SQOOP-584 Create facility to validate user supplied connection and job forms

git-svn-id: https://svn.apache.org/repos/asf/sqoop/branches/sqoop2@1377757 13f79535-47bb-0310-9956-ffa450edef68

common/src/main/java/org/apache/sqoop/model/MForm.java

@@ -24,7 +24,7 @@
  * input gathering process to be broken down into multiple steps that can be
  * then paged through by the user interface.
  */
-public final class MForm extends MNamedElement {
+public final class MForm extends MValidatedElement {
 
   private final List<MInput<?>> inputs;
 

common/src/main/java/org/apache/sqoop/model/MInput.java

@@ -22,7 +22,7 @@
  * or a job object.
  * @param <T> the value type associated with this parameter
  */
-public abstract class MInput<T> extends MNamedElement {
+public abstract class MInput<T> extends MValidatedElement {
   private T value;
 
   protected MInput(String name) {

common/src/main/java/org/apache/sqoop/model/MNamedElement.java

@@ -28,8 +28,6 @@ public abstract class MNamedElement extends MPersistableEntity {
   private final String labelKey;
   private final String helpKey;
 
-  private String errorMessage;
-
   protected MNamedElement(String name) {
     this.name = name;
 
@@ -58,19 +56,5 @@ public String getHelpKey() {
     return helpKey;
   }
 
-  /**
-   * @param errMsg any error message associated with this parameter
-   */
-  public void setErrorMessage(String errMsg) {
-    this.errorMessage = errMsg;
-  }
-
-  /**
-   * @return any error message associated with this parameter
-   */
-  public String getErrorMessage() {
-    return this.errorMessage;
-  }
-
   public abstract String toString();
 }

common/src/main/java/org/apache/sqoop/model/MValidatedElement.java

@@ -0,0 +1,150 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sqoop.model;
+
+/**
+ * Element that can be validated for correctness.
+ *
+ * Two severity levels are supported at the moment - warning and error.
+ *
+ * Warning:
+ * Warning is something suspicious, potentially wrong but something that
+ * can be ignored. For example in case of JDBC URL element, warning would
+ * be if specified host is not responding - it's warning because specified
+ * URL might be wrong. However at the same time URL might be right as only
+ * target host might be down.
+ *
+ * Error:
+ * Error represents unacceptable element content. For example in case of JDBC
+ * URL path, error would be empty element or element containing invalid URL.
+ */
+abstract public class MValidatedElement extends MNamedElement {
+
+  /**
+   * Different levels of validation severity.
+   */
+  public enum Severity {
+    /**
+     * Everything is fine, no issues with this element.
+     */
+    OK,
+
+    /**
+     * Warning is suspicious content of the element.
+     */
+    WARNING,
+
+    /**
+     * Error is incorrect, unacceptable content of the element.
+     */
+    ERROR,
+  }
+
+  /**
+   * Validation message.
+   *
+   * One element can have only one message regardless of the type.
+   */
+  private String validationMessage;
+
+  /**
+   * Severity of the message.
+   */
+  private Severity validationSeverity;
+
+  public MValidatedElement(String name) {
+    super(name);
+    // Everything is fine by default
+    this.validationSeverity = Severity.OK;
+  }
+
+  /**
+   * Set validation message and given severity.
+   *
+   * @param severity Message severity
+   * @param msg Message itself
+   */
+  public void setValidationMessage(Severity severity, String msg) {
+    this.validationMessage = msg;
+    this.validationSeverity = severity;
+  }
+
+  /**
+   * Return validation message for given severity.
+   *
+   * Return either associated message for given severity or null in case
+   * that there is no message with given severity.
+   *
+   * @param severity Message severity
+   */
+  public String getValidationMessage(Severity severity) {
+    return (validationSeverity == severity) ? validationMessage : null;
+  }
+
+  /**
+   * Return validation message.
+   *
+   * Return current validation message.
+   */
+  public String getValidationMessage() {
+    return validationMessage;
+  }
+
+  /**
+   * Return message severity.
+   */
+  public Severity getValidationSeverity() {
+    return validationSeverity;
+  }
+
+  /**
+   * Set error message for this element.
+   *
+   * @param errMsg Error message
+   */
+  public void setErrorMessage(String errMsg) {
+    setValidationMessage(Severity.ERROR, errMsg);
+  }
+
+  /**
+   * Return error message associated with this element.
+   *
+   * @return Error message
+   */
+  public String getErrorMessage() {
+    return getValidationMessage(Severity.ERROR);
+  }
+
+  /**
+   * Set warning message for this element.
+   *
+   * @param warnMsg Warning message
+   */
+  public void setWarningMessage(String warnMsg) {
+    setValidationMessage(Severity.WARNING, warnMsg);
+  }
+
+  /**
+   * Retrieve warning message associated with this element.
+   * @return
+   */
+  public String getWarningMessage() {
+    return getValidationMessage(Severity.WARNING);
+  }
+
+}

connector/connector-generic-jdbc/src/main/java/org/apache/sqoop/connector/jdbc/GenericJdbcConnector.java

@@ -32,6 +32,8 @@
 import org.apache.sqoop.model.MMapInput;
 import org.apache.sqoop.model.MStringInput;
 import org.apache.sqoop.connector.spi.SqoopConnector;
+import org.apache.sqoop.validation.Validator;
+
 import static org.apache.sqoop.connector.jdbc.GenericJdbcConnectorConstants.*;
 
 
@@ -118,4 +120,9 @@ public Exporter getExporter() {
     return EXPORTER;
   }
 
+  @Override
+  public Validator getValidator() {
+    return new Validator();
+  }
+
 }

connector/connector-mysql-jdbc/src/main/java/org/apache/sqoop/connector/mysqljdbc/MySqlJdbcConnector.java

@@ -28,6 +28,7 @@
 import org.apache.sqoop.model.MForm;
 import org.apache.sqoop.connector.spi.SqoopConnector;
 import org.apache.sqoop.model.MJobForms;
+import org.apache.sqoop.validation.Validator;
 
 public class MySqlJdbcConnector implements SqoopConnector {
 
@@ -61,4 +62,9 @@ public Exporter getExporter() {
     // TODO Auto-generated method stub
     return null;
   }
+
+  @Override
+  public Validator getValidator() {
+    return new Validator();
+  }
 }

spi/src/main/java/org/apache/sqoop/connector/spi/SqoopConnector.java

@@ -25,6 +25,7 @@
 import org.apache.sqoop.job.etl.Importer;
 import org.apache.sqoop.model.MJobForms;
 import org.apache.sqoop.model.MConnectionForms;
+import org.apache.sqoop.validation.Validator;
 
 /**
  * Service provider interface for Sqoop Connectors.
@@ -57,4 +58,13 @@ public interface SqoopConnector {
    */
   public Exporter getExporter();
 
+  /**
+   * Returns validation object that Sqoop framework can use to validate user
+   * supplied forms before accepting them. This object will be used both for
+   * connection and job forms.
+   *
+   * @return Validator object
+   */
+  public Validator getValidator();
+
 }

spi/src/main/java/org/apache/sqoop/validation/Status.java

@@ -0,0 +1,45 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sqoop.validation;
+
+/**
+ * Status modes of a validation process.
+ */
+public enum Status {
+  /**
+   * Everything is correct.
+   *
+   * There are no issues, no warnings, nothing.
+   */
+  FINE,
+
+  /**
+   * Validated entity is correct enough to be processed.
+   *
+   * There might be some warnings, but no errors. It should be safe
+   * to proceed with processing.
+   */
+  ACCEPTABLE,
+
+  /**
+   * There are serious issues with validated entity.
+   *
+   * We can't proceed until reported issues will be resolved.
+   */
+  UNACCEPTABLE,
+}

spi/src/main/java/org/apache/sqoop/validation/Validator.java

@@ -0,0 +1,114 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sqoop.validation;
+
+import org.apache.sqoop.model.MConnectionForms;
+import org.apache.sqoop.model.MForm;
+import org.apache.sqoop.model.MJob;
+import org.apache.sqoop.model.MJobForms;
+
+import java.util.List;
+
+/**
+ * Connection and job metadata validator.
+ *
+ * This class should be extended by connector to provide form validation for
+ * connection and job forms. All methods are returning only validation Status.
+ * List of error and warning messages is directly updated in given structures.
+ * You can use methods getErrorMessage and getWarningMessage to retrieve them
+ * or setErrorMessage and setWarningMessage to set them.
+ *
+ * There are two major use cases of this class - simple and advanced. In simple
+ * mode connector developer should override method validate(MForm). This method
+ * will get exactly one form for validation at the time. All other methods in
+ * default implementation will eventually delegate call to this method. There
+ * is no implicit way how to distinguish between connection and job form or how
+ * to reference different forms.
+ *
+ * In advance usage user should override methods validate(MConnectionForms) and
+ * validate(MJobForms). Both methods will be called with all form gathered so far
+ * and connector developer might use information from all forms to do cross
+ * form validations.
+ */
+public class Validator {
+
+  /**
+   * Validate one single form.
+   *
+   * @param form Form to be validated
+   * @return Validation status
+   */
+  public Status validate(MForm form) {
+    return Status.FINE;
+  }
+
+  /**
+   * Internal method used to validate arbitrary list of forms.
+   *
+   * It's delegating validation to validate(MForm) method. Return
+   * status will be the highest defined in Status enumeration (e.g. the worst).
+   *
+   * @param forms List of forms to be validated
+   * @return Validation status
+   */
+  protected Status validate(List<MForm> forms) {
+    Status finalStatus = Status.FINE;
+    for (MForm form : forms) {
+      Status status = validate(form);
+
+      if ( finalStatus.compareTo(status) > 0 ) {
+        finalStatus = status;
+      }
+    }
+
+    return finalStatus;
+  }
+
+  /**
+   * Validate connection forms.
+   *
+   * This method will be called when user will try to create new connection
+   * in the system. It must return FINE or ACCEPTABLE in order to proceed and
+   * save the job in metadata repository.
+   *
+   * Default implementation will delegate the task to validate(MForm).
+   *
+   * @param connection Connection to be validated
+   * @return Validation status
+   */
+  public Status validate(MConnectionForms connection) {
+    return validate(connection.getForms());
+  }
+
+  /**
+   * Validate job forms.
+   *
+   * This method will be called when user will try to create new job in the
+   * system. It must return FINE or ACCEPTABLE in order to proceed and save
+   * the job in metadata repository.
+   *
+   * Default implementation will delegate the job to validate(MForm).
+   *
+   * @param job Job to be validated
+   * @return Validation status
+   */
+  public Status validate(MJobForms job) {
+    return validate(job.getForms());
+  }
+
+}