Merged BuildContext2 back into BuildContext

Introduced convenience hasDelta(File) method
Introduced new isUpdate(File target, File source) method

git-svn-id: file:///opt/svn/repositories/sonatype.org/spice/trunk/plexus-build-api@1829 5751e0cb-dcb7-432f-92e2-260806df54be

Author: Igor Fedorenko

src/main/java/org/sonatype/plexus/build/incremental/BuildContext.java

@@ -33,6 +33,14 @@ public interface BuildContext {
    */
   boolean hasDelta(String relpath);
 
+  /**
+   * Returns <code>true</code> if the file has changed since last build or is not
+   * under basedir.
+   * 
+   * @since 0.5.0
+   */
+  boolean hasDelta(File file);
+
   /**
    * Returns <code>true</code> if any file or folder identified by <code>relpaths</code> has 
    * changed since last build.
@@ -82,7 +90,17 @@ public interface BuildContext {
    * If <code>ignoreDelta</code> is <code>true</code>, the scanner will "see" all
    * files and folders. 
    * 
+   * Please beware that ignoreDelta=false does NOT work reliably for operations
+   * that copy resources from source to target locations. Returned Scanner
+   * only scans changed source resources and it does not consider changed or deleted
+   * target resources. This results in missing or stale target resources.
+   * Starting with 0.5.0, recommended way to process resources is to use
+   * #newScanner(basedir,true) to locate all source resources and {@link #isUptodate(File, File)}
+   * to optimized processing of uptodate target resources. 
+   * 
    * Returns empty Scanner if <code>basedir</code> is not under this build context basedir.
+   * 
+   * @see http://jira.codehaus.org/browse/MSHARED-125
    */
   Scanner newScanner(File basedir, boolean ignoreDelta);
 
@@ -111,7 +129,7 @@ public interface BuildContext {
    *
    * @see #getValue(String)
    */
-  public void setValue(String key, Object value);
+  void setValue(String key, Object value);
 
   /**
    * Returns value associated with <code>key</code> during previous mojo execution.
@@ -123,6 +141,29 @@ public interface BuildContext {
    * @see #setValue(String, Object)
    * @see #isIncremental()
    */
-  public Object getValue(String key);
+  Object getValue(String key);
+
+  /**
+   * 
+   * @since 0.5.0
+   */
+  void addWarning(File file, int line, int column, String message, Throwable cause);
+
+  /**
+   * 
+   * @since 0.5.0
+   */
+  void addError(File file, int line, int column, String message, Throwable cause);
+
+  /**
+   * Returns true, if the target file exists and is uptodate compared to the source file.
+   * 
+   * More specifically, this method returns true when both target and source files exist,
+   * do not have changes since last incremental build and the target file was last modified
+   * later than the source file. Returns false in all other cases.
+   * 
+   * @since 0.5.0
+   */
+  boolean isUptodate(File target, File source);
 
 }

src/main/java/org/sonatype/plexus/build/incremental/BuildContext2.java

@@ -27,7 +27,7 @@
  * were just created. More specifically, 
  * 
  * hasDelta returns <code>true</code> for all paths
- * newScanner returns Scanner that scanns all files under provided basedir
+ * newScanner returns Scanner that scans all files under provided basedir
  * newDeletedScanner always returns empty scanner.
  * isIncremental returns <code>false</code<
  * getValue always returns <code>null</code>
@@ -41,6 +41,10 @@ public boolean hasDelta(String relpath) {
     return true;
   }
 
+  public boolean hasDelta(File file) {
+    return true;
+  }
+
   public boolean hasDelta(List relpaths) {
     return true;
   }
@@ -83,4 +87,9 @@ public void addWarning(File file, int line, int column, String message, Throwabl
 
   public void addError(File file, int line, int column, String message, Throwable cause) {
   }
+
+  public boolean isUptodate(File target, File source) {
+    return target != null && target.exists() && source != null && source.exists()
+        && target.lastModified() > source.lastModified();
+  }
 }

src/main/java/org/sonatype/plexus/build/incremental/DefaultBuildContext.java

@@ -29,7 +29,7 @@
  * Apparently, older version of plexus used by maven-filtering and likely
  * other projects, does not honour "default" role-hint.
  */
-public class ThreadBuildContext implements BuildContext, BuildContext2 {
+public class ThreadBuildContext implements BuildContext {
 
   private static final ThreadLocal threadContext = new ThreadLocal();
 
@@ -51,6 +51,10 @@ public boolean hasDelta(String relPath) {
     return getContext().hasDelta(relPath);
   }
 
+  public boolean hasDelta(File file) {
+    return getContext().hasDelta(file);
+  }
+
   public boolean hasDelta(List relPaths) {
     return getContext().hasDelta(relPaths);
   }
@@ -88,17 +92,14 @@ public void setValue(String key, Object value) {
   }
 
   public void addWarning(File file, int line, int column, String message, Throwable cause) {
-    BuildContext context = getContext();
-    if (context instanceof BuildContext2) {
-	  ((BuildContext2) context).addWarning(file, line, column, message, cause);
-    }
+    getContext().addWarning(file, line, column, message, cause);
   }
 
   public void addError(File file, int line, int column, String message, Throwable cause) {
-    BuildContext context = getContext();
-    if (context instanceof BuildContext2) {
-      ((BuildContext2) context).addError(file, line, column, message, cause);
-    }
+    getContext().addError(file, line, column, message, cause);
   }
 
+  public boolean isUptodate(File target, File source) {
+    return getContext().isUptodate(target, source);
+  }
 }