com.esotericsoftware.yamlbeans.YamlReader Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of yamlbeans Show documentation
Show all versions of yamlbeans Show documentation
Java object graphs, to and from YAML
/*
* 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.LinkedHashMap;
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.Parser.ParserException;
import com.esotericsoftware.yamlbeans.parser.ScalarEvent;
import com.esotericsoftware.yamlbeans.scalar.ScalarSerializer;
import com.esotericsoftware.yamlbeans.tokenizer.Tokenizer.TokenizerException;
/** Deserializes Java objects from YAML.
* @author Nathan Sweet */
public class YamlReader {
private final YamlConfig config;
Parser parser;
private final Map 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;
}
/** Return the object with the given alias, or null. This is only valid after objects have been read and before
* {@link #close()} */
public Object get (String alias) {
return anchors.get(alias);
}
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 read (Class 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 read (Class 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;
default:
}
return readValueInternal(this.chooseType(tag, defaultType, type), elementType, anchor);
}
private Class> chooseType (String tag, Class> defaultType, Class> providedType) throws YamlReaderException {
if (tag != null && config.readConfig.classTags) {
Class> userConfiguredByTag = config.tagToClass.get(tag);
if (userConfiguredByTag != null) {
return userConfiguredByTag;
}
ClassLoader classLoader = (config.readConfig.classLoader == null ? this.getClass().getClassLoader()
: config.readConfig.classLoader);
try {
Class> loadedFromTag = findTagClass(tag, classLoader);
if (loadedFromTag != null) {
return loadedFromTag;
}
} catch (ClassNotFoundException e) {
throw new YamlReaderException("Unable to find class specified by tag: " + tag);
}
}
if (defaultType != null) {
return defaultType;
}
// This may be null.
return providedType;
}
/** Used during reading when a tag is present, and {@link YamlConfig#setClassTag(String, Class)} was not used for that tag.
* Attempts to load the class corresponding to that tag.
*
* If this returns a non-null Class, that will be used as the deserialization type regardless of whether a type was explicitly
* asked for or if a default type exists.
*
* If this returns null, no guidance will be provided by the tag and we will fall back to the default type or a requested
* target type, if any exist.
*
* If this throws a ClassNotFoundException, parsing will fail.
*
* The default implementation is simply
*
*
* {@code Class.forName(tag, true, classLoader);}
*
*
* and never returns null.
*
* You can override this to handle cases where you do not want to respect the type tags found in a document - e.g., if they
* were output by another program using classes that do not exist on your classpath. */
protected Class> findTagClass (String tag, ClassLoader classLoader) throws ClassNotFoundException {
return Class.forName(tag, true, classLoader);
}
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 = LinkedHashMap.class;
break;
case SCALAR:
if (config.readConfig.guessNumberTypes) {
String value = ((ScalarEvent)event).value;
if (value != null) {
try {
Integer convertedValue = Integer.decode(value);
if (anchor != null) anchors.put(anchor, convertedValue);
parser.getNextEvent();
return convertedValue;
} catch (NumberFormatException ex) {
}
try {
Float convertedValue = Float.valueOf(value);
if (anchor != null) anchors.put(anchor, convertedValue);
parser.getNextEvent();
return convertedValue;
} catch (NumberFormatException ex) {
}
}
}
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 = value.length() == 0 ? 0 : Integer.decode(value);
} else if (type == Integer.class) {
convertedValue = value.length() == 0 ? null : Integer.decode(value);
} else if (type == Boolean.TYPE) {
convertedValue = value.length() == 0 ? false : Boolean.valueOf(value);
} else if (type == Boolean.class) {
convertedValue = value.length() == 0 ? null : Boolean.valueOf(value);
} else if (type == Float.TYPE) {
convertedValue = value.length() == 0 ? 0 : Float.valueOf(value);
} else if (type == Float.class) {
convertedValue = value.length() == 0 ? null : Float.valueOf(value);
} else if (type == Double.TYPE) {
convertedValue = value.length() == 0 ? 0 : Double.valueOf(value);
} else if (type == Double.class) {
convertedValue = value.length() == 0 ? null : Double.valueOf(value);
} else if (type == Long.TYPE) {
convertedValue = value.length() == 0 ? 0 : Long.decode(value);
} else if (type == Long.class) {
convertedValue = value.length() == 0 ? null : Long.decode(value);
} else if (type == Short.TYPE) {
convertedValue = value.length() == 0 ? 0 : Short.decode(value);
} else if (type == Short.class) {
convertedValue = value.length() == 0 ? null : Short.decode(value);
} else if (type == Character.TYPE) {
convertedValue = value.length() == 0 ? 0 : value.charAt(0);
} else if (type == Character.class) {
convertedValue = value.length() == 0 ? null : value.charAt(0);
} else if (type == Byte.TYPE) {
convertedValue = value.length() == 0 ? 0 : Byte.decode(value);
} else if (type == Byte.class) {
convertedValue = value.length() == 0 ? null : Byte.decode(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 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);
ArrayList keys = new ArrayList();
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 (config.tagSuffix != null) {
Event nextEvent = parser.peekNextEvent();
switch (nextEvent.type) {
case MAPPING_START:
case SEQUENCE_START:
((Map)object).put(key + config.tagSuffix, ((CollectionStartEvent)nextEvent).tag);
break;
case SCALAR:
((Map)object).put(key + config.tagSuffix, ((ScalarEvent)nextEvent).tag);
break;
}
}
if (!isExplicitKey) value = readValue(elementType, null, null);
if (!config.allowDuplicates && ((Map)object).containsKey(key)) {
throw new YamlReaderException("Duplicate key found '" + key + "'");
}
if (config.readConfig.autoMerge && "<<".equals(key) && value != null)
mergeMap((Map)object, value);
else
((Map)object).put(key, value);
} else {
// Set field on object.
try {
if (!config.allowDuplicates && keys.contains(key)) {
throw new YamlReaderException("Duplicate key found '" + key + "'");
}
keys.add(key);
Property property = Beans.getProperty(type, (String)key, config.beanProperties, config.privateFields, config);
if (property == null) {
if (config.readConfig.ignoreUnknownProperties) continue;
throw new YamlReaderException("Unable to find property '" + key + "' on class: " + type.getName());
}
Class propertyElementType = config.propertyToElementType.get(property);
if (propertyElementType == null) propertyElementType = property.getElementType();
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);
}
}
/** see http://yaml.org/type/merge.html */
@SuppressWarnings("unchecked")
private void mergeMap (Map dest, Object source) throws YamlReaderException {
if (source instanceof Collection) {
for (Object item : ((Collection
© 2015 - 2024 Weber Informatics LLC | Privacy Policy