Add type parameter for Command interface

Strong typing of Command's response type
This closes #1272

Author: kwin

maven-scm-api/src/main/java/org/apache/maven/scm/command/AbstractCommand.java

@@ -29,16 +29,17 @@
 /**
  * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
+ * @param <T>
  *
  */
-public abstract class AbstractCommand implements Command {
+public abstract class AbstractCommand<T extends ScmResult> implements Command<T> {
     protected Logger logger = LoggerFactory.getLogger(getClass());
 
-    protected abstract ScmResult executeCommand(
+    protected abstract T executeCommand(
             ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException;
 
     /** {@inheritDoc} */
-    public final ScmResult execute(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
+    public final T execute(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
             throws ScmException {
         if (repository == null) {
             throw new NullPointerException("repository cannot be null");

maven-scm-api/src/main/java/org/apache/maven/scm/command/Command.java

@@ -27,9 +27,9 @@
 /**
  * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
- *
+ * @param <T> the type of result returned by this command
  */
-public interface Command {
+public interface Command<T extends ScmResult> {
     /** Plexus component key */
     String ROLE = Command.class.getName();
 
@@ -40,6 +40,5 @@ public interface Command {
      * @return the result object
      * @throws ScmException if any
      */
-    ScmResult execute(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException;
+    T execute(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException;
 }

maven-scm-api/src/main/java/org/apache/maven/scm/command/add/AbstractAddCommand.java

@@ -22,20 +22,19 @@
 import org.apache.maven.scm.CommandParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
 
 /**
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
  *
  */
-public abstract class AbstractAddCommand extends AbstractCommand {
-    protected abstract ScmResult executeAddCommand(
+public abstract class AbstractAddCommand extends AbstractCommand<AddScmResult> {
+    protected abstract AddScmResult executeAddCommand(
             ScmProviderRepository repository, ScmFileSet fileSet, String message, boolean binary) throws ScmException;
 
     /** {@inheritDoc} */
-    protected ScmResult executeCommand(
+    protected AddScmResult executeCommand(
             ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         return executeAddCommand(
                 repository,

maven-scm-api/src/main/java/org/apache/maven/scm/command/blame/AbstractBlameCommand.java

@@ -22,19 +22,18 @@
 import org.apache.maven.scm.CommandParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
 
 /**
  * @author Evgeny Mandrikov
  * @since 1.4
  */
-public abstract class AbstractBlameCommand extends AbstractCommand {
+public abstract class AbstractBlameCommand extends AbstractCommand<BlameScmResult> {
     public abstract BlameScmResult executeBlameCommand(
             ScmProviderRepository repo, ScmFileSet workingDirectory, String filename) throws ScmException;
 
-    protected ScmResult executeCommand(
+    protected BlameScmResult executeCommand(
             ScmProviderRepository repository, ScmFileSet workingDirectory, CommandParameters parameters)
             throws ScmException {
         String file = parameters.getString(CommandParameter.FILE);

maven-scm-api/src/main/java/org/apache/maven/scm/command/branch/AbstractBranchCommand.java

@@ -24,7 +24,6 @@
 import org.apache.maven.scm.ScmBranchParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
 
@@ -33,8 +32,8 @@
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
  *
  */
-public abstract class AbstractBranchCommand extends AbstractCommand {
-    protected abstract ScmResult executeBranchCommand(
+public abstract class AbstractBranchCommand extends AbstractCommand<BranchScmResult> {
+    protected abstract BranchScmResult executeBranchCommand(
             ScmProviderRepository repository, ScmFileSet fileSet, String branchName, String message)
             throws ScmException;
 
@@ -48,7 +47,7 @@ protected abstract ScmResult executeBranchCommand(
      * @return TODO
      * @throws ScmException if any
      */
-    protected ScmResult executeBranchCommand(
+    protected BranchScmResult executeBranchCommand(
             ScmProviderRepository repository,
             ScmFileSet fileSet,
             String branchName,
@@ -58,8 +57,8 @@ protected ScmResult executeBranchCommand(
     }
 
     /** {@inheritDoc} */
-    public ScmResult executeCommand(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException {
+    public BranchScmResult executeCommand(
+            ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         String branchName = parameters.getString(CommandParameter.BRANCH_NAME);
 
         ScmBranchParameters scmBranchParameters =

maven-scm-api/src/main/java/org/apache/maven/scm/command/changelog/AbstractChangeLogCommand.java

@@ -25,7 +25,6 @@
 import org.apache.maven.scm.ScmBranch;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.ScmVersion;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
@@ -35,7 +34,7 @@
  * @author Olivier Lamy
  *
  */
-public abstract class AbstractChangeLogCommand extends AbstractCommand implements ChangeLogCommand {
+public abstract class AbstractChangeLogCommand extends AbstractCommand<ChangeLogScmResult> implements ChangeLogCommand {
     @Deprecated
     protected abstract ChangeLogScmResult executeChangeLogCommand(
             ScmProviderRepository repository,
@@ -67,8 +66,8 @@ protected ChangeLogScmResult executeChangeLogCommand(
     /**
      * {@inheritDoc}
      */
-    public ScmResult executeCommand(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException {
+    public ChangeLogScmResult executeCommand(
+            ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         Date startDate = parameters.getDate(CommandParameter.START_DATE, null);
 
         Date endDate = parameters.getDate(CommandParameter.END_DATE, null);

maven-scm-api/src/main/java/org/apache/maven/scm/command/checkin/AbstractCheckInCommand.java

@@ -22,7 +22,6 @@
 import org.apache.maven.scm.CommandParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.ScmVersion;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
@@ -33,15 +32,15 @@
  * @author Olivier Lamy
  *
  */
-public abstract class AbstractCheckInCommand extends AbstractCommand {
+public abstract class AbstractCheckInCommand extends AbstractCommand<CheckInScmResult> {
     public static final String NAME = "check-in";
 
     protected abstract CheckInScmResult executeCheckInCommand(
             ScmProviderRepository repository, ScmFileSet fileSet, String message, ScmVersion scmVersion)
             throws ScmException;
 
-    public ScmResult executeCommand(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException {
+    public CheckInScmResult executeCommand(
+            ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         String message = parameters.getString(CommandParameter.MESSAGE);
 
         ScmVersion scmVersion = parameters.getScmVersion(CommandParameter.SCM_VERSION, null);

maven-scm-api/src/main/java/org/apache/maven/scm/command/checkout/AbstractCheckOutCommand.java

@@ -22,7 +22,6 @@
 import org.apache.maven.scm.CommandParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.ScmVersion;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
@@ -33,7 +32,7 @@
  * @author Olivier Lamy
  *
  */
-public abstract class AbstractCheckOutCommand extends AbstractCommand {
+public abstract class AbstractCheckOutCommand extends AbstractCommand<CheckOutScmResult> {
     /**
      * Execute Check out command line in a recursive check out way.
      *
@@ -70,8 +69,8 @@ protected abstract CheckOutScmResult executeCheckOutCommand(
             throws ScmException;
 
     /** {@inheritDoc} */
-    public ScmResult executeCommand(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException {
+    public CheckOutScmResult executeCommand(
+            ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         ScmVersion scmVersion = parameters.getScmVersion(CommandParameter.SCM_VERSION, null);
         boolean recursive = parameters.getBoolean(CommandParameter.RECURSIVE, true);
         boolean shallow = parameters.getBoolean(CommandParameter.SHALLOW, false);

maven-scm-api/src/main/java/org/apache/maven/scm/command/diff/AbstractDiffCommand.java

@@ -22,7 +22,6 @@
 import org.apache.maven.scm.CommandParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.ScmVersion;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
@@ -37,14 +36,14 @@
  * @author <a href="mailto:brett@apache.org">Brett Porter</a>
  *
  */
-public abstract class AbstractDiffCommand extends AbstractCommand {
+public abstract class AbstractDiffCommand extends AbstractCommand<DiffScmResult> {
     protected abstract DiffScmResult executeDiffCommand(
             ScmProviderRepository repository, ScmFileSet fileSet, ScmVersion startRevision, ScmVersion endRevision)
             throws ScmException;
 
     /** {@inheritDoc} */
-    public ScmResult executeCommand(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException {
+    public DiffScmResult executeCommand(
+            ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         ScmVersion startRevision = parameters.getScmVersion(CommandParameter.START_SCM_VERSION, null);
 
         ScmVersion endRevision = parameters.getScmVersion(CommandParameter.END_SCM_VERSION, null);

maven-scm-api/src/main/java/org/apache/maven/scm/command/edit/AbstractEditCommand.java

@@ -21,20 +21,19 @@
 import org.apache.maven.scm.CommandParameters;
 import org.apache.maven.scm.ScmException;
 import org.apache.maven.scm.ScmFileSet;
-import org.apache.maven.scm.ScmResult;
 import org.apache.maven.scm.command.AbstractCommand;
 import org.apache.maven.scm.provider.ScmProviderRepository;
 
 /**
  *
  */
-public abstract class AbstractEditCommand extends AbstractCommand {
+public abstract class AbstractEditCommand extends AbstractCommand<EditScmResult> {
     /** {@inheritDoc} */
-    public ScmResult executeCommand(ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters)
-            throws ScmException {
+    public EditScmResult executeCommand(
+            ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
         return executeEditCommand(repository, fileSet);
     }
 
-    protected abstract ScmResult executeEditCommand(ScmProviderRepository repository, ScmFileSet fileSet)
+    protected abstract EditScmResult executeEditCommand(ScmProviderRepository repository, ScmFileSet fileSet)
             throws ScmException;
 }