Package com.nickbenn.room.service

Class Parser

java.lang.Object

com.nickbenn.room.service.Parser

public class Parser
extends Object

Provides a simple parsing service that extracts DDL from a Room-generated JSON schema file. This class is not a Java application (i.e. it does not provide an entry point main method), but is suitable for consumption by many different types of applications or plugins.

The JSON schema produced by Room is structured as shown below. Property values, properties that are not read by this implementation, and repeated properties in arrays are indicated by "..." placeholders.

 {
   "database": {
     "version": ...,
     "entities": [
       {
         "tableName": "...",
         "createSql": "...",
         indices: [
           {
             "name": "...",
             "createSql": "...",
             ...
           },
           ...
         ],
         ...
       },
       ...
     ],
     "views": [
       {
         "viewName": "...",
         "createSql": "..."
       },
       ...
     ],
   },
   ...
 }
 

In general, the SQL fragments in the values of the createSql properties have placeholder tokens referencing the name of the relevant table or view for each. The Entity, Index, and View data-transfer object (DTO) classes replace these placeholders in their implementations of the Streamable.stream() methods.

Constructor Summary

Constructors

Constructor	Description
Parser()	Initializes this instance.

Method Summary

Modifier and Type	Method	Description
void	parse(InputStream input, OutputStream output)	Parses Room schema DDL from JSON content obtained from input, and writes the extracted DDL (with placeholders replaced by the appropriate table and view names) to output.

Methods inherited from class java.lang.Object

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

Constructor Detail

Parser

public Parser()

Initializes this instance. Currently, since this class has no mutable state, nor even any final fields set on instance initialization, this constructor does nothing.

Method Detail

parse

public void parse(InputStream input,
                  OutputStream output)
           throws IOException,
                  JsonIOException,
                  JsonSyntaxException

Parses Room schema DDL from JSON content obtained from input, and writes the extracted DDL (with placeholders replaced by the appropriate table and view names) to output.

Parameters:

input - InputStream source from which Room schema will be read.

output - PrintStream

Throws:

IOException - If unable to read from input or unable to write to output.

JsonIOException - If unable to read JSON from a Reader attached to input.

JsonSyntaxException - If content read from input does not contain valid JSON.