io.permazen.kv.util

Class XMLSerializer

java.lang.Object

io.permazen.util.AbstractXMLStreaming

io.permazen.kv.util.XMLSerializer

public class XMLSerializer
extends AbstractXMLStreaming

Utility methods for serializing and deserializing the contents of a KVStore to/from XML.

The XML has a simple format; empty values may be omitted:

  <xml version="1.0" encoding="UTF-8"?>

  <entries>
      <entry>
          <key>013f7b</key>
          <value>5502</value>
      </entry>
      <entry>
          <key>ee7698</key>
      </entry>
      ...
  </entries>
  

Field Summary

Fields

Modifier and Type	Field and Description
static QName	ENTRIES_TAG
static QName	ENTRY_TAG
static QName	KEY_TAG
static QName	VALUE_TAG

Constructor Summary

Constructors

Constructor and Description
XMLSerializer(KVStore kv) Constructor.

Method Summary

Modifier and Type	Method and Description
int	read(InputStream input) Import key/value pairs into the KVStore associated with this instance from the given XML input.
int	read(XMLStreamReader reader) Import key/value pairs into the KVStore associated with this instance from the given XML input.
int	write(OutputStream output, boolean indent) Export all key/value pairs from the KVStore associated with this instance to the given output.
int	write(Writer writer, boolean indent) Export all key/value pairs from the KVStore associated with this instance to the given writer.
int	write(XMLStreamWriter writer, byte[] minKey, byte[] maxKey) Export a range of key/value pairs from the KVStore associated with this instance to the given XML output.

Methods inherited from class io.permazen.util.AbstractXMLStreaming

expect, expectClose, getAttr, getAttr, getBooleanAttr, getBooleanAttr, getIntAttr, getIntAttr, getLongAttr, newInvalidAttributeException, next, skip, writeElement

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ENTRIES_TAG

public static final QName ENTRIES_TAG

ENTRY_TAG

public static final QName ENTRY_TAG

KEY_TAG

public static final QName KEY_TAG

VALUE_TAG

public static final QName VALUE_TAG

Constructor Detail

XMLSerializer

public XMLSerializer(KVStore kv)

Constructor.

Parameters:

kv - key/value store on which to operate

Throws:

IllegalArgumentException - if kv is null

Method Detail

read

public int read(InputStream input)
         throws XMLStreamException

Import key/value pairs into the KVStore associated with this instance from the given XML input.

The input is not closed by this method.

Parameters:

input - XML input

Returns:

the number of key/value pairs read

Throws:

XMLStreamException - if an error occurs

IllegalArgumentException - if input is null

read

public int read(XMLStreamReader reader)
         throws XMLStreamException

Import key/value pairs into the KVStore associated with this instance from the given XML input. This method expects to see an opening <entries> as the next event (not counting whitespace, comments, etc.), which is then consumed up through the closing </entries> event. The reader is not closed by this method. Therefore, this tag could be part of a larger XML document.

Parameters:

reader - XML reader

Returns:

the number of key/value pairs read

Throws:

XMLStreamException - if an error occurs

IllegalArgumentException - if reader is null

write

public int write(OutputStream output,
                 boolean indent)
          throws XMLStreamException

Export all key/value pairs from the KVStore associated with this instance to the given output.

The output is not closed by this method.

Parameters:

output - XML output; will not be closed by this method

indent - true to indent output, false for all on one line

Returns:

the number of key/value pairs written

Throws:

XMLStreamException - if an error occurs

IllegalArgumentException - if output is null

write

public int write(Writer writer,
                 boolean indent)
          throws XMLStreamException

Export all key/value pairs from the KVStore associated with this instance to the given writer.

The writer is not closed by this method.

Parameters:

writer - XML output; will not be closed by this method

indent - true to indent output, false for all on one line

Returns:

the number of key/value pairs written

Throws:

XMLStreamException - if an error occurs

IllegalArgumentException - if writer is null

write

public int write(XMLStreamWriter writer,
                 byte[] minKey,
                 byte[] maxKey)
          throws XMLStreamException

Export a range of key/value pairs from the KVStore associated with this instance to the given XML output.

This method writes a start element as its first action, allowing the output to be embedded into a larger XML document. Callers not embedding the output may with to precede invocation of this method with a call to writer.writeStartDocument().

The writer is not closed by this method.

Parameters:

writer - XML writer; will not be closed by this method

minKey - minimum key (inclusive), or null for none

maxKey - maximum key (exclusive), or null for none

Returns:

the number of key/value pairs written

Throws:

XMLStreamException - if an error occurs

IllegalArgumentException - if writer is null