MultiplePsiJavaStubDataSource.java

package jetbrains.mps.idea.java.psiStubs;

/*Generated by MPS */

import jetbrains.mps.extapi.persistence.DataSourceBase;
import java.util.List;
import org.jetbrains.mps.openapi.persistence.DataSourceListener;
import jetbrains.mps.internal.collections.runtime.ListSequence;
import java.util.ArrayList;
import com.intellij.openapi.module.Module;
import com.intellij.psi.PsiDirectory;
import jetbrains.mps.internal.collections.runtime.Sequence;
import jetbrains.mps.internal.collections.runtime.ISelector;
import com.intellij.psi.PsiJavaFile;
import jetbrains.mps.internal.collections.runtime.ITranslator2;
import org.jetbrains.mps.openapi.persistence.DataSource;
import jetbrains.mps.internal.collections.runtime.IVisitor;

/**
 * Data source for a number of psi directories.
 * It accumulates events from many psi java stub data sources.
 */
public class MultiplePsiJavaStubDataSource extends DataSourceBase implements JavaFilesHolder, PsiJavaStubListener {
  private final Object LOCK = new Object();
  private List<PsiJavaStubDataSource> myDataSources;
  private List<DataSourceListener> myListeners = ListSequence.fromList(new ArrayList<DataSourceListener>());

  public MultiplePsiJavaStubDataSource(final Module module, Iterable<PsiDirectory> dirs) {
    myDataSources = Sequence.fromIterable(dirs).select(new ISelector<PsiDirectory, PsiJavaStubDataSource>() {
      public PsiJavaStubDataSource select(PsiDirectory it) {
        return new PsiJavaStubDataSource(module, it);
      }
    }).toListSequence();
  }

  public Iterable<PsiJavaFile> getJavaFiles() {
    return ListSequence.fromList(myDataSources).translate(new ITranslator2<PsiJavaStubDataSource, PsiJavaFile>() {
      public Iterable<PsiJavaFile> translate(PsiJavaStubDataSource it) {
        return it.getJavaFiles();
      }
    });
  }

  public void changed(final DataSource source, final PsiJavaStubEvent event) {
    synchronized (LOCK) {
      ListSequence.fromList(myListeners).visitAll(new IVisitor<DataSourceListener>() {
        public void visit(DataSourceListener it) {
          if (it instanceof PsiJavaStubListener) {
            ((PsiJavaStubListener) it).changed(source, event);
          } else {
            it.changed(source);
          }
        }
      });
    }
  }
  public void changed(final DataSource source) {
    synchronized (LOCK) {
      // Q: pass this dataSource 'this' or original 'source' ? 
      ListSequence.fromList(myListeners).visitAll(new IVisitor<DataSourceListener>() {
        public void visit(DataSourceListener it) {
          it.changed(source);
        }
      });
    }
  }

  @Override
  public void addListener(DataSourceListener listener) {
    super.addListener(listener);
    synchronized (LOCK) {
      if (ListSequence.fromList(myListeners).isEmpty()) {
        startListening();
      }
      ListSequence.fromList(myListeners).addElement(listener);
    }
  }

  @Override
  public void removeListener(DataSourceListener listener) {
    synchronized (LOCK) {
      ListSequence.fromList(myListeners).removeElement(listener);
      if (ListSequence.fromList(myListeners).isEmpty()) {
        stopListening();
      }
    }
  }

  private void startListening() {
    ListSequence.fromList(myDataSources).visitAll(new IVisitor<PsiJavaStubDataSource>() {
      public void visit(PsiJavaStubDataSource it) {
        it.addListener(MultiplePsiJavaStubDataSource.this);
      }
    });
  }

  private void stopListening() {
    ListSequence.fromList(myDataSources).visitAll(new IVisitor<PsiJavaStubDataSource>() {
      public void visit(PsiJavaStubDataSource it) {
        it.removeListener(MultiplePsiJavaStubDataSource.this);
      }
    });
  }
}