com.exalead.papi.helper.io

Class ExternalizableUtils

java.lang.Object

com.exalead.papi.helper.io.ExternalizableUtils

public class ExternalizableUtils
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
static java.nio.charset.Charset	UTF8

Constructor Summary

Constructors

Constructor and Description
ExternalizableUtils()

Method Summary

Modifier and Type	Method and Description
static void	copyStream(java.io.DataInput in, java.io.DataOutput out)
static java.math.BigInteger	readBigInteger(java.io.DataInput in) Reads an BigInteger from the input stream, the structure is such as: A boolean to tell if the value is null or not.
static java.lang.Boolean	readBoolean(java.io.DataInput in) Reads a Boolean to the input stream, the structure is such as: A boolean to tell if the value is null or not.
static void	readDocument(java.io.DataInput in, DocumentHandler handler) Reads a document from the input stream.
static int	readDocumentList(java.io.DataInput ins, DocumentListHandler handler)
static <T extends java.lang.Enum<T>> T	readEnum(java.io.DataInput in, java.lang.Class<T> cls) Reads an enumeration from the input stream.
static int[]	readIntArray(java.io.DataInput in) Reads an integer array to the output stream, the structure is such as: An integer (DataOutput.writeInt(int)) to tell if the size of the array.
static java.lang.Integer	readInteger(java.io.DataInput in) Reads an Integer to the input stream, the structure is such as: A boolean to tell if the value is null or not.
static java.util.List<java.lang.Integer>	readIntList(java.io.DataInput in) Reads an integer array and exposes it as if it was a integer list
static int	readKeyValueContainer(java.io.DataInput in, DirectiveHandler handler) Read the content of a KeyValuesContainer.
static java.lang.Long	readLong(java.io.DataInput in) Reads an Long to the input stream, the structure is such as: A boolean to tell if the value is null or not.
static int	readMetaContainer(java.io.DataInput in, MetaHandler handler) Reads a meta container.
static int	readPartContainer(java.io.DataInput in, PartContainerHandler handler) Reads a PartContainer from the input stream The IOCallbackHandler.endHandler() is always invoked, weither the container was null or not.
static void	readStream(java.io.DataInput ins, PartHandler handler) Reads a stream for a part.
static java.lang.String	readString(java.io.DataInput in) Reads an String from the input stream, the structure is such as: A boolean to tell if the value is null or not.
static java.lang.String[]	readStringArray(java.io.DataInput in) Reads an String array to the output stream, the structure is such as: An integer (DataOutput.writeInt(int)) to tell if the size of the array.
static java.util.List<java.lang.String>	readStringList(java.io.DataInput in) Reads a String array and exposes it as if it was a String list
static java.lang.String[][]	readStringMatrix(java.io.DataInput in)
static void	writeBigInteger(java.io.DataOutput out, java.math.BigInteger i) Writes an BigInteger to the output stream, the structure is such as: A boolean to tell if the value is null or not.
static void	writeBoolean(java.io.DataOutput out, java.lang.Boolean b) Writes a Boolean to the output stream, the structure is such as: A boolean to tell if the value is null or not.
static void	writeDocument(java.io.DataOutput out, Document doc) Writes a document to the output stream.
static void	writeDocumentList(java.io.DataOutput outs, Document[] docList)
static void	writeEnum(java.io.DataOutput out, java.lang.Enum<?> enumeration) The structure is such as: A boolean to tell if the value is null (false) or not.
static void	writeIntArray(java.io.DataOutput out, int[] intList) Writes an integer array to the output stream, the structure is such as: An integer (DataOutput.writeInt(int)) to tell if the size of the array.
static void	writeInteger(java.io.DataOutput out, java.lang.Integer i) Writes a Integer to the output stream, the structure is such as: A boolean to tell if the value is null or not.
static void	writeIntList(java.io.DataOutput out, java.util.List<java.lang.Integer> intList) Writes an integer list as if it was a integer array.
static void	writeKeyValueContainer(java.io.DataOutput out, KeyValuesContainer<java.lang.String,java.lang.String> kvContainer) Writes the content of a KeyValuesContainer.
static void	writeLong(java.io.DataOutput out, java.lang.Long l) Writes a Long to the output stream, the structure is such as: A boolean to tell if the value is null or not.
static void	writeMetaContainer(java.io.DataOutput out, MetaContainer container) A meta container is written such as: If there is another meta in the meta container, sends true.
static void	writePartContainer(java.io.DataOutput out, PartContainer pc) Writes a part container.
static void	writeStream(java.io.DataOutput out, ContentStream stream) Writes the content of a ContentStream.
static void	writeString(java.io.DataOutput out, java.lang.String str) Writes an String to the output stream, the structure is such as: A boolean to tell if the value is null or not.
static void	writeStringArray(java.io.DataOutput out, java.lang.String[] str) Writes an String array to the output stream, the structure is such as: An integer (DataOutput.writeInt(int)) to tell if the size of the array.
static void	writeStringList(java.io.DataOutput out, java.util.List<java.lang.String> str) Writes an String list as if it was a string array.
static void	writeStringMatrix(java.io.DataOutput out, java.lang.String[][] str)

Methods inherited from class java.lang.Object

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

Field Detail

UTF8

public static final java.nio.charset.Charset UTF8

Constructor Detail

ExternalizableUtils

public ExternalizableUtils()

Method Detail

readBoolean

public static java.lang.Boolean readBoolean(java.io.DataInput in)
                                     throws java.io.IOException

Reads a Boolean to the input stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns null
2. If the value is not null, reads the boolean value with DataInput.readBoolean()

Parameters:

in - The stream to read from

Returns:

a Boolean value, either null, Boolean#FALSE or Boolean#TRUE

Throws:

java.io.IOException

writeBoolean

public static void writeBoolean(java.io.DataOutput out,
                                java.lang.Boolean b)
                         throws java.io.IOException

Writes a Boolean to the output stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns without sending anymore data
2. If the value is not null, writes the boolean value with DataOutput.writeBoolean(boolean)

Parameters:

out - The stream to write to

b - The value to write

Throws:

java.io.IOException

readInteger

public static java.lang.Integer readInteger(java.io.DataInput in)
                                     throws java.io.IOException

Reads an Integer to the input stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns null
2. If the value is not null, reads the integer value with DataInput.readInt()

Parameters:

in - The stream to read from

Returns:

a Integer value, (either null, or an Integer value

Throws:

java.io.IOException

writeInteger

public static void writeInteger(java.io.DataOutput out,
                                java.lang.Integer i)
                         throws java.io.IOException

Writes a Integer to the output stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns without sending anymore data
2. If the value is not null, writes the int value with DataOutput.writeInt(int)

Parameters:

out - the stream to write to

b - the value to write

Throws:

java.io.IOException

readBigInteger

public static java.math.BigInteger readBigInteger(java.io.DataInput in)
                                           throws java.io.IOException

Reads an BigInteger from the input stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns null
2. If the value is not null, reads the big integer into as a byte array
   1. Reads the size of the big integer: DataInput.readInt()
   2. Fully reads the byte array: DataInput.readFully(byte[])
   3. Instantiate and returns the big integer out of the byte array

Parameters:

in - The stream to read from

Returns:

a Integer value, (either null, or an Integer value

Throws:

java.io.IOException

writeBigInteger

public static void writeBigInteger(java.io.DataOutput out,
                                   java.math.BigInteger i)
                            throws java.io.IOException

Writes an BigInteger to the output stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns without sending anything more
2. If the value is not null, turns the big integer into a byte array BigInteger.toByteArray() then writes it:
   1. Writes the size of the byte array: DataOutput.writeInt(int)
   2. Writes the byte array DataOutput.write(byte[])

Parameters:

out -

i -

Throws:

java.io.IOException

readLong

public static java.lang.Long readLong(java.io.DataInput in)
                               throws java.io.IOException

Reads an Long to the input stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns null
2. If the value is not null, reads the integer value with DataInput.readLong()

Parameters:

in - The stream to read from

Returns:

a Long value, (either null, or a Long instance

Throws:

java.io.IOException

writeLong

public static void writeLong(java.io.DataOutput out,
                             java.lang.Long l)
                      throws java.io.IOException

Writes a Long to the output stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns without sending anymore data
2. If the value is not null, writes the int value with DataOutput.writeLong(long)

Parameters:

out - the stream to write to

l - the value to write

Throws:

java.io.IOException

readString

public static java.lang.String readString(java.io.DataInput in)
                                   throws java.io.IOException

Reads an String from the input stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null returns null
2. If not null the value of the string as an UTF-8 byte array
   1. An integer for the size of the byte array DataInput.readInt()
   2. The byte array: DataInput.readFully(byte[])

Parameters:

in - The stream to read from

Returns:

a Long value, (either null, or a Long instance

Throws:

java.io.IOException

writeString

public static void writeString(java.io.DataOutput out,
                               java.lang.String str)
                        throws java.io.IOException

Writes an String to the output stream, the structure is such as:

1. A boolean to tell if the value is null or not. If it is null writes false with DataOutput.writeBoolean(boolean) and returns.
2. If not null the value of the string as an UTF-8 byte array
   1. An integer for the size of the byte array DataOutput.writeInt(int)
   2. The byte array: DataOutput.write(byte[])

Parameters:

out -

str -

Throws:

java.io.IOException

readStringArray

public static java.lang.String[] readStringArray(java.io.DataInput in)
                                          throws java.io.IOException

Reads an String array to the output stream, the structure is such as:

1. An integer (DataOutput.writeInt(int)) to tell if the size of the array. If less than 0 then the array is null, then returns null.
2. If not null, reads as many strings as the size of the array with readString(DataInput)

n

Returns:

Throws:

java.io.IOException

writeStringArray

public static void writeStringArray(java.io.DataOutput out,
                                    java.lang.String[] str)
                             throws java.io.IOException

Writes an String array to the output stream, the structure is such as:

1. An integer (DataOutput.writeInt(int)) to tell if the size of the array. If less than 0 then the array is null, then returns without sending anything else.
2. If not null, write as many strings as the size of the array with writeString(DataOutput, String)

Parameters:

out - The destination stream

str - the value to write

Throws:

java.io.IOException

readStringMatrix

public static java.lang.String[][] readStringMatrix(java.io.DataInput in)
                                             throws java.io.IOException

Throws:

java.io.IOException

writeStringMatrix

public static void writeStringMatrix(java.io.DataOutput out,
                                     java.lang.String[][] str)
                              throws java.io.IOException

Throws:

java.io.IOException

readStringList

public static java.util.List<java.lang.String> readStringList(java.io.DataInput in)
                                                       throws java.io.IOException

Reads a String array and exposes it as if it was a String list

Parameters:

in -

Returns:

A string list (may be null)

Throws:

java.io.IOException

See Also:

ExternalizableUtils#readStringArray(DataInput)}

writeStringList

public static void writeStringList(java.io.DataOutput out,
                                   java.util.List<java.lang.String> str)
                            throws java.io.IOException

Writes an String list as if it was a string array.

Parameters:

out - The destination stream

str - the value to write

Throws:

java.io.IOException

See Also:

ExternalizableUtils#writeStringArray(DataOutput, String[])}

readIntArray

public static int[] readIntArray(java.io.DataInput in)
                          throws java.io.IOException

Reads an integer array to the output stream, the structure is such as:

1. An integer (DataOutput.writeInt(int)) to tell if the size of the array. If less than 0 then the array is null, then returns null.
2. If not null, reads as many integers as the size of the array with DataInput.readInt()

n

Returns:

Throws:

java.io.IOException

writeIntArray

public static void writeIntArray(java.io.DataOutput out,
                                 int[] intList)
                          throws java.io.IOException

Writes an integer array to the output stream, the structure is such as:

1. An integer (DataOutput.writeInt(int)) to tell if the size of the array. If less than 0 then the array is null, then returns without sending anything else.
2. If not null, write as many strings as the size of the array with DataOutput.write(int)

Parameters:

out - The destination stream

intList - the value to write

Throws:

java.io.IOException

readIntList

public static java.util.List<java.lang.Integer> readIntList(java.io.DataInput in)
                                                     throws java.io.IOException

Reads an integer array and exposes it as if it was a integer list

Parameters:

in -

Returns:

A integer list (may be null)

Throws:

java.io.IOException

See Also:

ExternalizableUtils#readIntArray(DataInput)}

writeIntList

public static void writeIntList(java.io.DataOutput out,
                                java.util.List<java.lang.Integer> intList)
                         throws java.io.IOException

Writes an integer list as if it was a integer array.

Parameters:

out - The destination stream

intList - the value to write

Throws:

java.io.IOException

See Also:

ExternalizableUtils#writeIntArray(DataOutput, int[])}

readKeyValueContainer

public static int readKeyValueContainer(java.io.DataInput in,
                                        DirectiveHandler handler)
                                 throws java.lang.Exception

Read the content of a KeyValuesContainer. The IOCallbackHandler.endHandler() is always invoked, weither the container was null or not. The structure of the directive container is such as:

1. Reads a boolean to tell if there is a name/value couple
2. If there is another key/value pair
   1. Reads the key with readString(DataInput)
   2. Reads the values readStringList(DataInput)

Parameters:

in -

handler - the consumer of each key-value pair

Returns:

the number of key/value pair of the container

Throws:

java.lang.Exception

writeKeyValueContainer

public static void writeKeyValueContainer(java.io.DataOutput out,
                                          KeyValuesContainer<java.lang.String,java.lang.String> kvContainer)
                                   throws java.io.IOException

Writes the content of a KeyValuesContainer. The structure of the directive container is such as:

1. Writes a boolean to tell if there is a name/value couple. If null write a false an returns
2. If there is another key/value pair
   1. Writes the key with writeString(DataOutput, String)
   2. Writes the values writeStringList(DataOutput, List)

Parameters:

out -

kvContainer -

Throws:

java.io.IOException

readEnum

public static <T extends java.lang.Enum<T>> T readEnum(java.io.DataInput in,
                                                       java.lang.Class<T> cls)
                                                throws java.io.IOException

Reads an enumeration from the input stream. The structure is such as:

1. A boolean to tell if the value is null (false) or not
2. If not null, reads the name of the enumeration and instantiate it with Enum.valueOf(Class, String)

Parameters:

in -

cls - The class of the expected enumeration

Returns:

Throws:

java.io.IOException

writeEnum

public static void writeEnum(java.io.DataOutput out,
                             java.lang.Enum<?> enumeration)
                      throws java.io.IOException

The structure is such as:

1. A boolean to tell if the value is null (false) or not. If null returns
2. If not null, writes the name (Enum.name()) of the enumeration

Parameters:

out -

enumeration -

Throws:

java.io.IOException

readStream

public static void readStream(java.io.DataInput ins,
                              PartHandler handler)
                       throws java.lang.Exception

Reads a stream for a part. The structure of a stream is

1. a long, the size of the stream
2. as many bytes as the of the size

Parameters:

ins -

handler - The part handler, cannot be null

Throws:

java.lang.Exception

writeStream

public static void writeStream(java.io.DataOutput out,
                               ContentStream stream)
                        throws java.io.IOException

Writes the content of a ContentStream.

• If the value of ContentStream.getStreamLength() if less than 0 (which means that the size of the stream is unknown) the stream is completely read once (into a black hole) to know the exact number of bytes of the stream. Then the stream will re re-read once more to write its content
• If the value of ContentStream.getStreamLength() is greater or equal to 0, then exactly that number of bytes will be written. If the stream contains less than heralded, an error is raised. If the stream contains more, this is ignored.

The written structure is such as:

1. Writes a long being the size of the stream. If the stream is null writes 0.
2. Writes the content of the stream

Parameters:

out -

stream -

Throws:

java.io.IOException

copyStream

public static void copyStream(java.io.DataInput in,
                              java.io.DataOutput out)
                       throws java.io.IOException

Parameters:

in - The input stream. It is structured such as:

1. long, the size of the stream. Must be equal or greater than 0
2. A stream of data that must be exactly the number of bytes heralded by the previous long

out - The destination stream

Throws:

java.io.IOException - IF failed to read the source or to write to the destination stream

readMetaContainer

public static int readMetaContainer(java.io.DataInput in,
                                    MetaHandler handler)
                             throws java.lang.Exception

Reads a meta container.

1. boolean, if true there is another meta in the meta container. If false, there is no more Meta and we are finished with this meta container
2. If there is another meta
   1. The first string is the meta name
   2. The second string is the meta value

The IOCallbackHandler.endHandler() is always invoked, weither the container was null or not.

Parameters:

in - The source to read a Meta container from. A meta container is a list of meta, it is structure such as: The string are read by readString(DataInput)

handler - The processor of the meta (for each meta in the meta container)

Returns:

The number of meta(s) in the meta container

Throws:

java.lang.Exception

writeMetaContainer

public static void writeMetaContainer(java.io.DataOutput out,
                                      MetaContainer container)
                               throws java.io.IOException

A meta container is written such as:

1. If there is another meta in the meta container, sends true. Sends false and returns.
2. If there is another meta:
   1. Writes the meta name as a string
   2. Writes the meta value as a string

The strings are written using writeString(DataOutput, String)

Parameters:

out - The stream to write a meta container to.

container - to copy to the output stream

Throws:

java.io.IOException

readPartContainer

public static int readPartContainer(java.io.DataInput in,
                                    PartContainerHandler handler)
                             throws java.lang.Exception

Reads a PartContainer from the input stream The IOCallbackHandler.endHandler() is always invoked, weither the container was null or not. For the structure, see writePartContainer(DataOutput, PartContainer)

Parameters:

in -

handler -

Returns:

The number of parts in the container

Throws:

java.lang.Exception

writePartContainer

public static void writePartContainer(java.io.DataOutput out,
                                      PartContainer pc)
                               throws java.io.IOException

Writes a part container. The strcuture is such as:

1. A boolean DataOutput.writeBoolean(boolean) to tell if there is more part to send. If there is no more parts, emit false and returns
2. If there is more parts, then writes:
   1. The name of the part: writeString(DataOutput, String)
   2. The directives of the part: writeKeyValueContainer(DataOutput, KeyValuesContainer)
   3. The content of the part: writeStream(DataOutput, ContentStream)

Parameters:

out -

pc - the part container to write to the stream

Throws:

java.io.IOException

readDocument

public static void readDocument(java.io.DataInput in,
                                DocumentHandler handler)
                         throws java.lang.Exception

Reads a document from the input stream. There is the assumption that the document to read is not null. The IOCallbackHandler.endHandler() is always invoked. For the structure, see writeDocument(DataOutput, Document)

Parameters:

in -

handler - The handler to process the document. Cannot be null

Throws:

java.lang.Exception

writeDocument

public static void writeDocument(java.io.DataOutput out,
                                 Document doc)
                          throws java.lang.Exception

Writes a document to the output stream.

1. Writes the URI: writeString(DataOutput, String)
2. Writes the stamp: writeString(DataOutput, String)
3. Writes the directives of the document: writeKeyValueContainer(DataOutput, KeyValuesContainer)
4. Writes the meta container: writeMetaContainer(DataOutput, MetaContainer)
5. Writes the part container: writePartContainer(DataOutput, PartContainer)

Parameters:

out -

doc - The document to send. Must be not null

Throws:

java.lang.Exception

writeDocumentList

public static void writeDocumentList(java.io.DataOutput outs,
                                     Document[] docList)
                              throws java.lang.Exception

Throws:

java.lang.Exception

readDocumentList

public static int readDocumentList(java.io.DataInput ins,
                                   DocumentListHandler handler)
                            throws java.io.IOException,
                                   java.lang.Exception

Throws:

java.io.IOException

java.lang.Exception