org.apache.juneau.internal.ObjectUtils Maven / Gradle / Ivy
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// * 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.juneau.internal;
import java.lang.reflect.*;
import java.util.*;
import org.apache.juneau.*;
import org.apache.juneau.transform.*;
/**
* Utility class for efficiently converting objects between types.
*
*
* If the value isn't an instance of the specified type, then converts the value if possible.
*
*
* The following conversions are valid:
*
* Convert to type Valid input value types Notes
*
* A class that is the normal type of a registered {@link PojoSwap}.
*
*
* A value whose class matches the transformed type of that registered {@link PojoSwap}.
*
*
*
*
*
* A class that is the transformed type of a registered {@link PojoSwap}.
*
*
* A value whose class matches the normal type of that registered {@link PojoSwap}.
*
*
*
*
*
* {@code Number} (e.g. {@code Integer}, {@code Short}, {@code Float},...)
*
Number.TYPE (e.g. Integer.TYPE ,
* Short.TYPE , Float.TYPE ,...)
*
*
* {@code Number}, {@code String}, null
*
*
* For primitive {@code TYPES}, null returns the JVM default value for that type.
*
*
*
*
* {@code Map} (e.g. {@code Map}, {@code HashMap}, {@code TreeMap}, {@code ObjectMap})
*
*
* {@code Map}
*
*
* If {@code Map} is not constructible, a {@code ObjectMap} is created.
*
*
*
*
* {@code Collection} (e.g. {@code List}, {@code LinkedList}, {@code HashSet}, {@code ObjectList})
*
*
* {@code Collection
*
* If {@code Collection} is not constructible, a {@code ObjectList} is created.
*
*
*
*
* {@code X[]} (array of any type X)
*
*
* {@code List}
*
*
*
*
*
* {@code X[][]} (multi-dimensional arrays)
*
*
* {@code List>}
*
{@code List}
*
{@code List[]}
*
*
*
*
*
* {@code Enum}
*
*
* {@code String}
*
*
*
*
*
* Bean
*
*
* {@code Map}
*
*
*
*
*
* {@code String}
*
*
* Anything
*
*
* Arrays are converted to JSON arrays
*
*
*
*
* Anything with one of the following methods:
*
public static T fromString(String)
public static T valueOf(String)
public T(String)
*
* String
*
*
*
*
*
*
*/
public class ObjectUtils {
// Session objects are usually not thread safe, but we're not using any feature
// of bean sessions that would cause thread safety issues.
private static final BeanSession session = BeanContext.DEFAULT.createSession();
/**
* Converts the specified object to the specified type.
*
* @param The class type to convert the value to.
* @param value The value to convert.
* @param type The class type to convert the value to.
* @throws InvalidDataConversionException If the specified value cannot be converted to the specified type.
* @return The converted value.
*/
public static T convertToType(Object value, Class type) {
return session.convertToType(value, type);
}
/**
* Converts the specified object to the specified type.
*
* @param The class type to convert the value to.
* @param outer
* If class is a member class, this is the instance of the containing class.
* Should be null if not a member class.
* @param value The value to convert.
* @param type The class type to convert the value to.
* @throws InvalidDataConversionException If the specified value cannot be converted to the specified type.
* @return The converted value.
*/
public static T convertToMemberType(Object outer, Object value, Class type) {
return session.convertToMemberType(outer, value, type);
}
/**
* Returns true if the specified objects are equal.
*
*
* Gracefully handles null s.
*
* @param o1 Object #1
* @param o2 Object #2
* @return true if the objects are equal or both null .
*/
public static boolean equals(Object o1, Object o2) {
if (o1 == null && o2 == null)
return true;
if (o1 == null || o2 == null)
return false;
return o1.equals(o2);
}
/**
* Returns true if the specified object is empty.
*
*
* Return true if the value is any of the following:
*
* null
* - An empty Collection
*
- An empty Map
*
- An empty array
*
- An empty CharSequence
*
- An empty String when serialized to a string using {@link Object#toString()}.
*
*
* @param o The object to test.
* @return true if the specified object is empty.
*/
@SuppressWarnings("rawtypes")
public static boolean isEmpty(Object o) {
if (o == null)
return true;
if (o instanceof Collection)
return ((Collection)o).isEmpty();
if (o instanceof Map)
return ((Map)o).isEmpty();
if (o.getClass().isArray())
return (Array.getLength(o) == 0);
return o.toString().isEmpty();
}
}