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Fieldjava.lang.reflect

Java 1.1

This class represents a field of a class. Instances of Field are obtained by calling the getField( ) and related methods of java.lang.Class. Field implements the Member interface, so once you have obtained a Field object, you can use getName( ) , getModifiers( ), and getdeclaringClass( ) to determine the name, modifiers, and class of the field. Additionally, getType( ) returns the type of the field.

The set( ) method sets the value of the represented field for a specified object. (If the represented field is static, no object need be specified, of course.) If the field is of a primitive type, its value can be specified using a wrapper object of type Boolean, Integer, and so on, or it can be set using the setBoolean( ), setInt( ), and related methods. Similarly, the get( ) method queries the value of the represented field for a specified object and returns the field value as an Object. Various other methods query the field value and return it as various primitive types.

In Java 5.0, Field implements AnnotatedElement to support reflection on field annotations. The new getGenericType( ) method supports reflection on the generic type of fields, and isEnumConstant( ) supports fields of enum types.

Figure 10-93. java.lang.reflect.Field


public final class Field extends AccessibleObject implements Member {
// No Constructor
// Public Instance Methods
     public Object get(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public boolean getBoolean(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public byte getByte(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public char getChar(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public double getDouble(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public float getFloat(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
5.0  public Type getGenericType( );  
     public int getInt(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public long getLong(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public short getShort(Object obj) 
throws IllegalArgumentException, IllegalAccessException;  
     public Class<?> getType( );  
5.0  public boolean isEnumConstant( );  
     public void set(Object obj, Object value) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setBoolean(Object obj, boolean z) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setByte(Object obj, byte b) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setChar(Object obj, char c) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setDouble(Object obj, double d) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setFloat(Object obj, float f) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setInt(Object obj, int i) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setLong(Object obj, long l) 
throws IllegalArgumentException, IllegalAccessException;  
     public void setShort(Object obj, short s) 
throws IllegalArgumentException, IllegalAccessException;  
5.0  public String toGenericString( );  
// Methods Implementing Member
     public Class<?> getDeclaringClass( );  
     public int getModifiers( );  
     public String getName( );  
5.0  public boolean isSynthetic( );  
// Public Methods Overriding AccessibleObject
5.0  public <T extends java.lang.annotation.Annotation> T getAnnotation
(Class<T> annotationClass);  
5.0  public java.lang.annotation.Annotation[ ] getDeclaredAnnotations( );  
// Public Methods Overriding Object
     public boolean equals(Object obj);  
     public int hashCode( );  
     public String toString( );  
}

Returned By

Class.{getDeclaredField( ), getdeclaredFields( ), getField( ), getFields( )}

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