanceof IOException) {
throw (IOException)cause;
}
throw e;
}
final List<T> result = new ArrayList<>(list.size());
for (JsonElement e : list) {
result.add(dtoProvider.fromJson(e));
}
return new JsonArrayImpl<>(result);
getDtoProvider(dtoInterface);
final List<T> list = parseDto(json, listTypeCache.get(dtoInterface));
return new JsonArrayImpl<>(list);
}

/**
Expand Down Expand Up @@ -309,13 +311,11 @@ public <T> JsonArray<T> createListDtoFromJson(InputStream json, Class<T> dtoInte
* if can't provide any implementation for specified interface
*/
public <T> JsonStringMap<T> createMapDtoFromJson(String json, Class<T> dtoInterface) {
final DtoProvider<T> dtoProvider = getDtoProvider(dtoInterface);
final Map<String, JsonElement> map = gson.fromJson(json, mapTypeCache.get(JsonElement.class));
final Map<String, T> result = new LinkedHashMap<>(map.size());
for (Map.Entry<String, JsonElement> e : map.entrySet()) {
result.put(e.getKey(), dtoProvider.fromJson(e.getValue()));
try {
return createMapDtoFromJson(new StringReader(json), dtoInterface);
} catch (IOException e) {
throw new RuntimeException(e); // won't happen
}
return new JsonStringMapImpl<>(result);
}


Expand All @@ -332,24 +332,10 @@ public <T> JsonStringMap<T> createMapDtoFromJson(String json, Class<T> dtoInterf
* @throws IOException
* if an i/o error occurs
*/
@SuppressWarnings("unchecked")
public <T> JsonStringMap<T> createMapDtoFromJson(Reader json, Class<T> dtoInterface) throws IOException {
final DtoProvider<T> dtoProvider = getDtoProvider(dtoInterface);
final Map<String, JsonElement> map;
try {
map = gson.fromJson(json, mapTypeCache.get(JsonElement.class));
} catch (JsonSyntaxException e) {
final Throwable cause = e.getCause();
if (cause instanceof IOException) {
throw (IOException)cause;
}
throw e;
}
final Map<String, T> result = new LinkedHashMap<>(map.size());
for (Map.Entry<String, JsonElement> e : map.entrySet()) {
result.put(e.getKey(), dtoProvider.fromJson(e.getValue()));
}
return new JsonStringMapImpl<>(result);
getDtoProvider(dtoInterface);
final Map<String, T> map = parseDto(json, mapTypeCache.get(dtoInterface));
return new JsonStringMapImpl<>(map);
}

/**
Expand Down Expand Up @@ -380,6 +366,22 @@ private <T> DtoProvider<T> getDtoProvider(Class<T> dtoInterface) {
return (DtoProvider<T>)dtoProvider;
}

/**
* Parse a JSON string that contains DTOs, propagating JSON exceptions correctly if they are caused by failures in
* the given Reader. Real JSON syntax exceptions are propagated as-is.
*/
private <T> T parseDto(Reader json, Type type) throws IOException {
try {
return dtoGson.fromJson(json, type);
} catch (JsonSyntaxException e) {
final Throwable cause = e.getCause();
if (cause instanceof IOException) {
throw (IOException) cause;
}
throw e;
}
}

/**
* Registers DtoProvider for DTO interface.
*
Expand Down Expand Up @@ -412,6 +414,59 @@ public boolean hasProvider(Class<?> dtoInterface) {
return dtoInterface2Providers.get(dtoInterface) != null;
}

/**
* A specialization of Gson's {@link ReflectiveTypeAdapterFactory} delegates operation on DTO interfaces to the
* corresponding implementation classes. The implementation classes generated correctly by the DTO Gson.
*
* @author tareq.sha@gmail.com
*/
private class DtoInterfaceTAF implements TypeAdapterFactory {
@Override
@SuppressWarnings("unchecked")
public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
DtoProvider<?> prov = dtoInterface2Providers.get(type.getRawType());
if (prov != null) {
return (TypeAdapter<T>) gson.getAdapter(prov.getImplClass());
}
return null;
}
}

/**
* Wraps Gson's default List/Map adapter factories serialize null List/Map fields as empty instead.
*
* @author tareq.sha@gmail.com
*/
private static class NullAsEmptyTAF<U> implements TypeAdapterFactory {
final Class<?> matchedClass;
final U defaultValue;

NullAsEmptyTAF(Class<U> matchedClass, U defaultValue) {
this.matchedClass = matchedClass;
this.defaultValue = defaultValue;
}

@Override
@SuppressWarnings("unchecked")
public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
if (!matchedClass.isAssignableFrom(type.getRawType())) {
return null;
}
TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
return new TypeAdapter<T>() {
@Override
public void write(JsonWriter out, T value) throws IOException {
delegate.write(out, value != null ? value : (T) defaultValue);
}

@Override
public T read(JsonReader in) throws IOException {
return delegate.read(in);
}
};
}
}

static {
for (DtoFactoryVisitor visitor : ServiceLoader.load(DtoFactoryVisitor.class)) {
visitor.accept(INSTANCE);
Expand Down
6 changes: 6 additions & 0 deletions platform-api/che-core-api-dto/src/main/java/org/eclipse/che/dto/server/JsonArrayImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;

import java.io.Writer;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
Expand Down Expand Up @@ -154,6 +155,11 @@ public String toJson() {
return gson.toJson(this);
}

@Override
public void toJson(Writer w) {
gson.toJson(this, w);
}

@Override
public JsonElement toJsonElement() {
return gson.toJsonTree(this);
Expand Down
4 changes: 4 additions & 0 deletions platform-api/che-core-api-dto/src/main/java/org/eclipse/che/dto/server/JsonSerializable.java
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
package org.eclipse.che.dto.server;

import java.io.Serializable;
import java.io.Writer;

import com.google.gson.JsonElement;

Expand All @@ -23,6 +24,9 @@ public interface JsonSerializable extends Serializable {
/** Serializes DTO to JSON format. */
String toJson();

/** Serialize the DTO to JSON text through the given Writer. */
void toJson(Writer w);

/** Serializes DTO to JSON object. */
JsonElement toJsonElement();
}
6 changes: 6 additions & 0 deletions ...form-api/che-core-api-dto/src/main/java/org/eclipse/che/dto/server/JsonStringMapImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;

import java.io.Writer;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
Expand Down Expand Up @@ -101,6 +102,11 @@ public String toJson() {
return gson.toJson(this);
}

@Override
public void toJson(Writer w) {
gson.toJson(this, w);
}

@Override
public JsonElement toJsonElement() {
return gson.toJsonTree(this);
Expand Down
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