```
public interface ObjectReader
```
Interface for object read.
Common specification for object reader and object writer is specified in ObjectWriter. It is recommended to read object writer documentation first before you read this documentation.
An object is readable if the object is a builtin object or its class has the following method.
```
  public static UserClass readObject(ObjectReader r)
 
```
A simple object is read by corresponding read method. The following is an example of reading simple objects.
```
      str = objectReader.readString();
      i = objectReader.readInt();
 
```
A list is read by a beginList() call followed by calls for reading zero or more its elements followed by a end() call.
A map is read by a beginMap() call followed by calls for reading zero or more its elements followed by a end() call.
You can read a custom object indirectly if its class has the following method.
```
  public static UserClass readObject(ObjectReader r)
 
```
When you read a custom object of this class, the readObject method is called. In the method, you must read one equivalent builtin object. It is error to read no object or two or more objects. The method may read on list with multiple elements.
If an exception is thrown during any read call, the reader becomes invalidated. An invalidated reader fails any method.
See Also:

ObjectWriter

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`beginList()`	Reads a list header and begins a list.
`void`	`beginMap()`	Reads a map header and begins a map.
`boolean`	`beginNullableList()`	Reads a nullable list header.
`boolean`	`beginNullableMap()`	Reads a nullable map header.
`void`	`end()`	Ends the current container.
`boolean`	`hasNext()`	Returns true if this reader has next object to read.
`<T> T`	`read(java.lang.Class<T> c)`	Reads an object of the class `c`.
`Address`	`readAddress()`	Reads an address.
`java.math.BigInteger`	`readBigInteger()`	Reads a big integer.
`boolean`	`readBoolean()`	Reads a boolean.
`byte`	`readByte()`	Reads a byte.
`byte[]`	`readByteArray()`	Reads a byte array.
`char`	`readChar()`	Reads a character.
`double`	`readDouble()`	Reads a double.
`float`	`readFloat()`	Reads a float.
`int`	`readInt()`	Reads an integer.
`long`	`readLong()`	Reads a long.
`<T> T`	`readNullable(java.lang.Class<T> c)`	Reads a nullable object.
`<T> T`	`readNullableOrDefault(java.lang.Class<T> c, T def)`	Reads a nullable object or returns default object if there is no next object.
`<T> T`	`readOrDefault(java.lang.Class<T> c, T def)`	Reads an object or returns default object if there is no next object.
`short`	`readShort()`	Reads a short.
`java.lang.String`	`readString()`	Reads a string.
`void`	`skip()`	Skips an element of the current container.
`void`	`skip(int count)`	Skips elements of the current container.

- Method Detail
  - readBoolean
```
boolean readBoolean()
```
    Reads a boolean.
    
    Returns:
    
    the boolean read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readByte
```
byte readByte()
```
    Reads a byte.
    
    Returns:
    
    the byte read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readShort
```
short readShort()
```
    Reads a short.
    
    Returns:
    
    the short read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readChar
```
char readChar()
```
    Reads a character.
    
    Returns:
    
    the char read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readInt
```
int readInt()
```
    Reads an integer.
    
    Returns:
    
    the int read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readFloat
```
float readFloat()
```
    Reads a float.
    
    Returns:
    
    the float read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readLong
```
long readLong()
```
    Reads a long.
    
    Returns:
    
    the long read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readDouble
```
double readDouble()
```
    Reads a double.
    
    Returns:
    
    the double read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readBigInteger
```
java.math.BigInteger readBigInteger()
```
    Reads a big integer.
    
    Returns:
    
    the big integer read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readString
```
java.lang.String readString()
```
    Reads a string.
    
    Returns:
    
    the string read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readByteArray
```
byte[] readByteArray()
```
    Reads a byte array.
    
    Returns:
    
    the byte array read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readAddress
```
Address readAddress()
```
    Reads an address.
    
    Returns:
    
    the address read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - read
```
<T> T read(java.lang.Class<T> c)
```
    Reads an object of the class c.
    Type Parameters:
    
    T - type of object to be read
    
    Parameters:
    
    c - Class of object to be read. It shall be one of Boolean, Byte, Short, Character, Integer, Float, Long, Double, BigInteger, String, byte array, Address, or a custom class with the following method:
    public static UserClass readObject(ObjectReader r)
    
    Returns:
    
    the object read.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.IllegalArgumentException - If the object is not a simple object and correct readObject method is not available or the method threw Throwable which is not an RuntimeException.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
  - readOrDefault
```
<T> T readOrDefault(java.lang.Class<T> c,
                    T def)
```
    Reads an object or returns default object if there is no next object.
    
    Type Parameters:
    
    T - type of object to be read
    
    Parameters:
    
    c - class of object to be read.
    
    def - the default object.
    
    Returns:
    
    the object read or default object.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of type mismatch, corrupted stream or invalidated reader.
    
    java.lang.IllegalArgumentException - If the object is not a simple object and correct readObject method is not available or the method threw Throwable which is not an RuntimeException.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class), hasNext()
  - readNullable
```
<T> T readNullable(java.lang.Class<T> c)
```
    Reads a nullable object.
    
    Type Parameters:
    
    T - type of object to be read
    
    Parameters:
    
    c - class of object to be read.
    
    Returns:
    
    read object or null.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.IllegalArgumentException - If the object is not a simple object and correct readObject method is not available or the method threw Throwable which is not an RuntimeException.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class)
  - readNullableOrDefault
```
<T> T readNullableOrDefault(java.lang.Class<T> c,
                            T def)
```
    Reads a nullable object or returns default object if there is no next object.
    
    Type Parameters:
    
    T - type of object to be read
    
    Parameters:
    
    c - class of object to be read.
    
    def - the default object.
    
    Returns:
    
    read object or null if an object or null is read. Default object if there is no more item in current list or map.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of type mismatch, corrupted stream or invalidated reader.
    
    java.lang.IllegalArgumentException - If the object is not a simple object and correct readObject method is not available or the method threw Throwable which is not an RuntimeException.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    read(Class), hasNext()
  - beginList
```
void beginList()
```
    Reads a list header and begins a list.
    If a list was successfully begun, a read operation reads an element of the list in writing order. After reading zero or more elements, the caller must call end() to end list. It is not required to read all elements before an end() call.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
  - beginNullableList
```
boolean beginNullableList()
```
    Reads a nullable list header. If the reader reads a list header, a list is begun and true is returned. If the reader reads null, no list is begun and false is returned.
    If a list was successfully begun, a read operation reads an element of the list in writing order. After reading zero or more elements, the caller must call end() to end list. It is not required to read all elements before an end() call.
    
    Returns:
    
    true if a list header is read or false if null is read
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    beginList()
  - beginMap
```
void beginMap()
```
    Reads a map header and begins a map.
    If a map was successfully begun, elements of map can be read. A map element consist of a key and its value and can be read by two separate reads and elements are read in writing order. For example, The first read operation after beginning of a map reads the key of the first map element and the next read operation reads it value and the next read operation reads the key of the second element, and so on. After reading keys and values, the caller must call end() to end map. It is not required to read all elements before an end() call.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
  - beginNullableMap
```
boolean beginNullableMap()
```
    Reads a nullable map header. If the reader reads a map header, a map is begun and true is returned. If the reader reads null, no map is begun and false is returned.
    If a map was successfully begun, elements of map can be read. A map element consist of a key and its value and can be read by two separate reads and elements are read in writing order. For example, The first read operation after beginning of a map reads the key of the first map element and the next read operation reads it value and the next read operation reads the key of the second element, and so on. After reading keys and values, the caller must call end() to end map. It is not required to read all elements before an end() call.
    
    Returns:
    
    true if a map header is read or false if null is read
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
    
    See Also:
    
    beginMap()
  - hasNext
```
boolean hasNext()
```
    Returns true if this reader has next object to read. If the reader is reading a container, this method returns true if the top most container has more object to read, returns false otherwise.
    
    Returns:
    
    true if this reader has next object to read.
    
    Throws:
    
    java.lang.IllegalStateException - if this reader was already invalidated.
  - end
```
void end()
```
    Ends the current container. Unread elements of the current container are all skipped.
    
    Throws:
    
    java.lang.IllegalStateException - if this end is imbalanced.
  - skip
```
void skip()
```
    Skips an element of the current container.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).
  - skip
```
void skip(int count)
```
    Skips elements of the current container.
    
    Parameters:
    
    count - the count.
    
    Throws:
    
    java.lang.IllegalStateException - If this reader cannot read the given type of object because of end of stream, end of list, end of map, type mismatch, corrupted stream or invalidated reader.
    
    java.lang.UnsupportedOperationException - If this reader cannot read an object because the object is too long (for example, 2^32 bytes or longer byte array).

Interface ObjectReader

Method Summary

Method Detail

readBoolean

readByte

readShort

readChar

readInt

readFloat

readLong

readDouble

readBigInteger

readString

readByteArray

readAddress

read

readOrDefault

readNullable

readNullableOrDefault

beginList

beginNullableList

beginMap

beginNullableMap

hasNext

end

skip

skip