no.petroware.logio.json

Class JsonReader

java.lang.Object

no.petroware.logio.json.JsonReader

public final class JsonReader
extends Object

Class for reading JSON Well Log Format files.

Typical usage:

   JsonReader reader = new JsonReader(new File("path/to/file.json"));
   List<JsonLog> logs = reader.read(true, true, null);
   

If the curve data is not needed, it is possible to read only the metadata. The curve data may be filled in later:

   JsonReader reader = new JsonReader(new File("path/to/file.json"));
   List<JsonLog> logs = reader.read(false, false, null);
   :
   reader.readData(logs);
   

Note that even if only metadata is read, all curve information are properly established as this information comes from metadata. Only the curve values will be missing.

If the JSON content is larger than physical memory, it is possible to stream (process than throw away) the data during read. See JsonDataListener. The same mechanism may be used to abort the reading process during the operation.

Author:

Petroware AS

See Also:

https://jsonwelllogformat.org

Constructor Summary

Constructors

Constructor and Description
JsonReader(File file) Create a JSON reader for the specified disk file.
JsonReader(InputStream inputStream) Create a JSON reader for the specified stream.
JsonReader(javax.json.JsonArray jsonArray) Create a JSON reader from a populated JSON array of JsonLogs.
JsonReader(String text) Create a JSON reader for the specified text.

Method Summary

Modifier and Type	Method and Description
static double	isJsonFile(File file, byte[] content) Get the probability that the specified file is a JSON Well Log Format file.
List<JsonLog>	read() Read all logs from the content of this reader.
List<JsonLog>	read(boolean shouldReadBulkData, boolean shouldCaptureStatistics, JsonDataListener dataListener) Read all logs from the content of this reader.
void	readData(List<JsonLog> logs, boolean shouldCaptureStatistics, JsonDataListener dataListener) Read data for a set of JSON logs where the metadata has already been read.
JsonLog	readOne() Read all logs from the content of this reader and return the first one.

Methods inherited from class java.lang.Object

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

Constructor Detail

JsonReader

public JsonReader(InputStream inputStream)

Create a JSON reader for the specified stream.

Parameters:

inputStream - Stream to read. Non-null.

Throws:

IllegalArgumentException - If inputStream is null.

JsonReader

public JsonReader(File file)

Create a JSON reader for the specified disk file.

Parameters:

file - Disk file to read. Non-null.

Throws:

IllegalArgumentException - If file is null.

JsonReader

public JsonReader(String text)

Create a JSON reader for the specified text.

Parameters:

text - Text to read. Non-null.

Throws:

IllegalArgumentException - If text is null.

JsonReader

public JsonReader(javax.json.JsonArray jsonArray)

Create a JSON reader from a populated JSON array of JsonLogs.

Parameters:

jsonArray - Array constituting the JSON Well Log Format logs. Non-null.

Throws:

IllegalArgumentException - If jsonArray is null.

Method Detail

isJsonFile

public static double isJsonFile(File file,
                                byte[] content)

Get the probability that the specified file is a JSON Well Log Format file.

The check can be done with or without considering the content of the file. In the latter case, only the file name (typically its extension) is considered. In the former case a portion from the start of the file is used to match for known patterns. By passing the portion as an argument, the client code can read this once and then pass it to different classifiers in order to determine its most likely type.

Getting a portion of a file can be done by:

   File file = ...;
   BufferedInputStream stream = new BufferedInputStream(new FileInputStream(file));
   byte[] content = new byte[2000];
   stream.read(content, 0, content.length);
   stream.close();
 

Parameters:

file - File to check. Null to classify on content only.

content - A number of bytes from the start of the file. Null to classify on file name only.

Returns:

Probability that the file is a JSON Well Log file. [0.0,1.0].

readData

public void readData(List<JsonLog> logs,
                     boolean shouldCaptureStatistics,
                     JsonDataListener dataListener)
              throws IOException,
                     InterruptedException

Read data for a set of JSON logs where the metadata has already been read. This will preserve the existing JsonLog structure in case JSON content is read in two operations:

   // Read meta data
   List<JsonLog> logs = reader.read(false, ...);

   // Read the curve data
   reader.readData(logs);
 

There is nothing to gain in performance with this approach so in case the result is not cached, the following will be equivalent:

   // Read metadata
   List<JsonLog> logs = reader.read(false, ...);

   // Read all the data
   logs = reader.read(true, ...);
 

Parameters:

logs - The logs to populate. These must be the exact same list as retrieved by calling the #read(false,...) on the same JsonReader instance. Otherwise the behavior is unpredictable.

shouldCaptureStatistics - True to capture statistics per curve during read. Statistics capture will reduce read performance slightly, so set this to false if the statistics are not needed.

dataListener - Listener that will be notified when new data has been read. Null if not used.

Throws:

IllegalArgumentException - If logs is null.

IOException - If the read operation fails for some reason.

InterruptedException - If the client returns false from the JsonDataListener.dataRead(no.petroware.logio.json.JsonLog) method.

read

public List<JsonLog> read(boolean shouldReadBulkData,
                          boolean shouldCaptureStatistics,
                          JsonDataListener dataListener)
                   throws IOException,
                          InterruptedException

Read all logs from the content of this reader.

Parameters:

shouldReadBulkData - True if bulk data should be read, false if only metadata should be read.

shouldCaptureStatistics - True if curve statistics should be captures, false otherwise,

dataListener - Client data listener. Null if not used.

Returns:

The logs of the JSON stream. Never null.

Throws:

IOException - If the read operation fails for some reason.

InterruptedException - If the client returns false from the JsonDataListener.dataRead(no.petroware.logio.json.JsonLog) method.

read

public List<JsonLog> read()
                   throws IOException

Read all logs from the content of this reader.

Returns:

The logs of the JSON stream. Never null.

Throws:

IOException - If the read operation fails for some reason.

readOne

public JsonLog readOne()
                throws IOException

Read all logs from the content of this reader and return the first one. This is a convenience method if the client knows that the source contains exactly one log.

Returns:

The first log of the JSON stream. Null if there is none.

Throws:

IOException - If the read operation fails for some reason.