SQOOP-12. Alternate NULL formats.

This fix allows the user to optionally specify different null
representations. It addresses both the import and export use
cases, in addition to both string and non-string column types.

From: Ahmed Radwan <ahmed@cloudera.com>

git-svn-id: https://svn.apache.org/repos/asf/incubator/sqoop/trunk@1149996 13f79535-47bb-0310-9956-ffa450edef68

src/docs/man/sqoop-export.txt

@@ -43,6 +43,12 @@ Export control options
 --update-key (col-name)::
   Anchor column to use for updates
 
+--input-null-string::
+  The string to be interpreted as null for string columns
+
+--input-null-non-string::
+  The string to be interpreted as null for non-string columns
+
 include::input-args.txt[]
 
 include::output-args.txt[]

src/docs/man/sqoop-import.txt

@@ -75,6 +75,11 @@ Import control options
 -z::
   Uses gzip to compress data as it is written to HDFS
 
+--null-string::
+  The string to be written for a null value for string columns
+
+--null-non-string::
+  The string to be written for a null value for non-string columns
 
 include::output-args.txt[]
 

src/docs/user/export.txt

@@ -43,15 +43,20 @@ include::common-args.txt[]
 
 .Export control arguments:
 [grid="all"]
-`---------------------------`------------------------------------------
+`----------------------------------------`------------------------------
 Argument                                 Description
------------------------------------------------------------------------
+------------------------------------------------------------------------
 +\--direct+                              Use direct export fast path
 +\--export-dir <dir>+                    HDFS source path for the export
-+-m,\--num-mappers <n>+     Use 'n' map tasks to export in parallel
++-m,\--num-mappers <n>+                  Use 'n' map tasks to export in\
+                                         parallel
 +\--table <table-name>+                  Table to populate
 +\--update-key <col-name>+               Anchor column to use for updates
------------------------------------------------------------------------
++\--input-null-string <null-string>+     The string to be interpreted as\
+                                         null for string columns
++\--input-null-non-string <null-string>+ The string to be interpreted as\
+                                         null for non-string columns
+------------------------------------------------------------------------
 
 The +\--table+ and +\--export-dir+ arguments are required. These
 specify the table to populate in the database, and the
@@ -73,6 +78,14 @@ MySQL provides a direct mode for exports as well, using the
 to specify this codepath. This may be
 higher-performance than the standard JDBC codepath. 
 
+The +\--input-null-string+ and +\--input-null-non-string+ arguments are
+optional. If +\--input-null-string+ is not specified, then the string
+"null" will be interpreted as null for string-type columns.
+If +\--input-null-non-string+ is not specified, then both the string
+"null" and the empty string will be interpreted as null for non-string
+columns. Note that, the empty string will be always interpreted as null
+for non-string columns, in addition to other string if specified by
++\--input-null-non-string+.
 
 Inserts vs. Updates
 ~~~~~~~~~~~~~~~~~~~

src/docs/user/import.txt

@@ -49,9 +49,9 @@ include::connecting.txt[]
 
 .Import control arguments:
 [grid="all"]
-`-----------------------------`--------------------------------------
+`---------------------------------`--------------------------------------
 Argument                          Description
----------------------------------------------------------------------
+-------------------------------------------------------------------------
 +\--append+                       Append data to an existing dataset\
                                   in HDFS
 +\--as-sequencefile+              Imports data to SequenceFiles
@@ -70,9 +70,14 @@ Argument                      Description
 +\--warehouse-dir <dir>+          HDFS parent for table destination
 +\--where <where clause>+         WHERE clause to use during import
 +-z,\--compress+                  Enable compression
----------------------------------------------------------------------
++--null-string <null-string>+     The string to be written for a null\
-
+                                  value for string columns
++--null-non-string <null-string>+ The string to be written for a null\
+                                  value for non-string columns
+-------------------------------------------------------------------------
 
+The +\--null-string+ and +\--null-non-string+ arguments are optional.\
+If not specified, then the string "null" will be used.
 
 Selecting the Data to Import
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/java/com/cloudera/sqoop/SqoopOptions.java

@@ -114,6 +114,12 @@ public enum IncrementalMode {
   // used. If so, it is stored as 'db.password'.
   private String password;
 
+  @StoredAsProperty("null.string") private String nullStringValue;
+  @StoredAsProperty("input.null.string") private String inNullStringValue;
+  @StoredAsProperty("null.non-string") private String nullNonStringValue;
+  @StoredAsProperty("input.null.non-string")
+      private String inNullNonStringValue;
+
   @StoredAsProperty("codegen.output.dir") private String codeOutputDir;
   @StoredAsProperty("codegen.compile.dir") private String jarOutputDir;
   // Boolean specifying whether jarOutputDir is a nonce tmpdir (true), or
@@ -1597,5 +1603,37 @@ public String getConnManagerClassName() {
     return connManagerClassName;
   }
 
+  public void setNullStringValue(String nullString) {
+    this.nullStringValue = nullString;
+  }
+
+  public String getNullStringValue() {
+    return nullStringValue;
+  }
+
+  public void setInNullStringValue(String inNullString) {
+    this.inNullStringValue = inNullString;
+  }
+
+  public String getInNullStringValue() {
+    return inNullStringValue;
+  }
+
+public void setNullNonStringValue(String nullNonString) {
+    this.nullNonStringValue = nullNonString;
+}
+
+public String getNullNonStringValue() {
+    return nullNonStringValue;
+}
+
+public void setInNullNonStringValue(String inNullNonString) {
+    this.inNullNonStringValue = inNullNonString;
+}
+
+public String getInNullNonStringValue() {
+    return inNullNonStringValue;
+}
+
 }
 

src/java/com/cloudera/sqoop/orm/ClassWriter.java

@@ -272,10 +272,17 @@ private String dbSetterForType(String javaType) {
 
   private String stringifierForType(String javaType, String colName) {
     if (javaType.equals("String")) {
-      return colName;
+      // Check if it is null, and write the null representation in such case
+      String r = colName  + "==null?\"" + this.options.getNullStringValue()
+          + "\":" + colName;
+      return r;
     } else {
       // This is an object type -- just call its toString() in a null-safe way.
-      return "\"\" + " + colName;
+      // Also check if it is null, and instead write the null representation
+      // in such case
+      String r = colName  + "==null?\"" + this.options.getNullNonStringValue()
+          + "\":" + "\"\" + " + colName;
+      return r;
     }
   }
 
@@ -731,17 +738,19 @@ private void generateParseMethod(String typ, StringBuilder sb) {
   }
 
   /**
-   * Helper method for parseColumn(). Interpret the string 'null' as a null
+   * Helper method for parseColumn(). Interpret the string null representation
    * for a particular column.
    */
   private void parseNullVal(String javaType, String colName, StringBuilder sb) {
     if (javaType.equals("String")) {
-      sb.append("    if (__cur_str.equals(\"null\")) { this.");
+      sb.append("    if (__cur_str.equals(\""
+         + this.options.getInNullStringValue() + "\")) { this.");
       sb.append(colName);
       sb.append(" = null; } else {\n");
     } else {
-      sb.append("    if (__cur_str.equals(\"null\")");
+      sb.append("    if (__cur_str.equals(\""
-      sb.append(" || __cur_str.length() == 0) { this.");
+         + this.options.getInNullNonStringValue());
+      sb.append("\") || __cur_str.length() == 0) { this.");
       sb.append(colName);
       sb.append(" = null; } else {\n");
     }

src/java/com/cloudera/sqoop/tool/BaseSqoopTool.java

@@ -77,6 +77,10 @@ public abstract class BaseSqoopTool extends SqoopTool {
   public static final String WAREHOUSE_DIR_ARG = "warehouse-dir";
   public static final String TARGET_DIR_ARG = "target-dir";
   public static final String APPEND_ARG = "append";  
+  public static final String NULL_STRING = "null-string";
+  public static final String INPUT_NULL_STRING = "input-null-string";
+  public static final String NULL_NON_STRING = "null-non-string";
+  public static final String INPUT_NULL_NON_STRING = "input-null-non-string";
 
   public static final String FMT_SEQUENCEFILE_ARG = "as-sequencefile";
   public static final String FMT_TEXTFILE_ARG = "as-textfile";
@@ -493,6 +497,26 @@ protected RelatedOptions getCodeGenOpts(boolean multiTable) {
         .withDescription("Put auto-generated classes in this package")
         .withLongOpt(PACKAGE_NAME_ARG)
         .create());
+    codeGenOpts.addOption(OptionBuilder.withArgName("null-string")
+            .hasArg()
+            .withDescription("Null string representation")
+            .withLongOpt(NULL_STRING)
+            .create());
+    codeGenOpts.addOption(OptionBuilder.withArgName("input-null-string")
+            .hasArg()
+            .withDescription("Input null string representation")
+            .withLongOpt(INPUT_NULL_STRING)
+            .create());
+    codeGenOpts.addOption(OptionBuilder.withArgName("null-non-string")
+            .hasArg()
+            .withDescription("Null non-string representation")
+            .withLongOpt(NULL_NON_STRING)
+            .create());
+    codeGenOpts.addOption(OptionBuilder.withArgName("input-null-non-string")
+            .hasArg()
+            .withDescription("Input null non-string representation")
+            .withLongOpt(INPUT_NULL_NON_STRING)
+            .create());
     if (!multiTable) {
       codeGenOpts.addOption(OptionBuilder.withArgName("name")
           .hasArg()
@@ -563,6 +587,22 @@ protected void applyCommonOptions(CommandLine in, SqoopOptions out)
         out.setConnManagerClassName(in.getOptionValue(CONN_MANAGER_CLASS_NAME));
     }
 
+    if (in.hasOption(NULL_STRING)) {
+        out.setNullStringValue(in.getOptionValue(NULL_STRING));
+    }
+
+    if (in.hasOption(INPUT_NULL_STRING)) {
+        out.setInNullStringValue(in.getOptionValue(INPUT_NULL_STRING));
+    }
+
+    if (in.hasOption(NULL_NON_STRING)) {
+        out.setNullNonStringValue(in.getOptionValue(NULL_NON_STRING));
+    }
+
+    if (in.hasOption(INPUT_NULL_NON_STRING)) {
+        out.setInNullNonStringValue(in.getOptionValue(INPUT_NULL_NON_STRING));
+    }
+
     if (in.hasOption(DRIVER_ARG)) {
       out.setDriverClassName(in.getOptionValue(DRIVER_ARG));
     }