/*
* Copyright (c) 2008 Nathan Sweet
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
* is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
* IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.esotericsoftware.yamlbeans;
import static com.esotericsoftware.yamlbeans.parser.EventType.*;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import com.esotericsoftware.yamlbeans.Beans.Property;
import com.esotericsoftware.yamlbeans.parser.AliasEvent;
import com.esotericsoftware.yamlbeans.parser.CollectionStartEvent;
import com.esotericsoftware.yamlbeans.parser.Event;
import com.esotericsoftware.yamlbeans.parser.Parser;
import com.esotericsoftware.yamlbeans.parser.ScalarEvent;
import com.esotericsoftware.yamlbeans.parser.Parser.ParserException;
import com.esotericsoftware.yamlbeans.scalar.ScalarSerializer;
import com.esotericsoftware.yamlbeans.tokenizer.Tokenizer.TokenizerException;
/**
* Deserializes Java objects from YAML.
* @author <a href="mailto:misc@n4te.com">Nathan Sweet</a>
*/
public class YamlReader {
private final YamlConfig config;
Parser parser;
private final Map<String, Object> anchors = new HashMap();
public YamlReader (Reader reader) {
this(reader, new YamlConfig());
}
public YamlReader (Reader reader, YamlConfig config) {
this.config = config;
parser = new Parser(reader, config.readConfig.defaultVersion);
}
public YamlReader (String yaml) {
this(new StringReader(yaml));
}
public YamlReader (String yaml, YamlConfig config) {
this(new StringReader(yaml), config);
}
public YamlConfig getConfig () {
return config;
}
public void close () throws IOException {
parser.close();
anchors.clear();
}
/**
* Reads the next YAML document and deserializes it into an object. The type of object is defined by the YAML tag. If there is
* no YAML tag, the object will be an {@link ArrayList}, {@link HashMap}, or String.
*/
public Object read () throws YamlException {
return read(null);
}
/**
* Reads an object of the specified type from YAML.
* @param type The type of object to read. If null, behaves the same as {{@link #read()}.
*/
public <T> T read (Class<T> type) throws YamlException {
return read(type, null);
}
/**
* Reads an array, Map, List, or Collection object of the specified type from YAML, using the specified element type.
* @param type The type of object to read. If null, behaves the same as {{@link #read()}.
*/
public <T> T read (Class<T> type, Class elementType) throws YamlException {
try {
while (true) {
Event event = parser.getNextEvent();
if (event == null) return null;
if (event.type == STREAM_END) return null;
if (event.type == DOCUMENT_START) break;
}
return (T)readValue(type, elementType, null);
} catch (ParserException ex) {
throw new YamlException("Error parsing YAML.", ex);
} catch (TokenizerException ex) {
throw new YamlException("Error tokenizing YAML.", ex);
}
}
/**
* Reads an object from the YAML. Can be overidden to take some action for any of the objects returned.
*/
protected Object readValue (Class type, Class elementType, Class defaultType) throws YamlException, ParserException,
TokenizerException {
String tag = null, anchor = null;
Event event = parser.peekNextEvent();
switch (event.type) {
case ALIAS:
parser.getNextEvent();
anchor = ((AliasEvent)event).anchor;
Object value = anchors.get(anchor);
if (value == null) throw new YamlReaderException("Unknown anchor: " + anchor);
return value;
case MAPPING_START:
case SEQUENCE_START:
tag = ((CollectionStartEvent)event).tag;
anchor = ((CollectionStartEvent)event).anchor;
break;
case SCALAR:
tag = ((ScalarEvent)event).tag;
anchor = ((ScalarEvent)event).anchor;
break;
}
if (tag != null) {
type = config.tagToClass.get(tag);
if (type == null) {
try {
if (config.readConfig.classLoader != null)
type = Class.forName(tag, true, config.readConfig.classLoader);
else
type = Class.forName(tag);
} catch (ClassNotFoundException ex) {
throw new YamlReaderException("Unable to find class specified by tag: " + tag);
}
}
} else if (defaultType != null) {
type = defaultType;
}
return readValueInternal(type, elementType, anchor);
}
private Object readValueInternal (Class type, Class elementType, String anchor) throws YamlException, ParserException,
TokenizerException {
if (type == null || type == Object.class) {
Event event = parser.peekNextEvent();
switch (event.type) {
case MAPPING_START:
type = HashMap.class;
break;
case SCALAR:
type = String.class;
break;
case SEQUENCE_START:
type = ArrayList.class;
break;
default:
throw new YamlReaderException("Expected scalar, sequence, or mapping but found: " + event.type);
}
}
if (type == String.class) {
Event event = parser.getNextEvent();
if (event.type != SCALAR) throw new YamlReaderException("Expected scalar for String type but found: " + event.type);
String value = ((ScalarEvent)event).value;
if (anchor != null) anchors.put(anchor, value);
return value;
}
if (Beans.isScalar(type)) {
Event event = parser.getNextEvent();
if (event.type != SCALAR)
throw new YamlReaderException("Expected scalar for primitive type '" + type.getClass() + "' but found: " + event.type);
String value = ((ScalarEvent)event).value;
try {
Object convertedValue;
if (type == String.class) {
convertedValue = value;
} else if (type == Integer.TYPE) {
convertedValue = Integer.valueOf(value);
} else if (type == Integer.class) {
convertedValue = value.length() == 0 ? null : Integer.valueOf(value);
} else if (type == Boolean.TYPE) {
convertedValue = Boolean.valueOf(value);
} else if (type == Boolean.class) {
convertedValue = value.length() == 0 ? null : Boolean.valueOf(value);
} else if (type == Float.TYPE) {
convertedValue = Float.valueOf(value);
} else if (type == Float.class) {
convertedValue = value.length() == 0 ? null : Float.valueOf(value);
} else if (type == Double.TYPE) {
convertedValue = Double.valueOf(value);
} else if (type == Double.class) {
convertedValue = value.length() == 0 ? null : Double.valueOf(value);
} else if (type == Long.TYPE) {
convertedValue = Long.valueOf(value);
} else if (type == Long.class) {
convertedValue = value.length() == 0 ? null : Long.valueOf(value);
} else if (type == Short.TYPE) {
convertedValue = Short.valueOf(value);
} else if (type == Short.class) {
convertedValue = value.length() == 0 ? null : Short.valueOf(value);
} else if (type == Character.TYPE) {
convertedValue = value.charAt(0);
} else if (type == Character.class) {
convertedValue = value.length() == 0 ? null : value.charAt(0);
} else if (type == Byte.TYPE) {
convertedValue = Byte.valueOf(value);
} else if (type == Byte.class) {
convertedValue = value.length() == 0 ? null : Byte.valueOf(value);
} else
throw new YamlException("Unknown field type.");
if (anchor != null) anchors.put(anchor, convertedValue);
return convertedValue;
} catch (Exception ex) {
throw new YamlReaderException("Unable to convert value to required type \"" + type + "\": " + value, ex);
}
}
if (Enum.class.isAssignableFrom(type)) {
Event event = parser.getNextEvent();
if (event.type != SCALAR) throw new YamlReaderException("Expected scalar for enum type but found: " + event.type);
String enumValueName = ((ScalarEvent)event).value;
if (enumValueName.length() == 0) return null;
try {
return Enum.valueOf(type, enumValueName);
} catch (Exception ex) {
throw new YamlReaderException("Unable to find enum value '" + enumValueName + "' for enum class: " + type.getName());
}
}
for (Entry<Class, ScalarSerializer> entry : config.scalarSerializers.entrySet()) {
if (entry.getKey().isAssignableFrom(type)) {
ScalarSerializer serializer = entry.getValue();
Event event = parser.getNextEvent();
if (event.type != SCALAR)
throw new YamlReaderException("Expected scalar for type '" + type + "' to be deserialized by scalar serializer '"
+ serializer.getClass().getName() + "' but found: " + event.type);
Object value = serializer.read(((ScalarEvent)event).value);
if (anchor != null) anchors.put(anchor, value);
return value;
}
}
Event event = parser.peekNextEvent();
switch (event.type) {
case MAPPING_START: {
// Must be a map or an object.
event = parser.getNextEvent();
Object object;
try {
object = createObject(type);
} catch (InvocationTargetException ex) {
throw new YamlReaderException("Error creating object.", ex);
}
if (anchor != null) anchors.put(anchor, object);
while (true) {
if (parser.peekNextEvent().type == MAPPING_END) {
parser.getNextEvent();
break;
}
Object key = readValue(null, null, null);
// Explicit key/value pairs (using "? key\n: value\n") will come back as a map.
boolean isExplicitKey = key instanceof Map;
Object value = null;
if (isExplicitKey) {
Entry nameValuePair = (Entry)((Map)key).entrySet().iterator().next();
key = nameValuePair.getKey();
value = nameValuePair.getValue();
}
if (object instanceof Map) {
// Add to map.
if (!isExplicitKey) value = readValue(elementType, null, null);
((Map)object).put(key, value);
} else {
// Set field on object.
try {
Property property = Beans.getProperty(type, (String)key, config.beanProperties, config.privateFields, config);
if (property == null)
throw new YamlReaderException("Unable to find property '" + key + "' on class: " + type.getName());
Class propertyElementType = config.propertyToElementType.get(property);
Class propertyDefaultType = config.propertyToDefaultType.get(property);
if (!isExplicitKey) value = readValue(property.getType(), propertyElementType, propertyDefaultType);
property.set(object, value);
} catch (Exception ex) {
if (ex instanceof YamlReaderException) throw (YamlReaderException)ex;
throw new YamlReaderException("Error setting property '" + key + "' on class: " + type.getName(), ex);
}
}
}
if (object instanceof DeferredConstruction) {
try {
object = ((DeferredConstruction)object).construct();
if (anchor != null) anchors.put(anchor, object); // Update anchor with real object.
} catch (InvocationTargetException ex) {
throw new YamlReaderException("Error creating object.", ex);
}
}
return object;
}
case SEQUENCE_START: {
// Must be a collection or an array.
event = parser.getNextEvent();
Collection collection;
if (Collection.class.isAssignableFrom(type)) {
try {
collection = (Collection)Beans.createObject(type, config.privateConstructors);
} catch (InvocationTargetException ex) {
throw new YamlReaderException("Error creating object.", ex);
}
} else if (type.isArray()) {
collection = new ArrayList();
elementType = type.getComponentType();
} else
throw new YamlReaderException("A sequence is not a valid value for the type: " + type.getName());
if (!type.isArray() && anchor != null) anchors.put(anchor, collection);
while (true) {
event = parser.peekNextEvent();
if (event.type == SEQUENCE_END) {
parser.getNextEvent();
break;
}
collection.add(readValue(elementType, null, null));
}
if (!type.isArray()) return collection;
Object array = Array.newInstance(elementType, collection.size());
int i = 0;
for (Object object : collection)
Array.set(array, i++, object);
if (anchor != null) anchors.put(anchor, array);
return array;
}
case SCALAR:
// Interpret an empty scalar as null.
if (((ScalarEvent)event).value.length() == 0) {
event = parser.getNextEvent();
return null;
}
// Fall through.
default:
throw new YamlReaderException("Expected data for a " + type.getName() + " field but found: " + event.type);
}
}
/**
* Returns a new object of the requested type.
*/
protected Object createObject (Class type) throws InvocationTargetException {
// Use deferred construction if a non-zero-arg constructor is available.
DeferredConstruction deferredConstruction = Beans.getDeferredConstruction(type, config);
if (deferredConstruction != null) return deferredConstruction;
return Beans.createObject(type, config.privateConstructors);
}
public class YamlReaderException extends YamlException {
public YamlReaderException (String message, Throwable cause) {
super("Line " + parser.getLineNumber() + ", column " + parser.getColumn() + ": " + message, cause);
}
public YamlReaderException (String message) {
this(message, null);
}
}
public static void main (String[] args) throws Exception {
YamlReader reader = new YamlReader(new FileReader("test/test.yml"));
System.out.println(reader.read());
}
}