fix: ResultSet#get(...) methods should auto convert values (#143)

* fix: ResultSet#get(...) methods should auto convert values

* tests: add additional tests

* tests: add more conversion tests

* tests: add more timestamp tests

* tests: add timestamp tests

* review: process review comments

Author: olavloite

src/main/java/com/google/cloud/spanner/jdbc/AbstractJdbcWrapper.java

@@ -22,9 +22,11 @@
 import java.sql.Date;
 import java.sql.SQLException;
 import java.sql.SQLFeatureNotSupportedException;
+import java.sql.Time;
 import java.sql.Timestamp;
 import java.sql.Types;
 import java.sql.Wrapper;
+import java.util.Calendar;
 
 /** Base class for all Cloud Spanner JDBC classes that implement the {@link Wrapper} interface. */
 abstract class AbstractJdbcWrapper implements Wrapper {
@@ -147,6 +149,126 @@ static float checkedCastToFloat(double val) throws SQLException {
     return (float) val;
   }
 
+  /**
+   * Parses the given string value as a long. Throws {@link SQLException} if the string is not a
+   * valid long value.
+   */
+  static long parseLong(String val) throws SQLException {
+    Preconditions.checkNotNull(val);
+    try {
+      return Long.valueOf(val);
+    } catch (NumberFormatException e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid number", val), com.google.rpc.Code.INVALID_ARGUMENT, e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a double. Throws {@link SQLException} if the string is not a
+   * valid double value.
+   */
+  static double parseDouble(String val) throws SQLException {
+    Preconditions.checkNotNull(val);
+    try {
+      return Double.valueOf(val);
+    } catch (NumberFormatException e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid number", val), com.google.rpc.Code.INVALID_ARGUMENT, e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a {@link Date} value. Throws {@link SQLException} if the
+   * string is not a valid {@link Date} value.
+   */
+  static Date parseDate(String val) throws SQLException {
+    Preconditions.checkNotNull(val);
+    try {
+      return JdbcTypeConverter.toSqlDate(com.google.cloud.Date.parseDate(val));
+    } catch (IllegalArgumentException e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid date", val), com.google.rpc.Code.INVALID_ARGUMENT, e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a {@link Date} value in the timezone of the given {@link
+   * Calendar}. Throws {@link SQLException} if the string is not a valid {@link Date} value.
+   */
+  static Date parseDate(String val, Calendar cal) throws SQLException {
+    Preconditions.checkNotNull(val);
+    Preconditions.checkNotNull(cal);
+    try {
+      return JdbcTypeConverter.toSqlDate(com.google.cloud.Date.parseDate(val), cal);
+    } catch (IllegalArgumentException e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid date", val), com.google.rpc.Code.INVALID_ARGUMENT, e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a {@link Time} value. Throws {@link SQLException} if the
+   * string is not a valid {@link Time} value.
+   */
+  static Time parseTime(String val) throws SQLException {
+    Preconditions.checkNotNull(val);
+    try {
+      return Time.valueOf(val);
+    } catch (IllegalArgumentException e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid time", val), com.google.rpc.Code.INVALID_ARGUMENT, e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a {@link Time} value in the timezone of the given {@link
+   * Calendar}. Throws {@link SQLException} if the string is not a valid {@link Time} value.
+   */
+  static Time parseTime(String val, Calendar cal) throws SQLException {
+    Preconditions.checkNotNull(val);
+    Preconditions.checkNotNull(cal);
+    try {
+      return JdbcTypeConverter.parseSqlTime(val, cal);
+    } catch (IllegalArgumentException e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid time", val), com.google.rpc.Code.INVALID_ARGUMENT, e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a {@link Timestamp} value. Throws {@link SQLException} if the
+   * string is not a valid {@link Timestamp} value.
+   */
+  static Timestamp parseTimestamp(String val) throws SQLException {
+    Preconditions.checkNotNull(val);
+    try {
+      return JdbcTypeConverter.toSqlTimestamp(com.google.cloud.Timestamp.parseTimestamp(val));
+    } catch (Exception e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid timestamp", val),
+          com.google.rpc.Code.INVALID_ARGUMENT,
+          e);
+    }
+  }
+
+  /**
+   * Parses the given string value as a {@link Timestamp} value in the timezone of the given {@link
+   * Calendar}. Throws {@link SQLException} if the string is not a valid {@link Timestamp} value.
+   */
+  static Timestamp parseTimestamp(String val, Calendar cal) throws SQLException {
+    Preconditions.checkNotNull(val);
+    Preconditions.checkNotNull(cal);
+    try {
+      return JdbcTypeConverter.setTimestampInCalendar(
+          com.google.cloud.Timestamp.parseTimestamp(val).toSqlTimestamp(), cal);
+    } catch (Exception e) {
+      throw JdbcSqlExceptionFactory.of(
+          String.format("%s is not a valid timestamp", val),
+          com.google.rpc.Code.INVALID_ARGUMENT,
+          e);
+    }
+  }
+
   /** Should return true if this object has been closed */
   public abstract boolean isClosed() throws SQLException;