dart/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/text/dart/CompletionProposalCategory.java

/*
 * Copyright (c) 2012, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (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.eclipse.org/legal/epl-v10.html
 * 
 * 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 com.google.dart.tools.ui.internal.text.dart;

import com.google.dart.engine.utilities.instrumentation.Instrumentation;
import com.google.dart.engine.utilities.instrumentation.InstrumentationBuilder;
import com.google.dart.tools.ui.DartToolsPlugin;
import com.google.dart.tools.ui.Messages;
import com.google.dart.tools.ui.text.dart.ContentAssistInvocationContext;

import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.InvalidRegistryObjectException;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.jface.action.LegacyActionTools;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.osgi.framework.Bundle;

import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Describes a category extension to the "javaCompletionProposalComputer" extension point.
 */
@SuppressWarnings({"rawtypes", "unchecked"})
public final class CompletionProposalCategory {
  /** The extension schema name of the icon attribute. */
  private static final String ICON = "icon"; //$NON-NLS-1$

  private final String fId;
  private final String fName;
  private final IConfigurationElement fElement;
  /**
   * The image descriptor for this category, or <code>null</code> if none specified.
   */
  private final ImageDescriptor fImage;

  private boolean fIsSeparateCommand = true;
  private boolean fIsEnabled = true;
  private boolean fIsIncluded = true;
  private final CompletionProposalComputerRegistry fRegistry;

  private int fSortOrder = 0x10000;
  private String fLastError = null;

  CompletionProposalCategory(IConfigurationElement element,
      CompletionProposalComputerRegistry registry) {
    fElement = element;
    fRegistry = registry;
    IExtension parent = (IExtension) element.getParent();
    fId = parent.getUniqueIdentifier();
    checkNotNull(fId, "id"); //$NON-NLS-1$
    String name = parent.getLabel();
    if (name == null) {
      fName = fId;
    } else {
      fName = name;
    }

    String icon = element.getAttribute(ICON);
    ImageDescriptor img = null;
    if (icon != null) {
      Bundle bundle = getBundle();
      if (bundle != null) {
        Path path = new Path(icon);
        URL url = FileLocator.find(bundle, path, null);
        img = ImageDescriptor.createFromURL(url);
      }
    }
    fImage = img;

  }

  CompletionProposalCategory(String id, String name, CompletionProposalComputerRegistry registry) {
    fRegistry = registry;
    fId = id;
    fName = name;
    fElement = null;
    fImage = null;
  }

  /**
   * Safely computes completion proposals of all computers of this category through their extension.
   * If an extension is disabled, throws an exception or otherwise does not adhere to the contract
   * described in {@link com.google.dart.tools.ui.text.dart.IDartCompletionProposalComputer}, it is
   * disabled.
   * 
   * @param context the invocation context passed on to the extension
   * @param partition the partition type where to invocation occurred
   * @param monitor the progress monitor passed on to the extension
   * @return the list of computed completion proposals (element type:
   *         {@link org.eclipse.jface.text.contentassist.ICompletionProposal})
   */
  public List<ICompletionProposal> computeCompletionProposals(
      ContentAssistInvocationContext context, String partition, SubProgressMonitor monitor) {

    InstrumentationBuilder instrumentation = Instrumentation.builder("CompletionProposals");

    try {

      fLastError = null;
      List<ICompletionProposal> result = new ArrayList<ICompletionProposal>();
      List descriptors = new ArrayList(fRegistry.getProposalComputerDescriptors(partition));
      for (Iterator it = descriptors.iterator(); it.hasNext();) {
        CompletionProposalComputerDescriptor desc = (CompletionProposalComputerDescriptor) it.next();
        if (desc.getCategory() == this) {
          result.addAll(desc.computeCompletionProposals(context, monitor));
        }
        if (fLastError == null) {
          fLastError = desc.getErrorMessage();
        }
      }
      instrumentation.metric("Results-Count", result.size());
      return result;
    } finally {
      instrumentation.log();
    }
  }

  /**
   * Safely computes context information objects of all computers of this category through their
   * extension. If an extension is disabled, throws an exception or otherwise does not adhere to the
   * contract described in
   * {@link com.google.dart.tools.ui.text.dart.IDartCompletionProposalComputer}, it is disabled.
   * 
   * @param context the invocation context passed on to the extension
   * @param partition the partition type where to invocation occurred
   * @param monitor the progress monitor passed on to the extension
   * @return the list of computed context information objects (element type:
   *         {@link org.eclipse.jface.text.contentassist.IContextInformation})
   */
  public List<IContextInformation> computeContextInformation(
      ContentAssistInvocationContext context, String partition, SubProgressMonitor monitor) {
    fLastError = null;
    List<IContextInformation> result = new ArrayList<IContextInformation>();
    List descriptors = new ArrayList(fRegistry.getProposalComputerDescriptors(partition));
    for (Iterator it = descriptors.iterator(); it.hasNext();) {
      CompletionProposalComputerDescriptor desc = (CompletionProposalComputerDescriptor) it.next();
      if (desc.getCategory() == this) {
        result.addAll(desc.computeContextInformation(context, monitor));
      }
      if (fLastError == null) {
        fLastError = desc.getErrorMessage();
      }
    }
    return result;
  }

  /**
   * Returns the name of the described extension without mnemonic hint in order to be displayed in a
   * message.
   * 
   * @return Returns the name
   */
  public String getDisplayName() {
    return LegacyActionTools.removeMnemonics(fName);
  }

  /**
   * Returns the error message from the computers in this category.
   * 
   * @return the error message from the computers in this category
   */
  public String getErrorMessage() {
    return fLastError;
  }

  /**
   * Returns the identifier of the described extension.
   * 
   * @return Returns the id
   */
  public String getId() {
    return fId;
  }

  /**
   * Returns the image descriptor of the described category.
   * 
   * @return the image descriptor of the described category
   */
  public ImageDescriptor getImageDescriptor() {
    return fImage;
  }

  /**
   * Returns the name of the described extension.
   * 
   * @return Returns the name
   */
  public String getName() {
    return fName;
  }

  /**
   * @return sortOrder
   */
  public int getSortOrder() {
    return fSortOrder;
  }

  /**
   * Returns <code>true</code> if the category contains any computers, <code>false</code> otherwise.
   * 
   * @return <code>true</code> if the category contains any computers, <code>false</code> otherwise
   */
  public boolean hasComputers() {
    List descriptors = fRegistry.getProposalComputerDescriptors();
    for (Iterator it = descriptors.iterator(); it.hasNext();) {
      CompletionProposalComputerDescriptor desc = (CompletionProposalComputerDescriptor) it.next();
      if (desc.getCategory() == this) {
        return true;
      }
    }
    return false;
  }

  /**
   * Returns <code>true</code> if the category contains any computers in the given partition,
   * <code>false</code> otherwise.
   * 
   * @param partition the partition
   * @return <code>true</code> if the category contains any computers, <code>false</code> otherwise
   */
  public boolean hasComputers(String partition) {
    List descriptors = fRegistry.getProposalComputerDescriptors(partition);
    for (Iterator it = descriptors.iterator(); it.hasNext();) {
      CompletionProposalComputerDescriptor desc = (CompletionProposalComputerDescriptor) it.next();
      if (desc.getCategory() == this) {
        return true;
      }
    }
    return false;
  }

  public boolean isEnabled() {
    return fIsEnabled;
  }

  /**
   * @return included
   */
  public boolean isIncluded() {
    return fIsIncluded;
  }

  /**
   * Returns the enablement state of the category.
   * 
   * @return the enablement state of the category
   */
  public boolean isSeparateCommand() {
    return fIsSeparateCommand;
  }

  /**
   * Notifies the computers in this category of a proposal computation session end.
   */
  public void sessionEnded() {
    List descriptors = new ArrayList(fRegistry.getProposalComputerDescriptors());
    for (Iterator it = descriptors.iterator(); it.hasNext();) {
      CompletionProposalComputerDescriptor desc = (CompletionProposalComputerDescriptor) it.next();
      if (desc.getCategory() == this) {
        desc.sessionEnded();
      }
      if (fLastError == null) {
        fLastError = desc.getErrorMessage();
      }
    }
  }

  /**
   * Notifies the computers in this category of a proposal computation session start.
   */
  public void sessionStarted() {
    List descriptors = new ArrayList(fRegistry.getProposalComputerDescriptors());
    for (Iterator it = descriptors.iterator(); it.hasNext();) {
      CompletionProposalComputerDescriptor desc = (CompletionProposalComputerDescriptor) it.next();
      if (desc.getCategory() == this) {
        desc.sessionStarted();
      }
      if (fLastError == null) {
        fLastError = desc.getErrorMessage();
      }
    }
  }

  public void setEnabled(boolean isEnabled) {
    fIsEnabled = isEnabled;
  }

  /**
   * @param included the included
   */
  public void setIncluded(boolean included) {
    fIsIncluded = included;
  }

  /**
   * Sets the separate command state of the category.
   * 
   * @param enabled the new enabled state.
   */
  public void setSeparateCommand(boolean enabled) {
    fIsSeparateCommand = enabled;
  }

  /**
   * @param sortOrder the sortOrder
   */
  public void setSortOrder(int sortOrder) {
    fSortOrder = sortOrder;
  }

  /**
   * Checks an element that must be defined according to the extension point schema. Throws an
   * <code>InvalidRegistryObjectException</code> if <code>obj</code> is <code>null</code>.
   */
  private void checkNotNull(Object obj, String attribute) throws InvalidRegistryObjectException {
    if (obj == null) {
      Object[] args = {getId(), fElement.getContributor().getName(), attribute};
      String message = Messages.format(
          DartTextMessages.CompletionProposalComputerDescriptor_illegal_attribute_message,
          args);
      IStatus status = new Status(
          IStatus.WARNING,
          DartToolsPlugin.getPluginId(),
          IStatus.OK,
          message,
          null);
      DartToolsPlugin.log(status);
      throw new InvalidRegistryObjectException();
    }
  }

  private Bundle getBundle() {
    String namespace = fElement.getDeclaringExtension().getContributor().getName();
    Bundle bundle = Platform.getBundle(namespace);
    return bundle;
  }

}