lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java - avro - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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 org.apache.avro.reflect;

 import java.io.IOException;
 import java.lang.reflect.Array;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Map;

 import org.apache.avro.AvroRuntimeException;
 import org.apache.avro.Conversion;
 import org.apache.avro.LogicalType;
 import org.apache.avro.Schema;
 import org.apache.avro.Schema.Field;
 import org.apache.avro.generic.IndexedRecord;
 import org.apache.avro.io.Decoder;
 import org.apache.avro.io.ResolvingDecoder;
 import org.apache.avro.specific.SpecificData;
 import org.apache.avro.specific.SpecificDatumReader;

 /**
  * {@link org.apache.avro.io.DatumReader DatumReader} for existing classes via
  * Java reflection.
  */
 public class ReflectDatumReader<T> extends SpecificDatumReader<T> {
   public ReflectDatumReader() {
     this(null, null, ReflectData.get());
   }

   /** Construct for reading instances of a class. */
   public ReflectDatumReader(Class<T> c) {
     this(new ReflectData(c.getClassLoader()));
     setSchema(getSpecificData().getSchema(c));
   }

   /** Construct where the writer's and reader's schemas are the same. */
   public ReflectDatumReader(Schema root) {
     this(root, root, ReflectData.get());
   }

   /** Construct given writer's and reader's schema. */
   public ReflectDatumReader(Schema writer, Schema reader) {
     this(writer, reader, ReflectData.get());
   }

   /** Construct given writer's and reader's schema and the data model. */
   public ReflectDatumReader(Schema writer, Schema reader, ReflectData data) {
     super(writer, reader, data);
   }

   /** Construct given a {@link ReflectData}. */
   public ReflectDatumReader(ReflectData data) {
     super(data);
   }

   @Override
   protected Object newArray(Object old, int size, Schema schema) {
     Class<?> collectionClass =
       ReflectData.getClassProp(schema, SpecificData.CLASS_PROP);
     Class<?> elementClass =
       ReflectData.getClassProp(schema, SpecificData.ELEMENT_PROP);

     if (elementClass == null) {
       // see if the element class will be converted and use that class
       // logical types cannot conflict with java-element-class
       Conversion<?> elementConversion = getData()
           .getConversionFor(schema.getElementType().getLogicalType());
       if (elementConversion != null) {
         elementClass = elementConversion.getConvertedType();
       }
     }

     if (collectionClass == null && elementClass == null)
       return super.newArray(old, size, schema);   // use specific/generic

     if (collectionClass != null && !collectionClass.isArray()) {
       if (old instanceof Collection) {
         ((Collection<?>)old).clear();
         return old;
       }
       if (collectionClass.isAssignableFrom(ArrayList.class))
         return new ArrayList<Object>();
       return SpecificData.newInstance(collectionClass, schema);
     }

     if (elementClass == null) {
       elementClass = collectionClass.getComponentType();
     }
     if (elementClass == null) {
       ReflectData data = (ReflectData)getData();
       elementClass = data.getClass(schema.getElementType());
     }
     return Array.newInstance(elementClass, size);
   }

   @Override
   protected Object peekArray(Object array) {
     return null;
   }

   @Override
   protected void addToArray(Object array, long pos, Object e) {
     throw new AvroRuntimeException("reflectDatumReader does not use addToArray");
   }

   @Override
   /** Called to read an array instance.  May be overridden for alternate array
    * representations.*/
   protected Object readArray(Object old, Schema expected, ResolvingDecoder in)
       throws IOException {
     Schema expectedType = expected.getElementType();
     long l = in.readArrayStart();
     if (l <= 0) {
       return newArray(old, 0, expected);
     }
     Object array = newArray(old, (int) l, expected);
     if (array instanceof Collection) {
       @SuppressWarnings("unchecked")
       Collection<Object> c = (Collection<Object>) array;
       return readCollection(c, expectedType, l, in);
     } else if (array instanceof Map) {
       // Only for non-string keys, we can use NS_MAP_* fields
       // So we check the samee explicitly here
       if (ReflectData.isNonStringMapSchema(expected)) {
         Collection<Object> c = new ArrayList<Object> ();
         readCollection(c, expectedType, l, in);
         Map m = (Map)array;
         for (Object ele: c) {
           IndexedRecord rec = ((IndexedRecord)ele);
           Object key = rec.get(ReflectData.NS_MAP_KEY_INDEX);
           Object value = rec.get(ReflectData.NS_MAP_VALUE_INDEX);
           m.put (key, value);
         }
         return array;
       } else {
         String msg = "Expected a schema of map with non-string keys but got " + expected;
         throw new AvroRuntimeException(msg);
       }
     } else {
       return readJavaArray(array, expectedType, l, in);
     }
   }

   private Object readJavaArray(Object array, Schema expectedType, long l,
       ResolvingDecoder in) throws IOException {
     Class<?> elementType = array.getClass().getComponentType();
     if (elementType.isPrimitive()) {
       return readPrimitiveArray(array, elementType, l, in);
     } else {
       return readObjectArray((Object[]) array, expectedType, l, in);
     }
   }

   private Object readPrimitiveArray(Object array, Class<?> c, long l, ResolvingDecoder in)
       throws IOException {
     return ArrayAccessor.readArray(array, c, l, in);
   }

   private Object readObjectArray(Object[] array, Schema expectedType, long l,
       ResolvingDecoder in) throws IOException {
     LogicalType logicalType = expectedType.getLogicalType();
     Conversion<?> conversion = getData().getConversionFor(logicalType);
     int index = 0;
     if (logicalType != null && conversion != null) {
       do {
         int limit = index + (int) l;
         while (index < limit) {
           Object element = readWithConversion(
               null, expectedType, logicalType, conversion, in);
           array[index] = element;
           index++;
         }
       } while ((l = in.arrayNext()) > 0);
     } else {
       do {
         int limit = index + (int) l;
         while (index < limit) {
           Object element = readWithoutConversion(null, expectedType, in);
           array[index] = element;
           index++;
         }
       } while ((l = in.arrayNext()) > 0);
     }
     return array;
   }

   private Object readCollection(Collection<Object> c, Schema expectedType,
       long l, ResolvingDecoder in) throws IOException {
     LogicalType logicalType = expectedType.getLogicalType();
     Conversion<?> conversion = getData().getConversionFor(logicalType);
     if (logicalType != null && conversion != null) {
       do {
         for (int i = 0; i < l; i++) {
           Object element = readWithConversion(
               null, expectedType, logicalType, conversion, in);
           c.add(element);
         }
       } while ((l = in.arrayNext()) > 0);
     } else {
       do {
         for (int i = 0; i < l; i++) {
           Object element = readWithoutConversion(null, expectedType, in);
           c.add(element);
         }
       } while ((l = in.arrayNext()) > 0);
     }
     return c;
   }

   @Override
   protected Object readString(Object old, Decoder in) throws IOException {
     return super.readString(null, in).toString();
   }

   @Override
   protected Object createString(String value) { return value; }

   @Override
   protected Object readBytes(Object old, Schema s, Decoder in)
     throws IOException {
     ByteBuffer bytes = in.readBytes(null);
     Class<?> c = ReflectData.getClassProp(s, SpecificData.CLASS_PROP);
     if (c != null && c.isArray()) {
       byte[] result = new byte[bytes.remaining()];
       bytes.get(result);
       return result;
     } else {
       return bytes;
     }
   }

   @Override
   protected Object readInt(Object old,
                            Schema expected, Decoder in) throws IOException {
     Object value = in.readInt();
     String intClass = expected.getProp(SpecificData.CLASS_PROP);
     if (Byte.class.getName().equals(intClass))
       value = ((Integer)value).byteValue();
     else if (Short.class.getName().equals(intClass))
       value = ((Integer)value).shortValue();
     else if (Character.class.getName().equals(intClass))
         value = ((Character)(char)(int)(Integer)value);
     return value;
   }

   @Override
   protected void readField(Object record, Field f, Object oldDatum,
       ResolvingDecoder in, Object state) throws IOException {
     if (state != null) {
       FieldAccessor accessor = ((FieldAccessor[]) state)[f.pos()];
       if (accessor != null) {
         if (accessor.supportsIO()
             && (!Schema.Type.UNION.equals(f.schema().getType())
                 || accessor.isCustomEncoded())) {
           accessor.read(record, in);
           return;
         }
         if (accessor.isStringable()) {
           try {
             String asString = (String) read(null, f.schema(), in);
             accessor.set(record, asString == null
               ? null
               : newInstanceFromString(accessor.getField().getType(), asString));
             return;
           } catch (Exception e) {
             throw new AvroRuntimeException("Failed to read Stringable", e);
           }
         }
         LogicalType logicalType = f.schema().getLogicalType();
         if (logicalType != null) {
           Conversion<?> conversion = getData().getConversionByClass(
               accessor.getField().getType(), logicalType);
           if (conversion != null) {
             try {
               accessor.set(record, convert(
                   readWithoutConversion(oldDatum, f.schema(), in),
                   f.schema(), logicalType, conversion));
             } catch (IllegalAccessException e) {
               throw new AvroRuntimeException("Failed to set " + f);
             }
             return;
           }
         }
         try {
           accessor.set(record,
               readWithoutConversion(oldDatum, f.schema(), in));
           return;
         } catch (IllegalAccessException e) {
           throw new AvroRuntimeException("Failed to set " + f);
         }
       }
     }
     super.readField(record, f, oldDatum, in, state);
   }
 }
	/**
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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 org.apache.avro.reflect;

	import java.io.IOException;
	import java.lang.reflect.Array;
	import java.nio.ByteBuffer;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Map;

	import org.apache.avro.AvroRuntimeException;
	import org.apache.avro.Conversion;
	import org.apache.avro.LogicalType;
	import org.apache.avro.Schema;
	import org.apache.avro.Schema.Field;
	import org.apache.avro.generic.IndexedRecord;
	import org.apache.avro.io.Decoder;
	import org.apache.avro.io.ResolvingDecoder;
	import org.apache.avro.specific.SpecificData;
	import org.apache.avro.specific.SpecificDatumReader;

	/**
	* {@link org.apache.avro.io.DatumReader DatumReader} for existing classes via
	* Java reflection.
	*/
	public class ReflectDatumReader<T> extends SpecificDatumReader<T> {
	public ReflectDatumReader() {
	this(null, null, ReflectData.get());
	}

	/** Construct for reading instances of a class. */
	public ReflectDatumReader(Class<T> c) {
	this(new ReflectData(c.getClassLoader()));
	setSchema(getSpecificData().getSchema(c));
	}

	/** Construct where the writer's and reader's schemas are the same. */
	public ReflectDatumReader(Schema root) {
	this(root, root, ReflectData.get());
	}

	/** Construct given writer's and reader's schema. */
	public ReflectDatumReader(Schema writer, Schema reader) {
	this(writer, reader, ReflectData.get());
	}

	/** Construct given writer's and reader's schema and the data model. */
	public ReflectDatumReader(Schema writer, Schema reader, ReflectData data) {
	super(writer, reader, data);
	}

	/** Construct given a {@link ReflectData}. */
	public ReflectDatumReader(ReflectData data) {
	super(data);
	}

	@Override
	protected Object newArray(Object old, int size, Schema schema) {
	Class<?> collectionClass =
	ReflectData.getClassProp(schema, SpecificData.CLASS_PROP);
	Class<?> elementClass =
	ReflectData.getClassProp(schema, SpecificData.ELEMENT_PROP);

	if (elementClass == null) {
	// see if the element class will be converted and use that class
	// logical types cannot conflict with java-element-class
	Conversion<?> elementConversion = getData()
	.getConversionFor(schema.getElementType().getLogicalType());
	if (elementConversion != null) {
	elementClass = elementConversion.getConvertedType();
	}
	}

	if (collectionClass == null && elementClass == null)
	return super.newArray(old, size, schema); // use specific/generic

	if (collectionClass != null && !collectionClass.isArray()) {
	if (old instanceof Collection) {
	((Collection<?>)old).clear();
	return old;
	}
	if (collectionClass.isAssignableFrom(ArrayList.class))
	return new ArrayList<Object>();
	return SpecificData.newInstance(collectionClass, schema);
	}

	if (elementClass == null) {
	elementClass = collectionClass.getComponentType();
	}
	if (elementClass == null) {
	ReflectData data = (ReflectData)getData();
	elementClass = data.getClass(schema.getElementType());
	}
	return Array.newInstance(elementClass, size);
	}

	@Override
	protected Object peekArray(Object array) {
	return null;
	}

	@Override
	protected void addToArray(Object array, long pos, Object e) {
	throw new AvroRuntimeException("reflectDatumReader does not use addToArray");
	}

	@Override
	/** Called to read an array instance. May be overridden for alternate array
	* representations.*/
	protected Object readArray(Object old, Schema expected, ResolvingDecoder in)
	throws IOException {
	Schema expectedType = expected.getElementType();
	long l = in.readArrayStart();
	if (l <= 0) {
	return newArray(old, 0, expected);
	}
	Object array = newArray(old, (int) l, expected);
	if (array instanceof Collection) {
	@SuppressWarnings("unchecked")
	Collection<Object> c = (Collection<Object>) array;
	return readCollection(c, expectedType, l, in);
	} else if (array instanceof Map) {
	// Only for non-string keys, we can use NS_MAP_* fields
	// So we check the samee explicitly here
	if (ReflectData.isNonStringMapSchema(expected)) {
	Collection<Object> c = new ArrayList<Object> ();
	readCollection(c, expectedType, l, in);
	Map m = (Map)array;
	for (Object ele: c) {
	IndexedRecord rec = ((IndexedRecord)ele);
	Object key = rec.get(ReflectData.NS_MAP_KEY_INDEX);
	Object value = rec.get(ReflectData.NS_MAP_VALUE_INDEX);
	m.put (key, value);
	}
	return array;
	} else {
	String msg = "Expected a schema of map with non-string keys but got " + expected;
	throw new AvroRuntimeException(msg);
	}
	} else {
	return readJavaArray(array, expectedType, l, in);
	}
	}

	private Object readJavaArray(Object array, Schema expectedType, long l,
	ResolvingDecoder in) throws IOException {
	Class<?> elementType = array.getClass().getComponentType();
	if (elementType.isPrimitive()) {
	return readPrimitiveArray(array, elementType, l, in);
	} else {
	return readObjectArray((Object[]) array, expectedType, l, in);
	}
	}

	private Object readPrimitiveArray(Object array, Class<?> c, long l, ResolvingDecoder in)
	throws IOException {
	return ArrayAccessor.readArray(array, c, l, in);
	}

	private Object readObjectArray(Object[] array, Schema expectedType, long l,
	ResolvingDecoder in) throws IOException {
	LogicalType logicalType = expectedType.getLogicalType();
	Conversion<?> conversion = getData().getConversionFor(logicalType);
	int index = 0;
	if (logicalType != null && conversion != null) {
	do {
	int limit = index + (int) l;
	while (index < limit) {
	Object element = readWithConversion(
	null, expectedType, logicalType, conversion, in);
	array[index] = element;
	index++;
	}
	} while ((l = in.arrayNext()) > 0);
	} else {
	do {
	int limit = index + (int) l;
	while (index < limit) {
	Object element = readWithoutConversion(null, expectedType, in);
	array[index] = element;
	index++;
	}
	} while ((l = in.arrayNext()) > 0);
	}
	return array;
	}

	private Object readCollection(Collection<Object> c, Schema expectedType,
	long l, ResolvingDecoder in) throws IOException {
	LogicalType logicalType = expectedType.getLogicalType();
	Conversion<?> conversion = getData().getConversionFor(logicalType);
	if (logicalType != null && conversion != null) {
	do {
	for (int i = 0; i < l; i++) {
	Object element = readWithConversion(
	null, expectedType, logicalType, conversion, in);
	c.add(element);
	}
	} while ((l = in.arrayNext()) > 0);
	} else {
	do {
	for (int i = 0; i < l; i++) {
	Object element = readWithoutConversion(null, expectedType, in);
	c.add(element);
	}
	} while ((l = in.arrayNext()) > 0);
	}
	return c;
	}

	@Override
	protected Object readString(Object old, Decoder in) throws IOException {
	return super.readString(null, in).toString();
	}

	@Override
	protected Object createString(String value) { return value; }

	@Override
	protected Object readBytes(Object old, Schema s, Decoder in)
	throws IOException {
	ByteBuffer bytes = in.readBytes(null);
	Class<?> c = ReflectData.getClassProp(s, SpecificData.CLASS_PROP);
	if (c != null && c.isArray()) {
	byte[] result = new byte[bytes.remaining()];
	bytes.get(result);
	return result;
	} else {
	return bytes;
	}
	}

	@Override
	protected Object readInt(Object old,
	Schema expected, Decoder in) throws IOException {
	Object value = in.readInt();
	String intClass = expected.getProp(SpecificData.CLASS_PROP);
	if (Byte.class.getName().equals(intClass))
	value = ((Integer)value).byteValue();
	else if (Short.class.getName().equals(intClass))
	value = ((Integer)value).shortValue();
	else if (Character.class.getName().equals(intClass))
	value = ((Character)(char)(int)(Integer)value);
	return value;
	}

	@Override
	protected void readField(Object record, Field f, Object oldDatum,
	ResolvingDecoder in, Object state) throws IOException {
	if (state != null) {
	FieldAccessor accessor = ((FieldAccessor[]) state)[f.pos()];
	if (accessor != null) {
	if (accessor.supportsIO()
	&& (!Schema.Type.UNION.equals(f.schema().getType())
	\|\| accessor.isCustomEncoded())) {
	accessor.read(record, in);
	return;
	}
	if (accessor.isStringable()) {
	try {
	String asString = (String) read(null, f.schema(), in);
	accessor.set(record, asString == null
	? null
	: newInstanceFromString(accessor.getField().getType(), asString));
	return;
	} catch (Exception e) {
	throw new AvroRuntimeException("Failed to read Stringable", e);
	}
	}
	LogicalType logicalType = f.schema().getLogicalType();
	if (logicalType != null) {
	Conversion<?> conversion = getData().getConversionByClass(
	accessor.getField().getType(), logicalType);
	if (conversion != null) {
	try {
	accessor.set(record, convert(
	readWithoutConversion(oldDatum, f.schema(), in),
	f.schema(), logicalType, conversion));
	} catch (IllegalAccessException e) {
	throw new AvroRuntimeException("Failed to set " + f);
	}
	return;
	}
	}
	try {
	accessor.set(record,
	readWithoutConversion(oldDatum, f.schema(), in));
	return;
	} catch (IllegalAccessException e) {
	throw new AvroRuntimeException("Failed to set " + f);
	}
	}
	}
	super.readField(record, f, oldDatum, in, state);
	}
	}