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gwt-jackson is a GWT JSON serializer/deserializer mechanism based on Jackson annotations
/*
* Copyright 2013 Nicolas Morel
*
* 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.github.nmorel.gwtjackson.client;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.fasterxml.jackson.annotation.ObjectIdGenerator.IdKey;
import com.github.nmorel.gwtjackson.client.exception.JsonDeserializationException;
import com.github.nmorel.gwtjackson.client.stream.JsonReader;
import com.github.nmorel.gwtjackson.client.stream.impl.NonBufferedJsonReader;
import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsonUtils;
/**
* Context for the deserialization process.
*
* @author Nicolas Morel
*/
public class JsonDeserializationContext extends JsonMappingContext {
/**
* Builder for {@link JsonDeserializationContext}. To override default settings globally, you can extend this class, modify the
* default settings inside the constructor and tell the compiler to use your builder instead in your gwt.xml file :
*
* {@code
*
*
*
*
* }
*
*/
public static class Builder {
protected boolean failOnUnknownProperties = true;
protected boolean unwrapRootValue = false;
protected boolean acceptSingleValueAsArray = false;
protected boolean wrapExceptions = true;
protected boolean useSafeEval = true;
protected boolean readUnknownEnumValuesAsNull = false;
protected boolean useBrowserTimezone = false;
/**
* @deprecated Use {@link JsonDeserializationContext#builder()} instead. This constructor will be made protected in v1.0.
*/
@Deprecated
public Builder() { }
/**
* Determines whether encountering of unknown
* properties (ones that do not map to a property, and there is
* no "any setter" or handler that can handle it)
* should result in a failure (by throwing a
* {@link JsonDeserializationException}) or not.
* This setting only takes effect after all other handling
* methods for unknown properties have been tried, and
* property remains unhandled.
*
* Feature is enabled by default (meaning that a
* {@link JsonDeserializationException} will be thrown if an unknown property
* is encountered).
*
*/
public Builder failOnUnknownProperties( boolean failOnUnknownProperties ) {
this.failOnUnknownProperties = failOnUnknownProperties;
return this;
}
/**
* Feature to allow "unwrapping" root-level JSON value, to match setting of
* {@link JsonSerializationContext.Builder#wrapRootValue(boolean)} used for serialization.
* Will verify that the root JSON value is a JSON Object, and that it has
* a single property with expected root name. If not, a
* {@link JsonDeserializationException} is thrown; otherwise value of the wrapped property
* will be deserialized as if it was the root value.
*
* Feature is disabled by default.
*
*/
public Builder unwrapRootValue( boolean unwrapRootValue ) {
this.unwrapRootValue = unwrapRootValue;
return this;
}
/**
* Feature that determines whether it is acceptable to coerce non-array
* (in JSON) values to work with Java collection (arrays, java.util.Collection)
* types. If enabled, collection deserializers will try to handle non-array
* values as if they had "implicit" surrounding JSON array.
* This feature is meant to be used for compatibility/interoperability reasons,
* to work with packages (such as XML-to-JSON converters) that leave out JSON
* array in cases where there is just a single element in array.
*
* Feature is disabled by default.
*
*/
public Builder acceptSingleValueAsArray( boolean acceptSingleValueAsArray ) {
this.acceptSingleValueAsArray = acceptSingleValueAsArray;
return this;
}
/**
* Feature that determines whether gwt-jackson code should catch
* and wrap {@link RuntimeException}s (but never {@link Error}s!)
* to add additional information about
* location (within input) of problem or not. If enabled,
* exceptions will be caught and re-thrown; this can be
* convenient both in that all exceptions will be checked and
* declared, and so there is more contextual information.
* However, sometimes calling application may just want "raw"
* unchecked exceptions passed as is.
*
*
* Feature is enabled by default.
*/
public Builder wrapExceptions( boolean wrapExceptions ) {
this.wrapExceptions = wrapExceptions;
return this;
}
/**
* Feature that determines whether gwt-jackson should use {@link JsonUtils#safeEval(String)} or {@link JsonUtils#unsafeEval(String)}
* to deserialize {@link JavaScriptObject}
*
*
* {@link JsonUtils#safeEval(String)} is used by default.
*/
public Builder useSafeEval( boolean useSafeEval ) {
this.useSafeEval = useSafeEval;
return this;
}
/**
* Feature that determines whether gwt-jackson should return null for unknown enum values.
* Default is false which will throw {@link IllegalArgumentException} when unknown enum value is found.
*/
public Builder readUnknownEnumValuesAsNull( boolean readUnknownEnumValuesAsNull ) {
this.readUnknownEnumValuesAsNull = readUnknownEnumValuesAsNull;
return this;
}
/**
* Feature that specifies whether dates that doesn't contain timezone information
* are interpreted using the browser timezone or being relative to UTC (the default).
*/
public Builder useBrowserTimezone(boolean useBrowserTimezone) {
this.useBrowserTimezone = useBrowserTimezone;
return this;
}
public final JsonDeserializationContext build() {
return new JsonDeserializationContext( failOnUnknownProperties, unwrapRootValue, acceptSingleValueAsArray, wrapExceptions,
useSafeEval, readUnknownEnumValuesAsNull, useBrowserTimezone );
}
}
public static class DefaultBuilder extends Builder {
private DefaultBuilder() {}
}
public static Builder builder() {
return GWT.create( Builder.class );
}
private static final Logger logger = Logger.getLogger( "JsonDeserialization" );
private Map idToObject;
/*
* Deserialization options
*/
private final boolean failOnUnknownProperties;
private final boolean unwrapRootValue;
private final boolean acceptSingleValueAsArray;
private final boolean wrapExceptions;
private final boolean useSafeEval;
private final boolean readUnknownEnumValuesAsNull;
private final boolean useBrowserTimezone;
private JsonDeserializationContext( boolean failOnUnknownProperties, boolean unwrapRootValue, boolean acceptSingleValueAsArray,
boolean wrapExceptions, boolean useSafeEval, boolean readUnknownEnumValuesAsNull,
boolean useBrowserTimezone ) {
this.failOnUnknownProperties = failOnUnknownProperties;
this.unwrapRootValue = unwrapRootValue;
this.acceptSingleValueAsArray = acceptSingleValueAsArray;
this.wrapExceptions = wrapExceptions;
this.useSafeEval = useSafeEval;
this.readUnknownEnumValuesAsNull = readUnknownEnumValuesAsNull;
this.useBrowserTimezone = useBrowserTimezone;
}
@Override
public Logger getLogger() {
return logger;
}
/**
* @see Builder#failOnUnknownProperties(boolean)
*/
public boolean isFailOnUnknownProperties() {
return failOnUnknownProperties;
}
/**
* @see Builder#unwrapRootValue(boolean)
*/
public boolean isUnwrapRootValue() {
return unwrapRootValue;
}
/**
* @see Builder#acceptSingleValueAsArray(boolean)
*/
public boolean isAcceptSingleValueAsArray() {
return acceptSingleValueAsArray;
}
/**
* @see Builder#useSafeEval(boolean)
*/
public boolean isUseSafeEval() {
return useSafeEval;
}
/**
* @see Builder#readUnknownEnumValuesAsNull(boolean)
*/
public boolean isReadUnknownEnumValuesAsNull() {
return readUnknownEnumValuesAsNull;
}
/**
* @see Builder#adjustDatesToContextTimeZone(boolean)
*/
public boolean isUseBrowserTimezone() {
return useBrowserTimezone;
}
public JsonReader newJsonReader( String input ) {
JsonReader reader = new NonBufferedJsonReader( input );
reader.setLenient( true );
return reader;
}
/**
* Trace an error with current reader state and returns a corresponding exception.
*
* @param message error message
*
* @return a {@link JsonDeserializationException} with the given message
*/
public JsonDeserializationException traceError( String message ) {
return traceError( message, null );
}
/**
* Trace an error with current reader state and returns a corresponding exception.
*
* @param message error message
* @param reader current reader
*
* @return a {@link JsonDeserializationException} with the given message
*/
public JsonDeserializationException traceError( String message, JsonReader reader ) {
getLogger().log( Level.SEVERE, message );
traceReaderInfo( reader );
return new JsonDeserializationException( message );
}
/**
* Trace an error and returns a corresponding exception.
*
* @param cause cause of the error
*
* @return a {@link JsonDeserializationException} if we wrap the exceptions, the cause otherwise
*/
public RuntimeException traceError( RuntimeException cause ) {
getLogger().log( Level.SEVERE, "Error during deserialization", cause );
if ( wrapExceptions ) {
return new JsonDeserializationException( cause );
} else {
return cause;
}
}
/**
* Trace an error with current reader state and returns a corresponding exception.
*
* @param cause cause of the error
* @param reader current reader
*
* @return a {@link JsonDeserializationException} if we wrap the exceptions, the cause otherwise
*/
public RuntimeException traceError( RuntimeException cause, JsonReader reader ) {
RuntimeException exception = traceError( cause );
traceReaderInfo( reader );
return exception;
}
/**
* Trace the current reader state
*/
private void traceReaderInfo( JsonReader reader ) {
if ( null != reader && getLogger().isLoggable( Level.INFO ) ) {
getLogger().log( Level.INFO, "Error at line " + reader.getLineNumber() + " and column " + reader
.getColumnNumber() + " of input <" + reader.getInput() + ">" );
}
}
public void addObjectId( IdKey id, Object instance ) {
if ( null == idToObject ) {
idToObject = new HashMap();
}
idToObject.put( id, instance );
}
public Object getObjectWithId( IdKey id ) {
if ( null != idToObject ) {
return idToObject.get( id );
}
return null;
}
}
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