JavaEditorTextHoverDescriptor.java :  » IDE-Eclipse » jdt » org » eclipse » jdt » internal » ui » text » java » hover » Java Open Source

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.internal.ui.text.java.hover;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.StringTokenizer;

import org.osgi.framework.Bundle;

import org.eclipse.swt.SWT;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;

import org.eclipse.jdt.ui.PreferenceConstants;
import org.eclipse.jdt.ui.text.java.hover.IJavaEditorTextHover;

import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.javaeditor.EditorUtility;

/**
 * Describes a Java editor text hover.
 *
 * @since 2.1
 */
public class JavaEditorTextHoverDescriptor {

  private static final String JAVA_EDITOR_TEXT_HOVER_EXTENSION_POINT= "org.eclipse.jdt.ui.javaEditorTextHovers"; //$NON-NLS-1$
  private static final String HOVER_TAG= "hover"; //$NON-NLS-1$
  private static final String ID_ATTRIBUTE= "id"; //$NON-NLS-1$
  private static final String CLASS_ATTRIBUTE= "class"; //$NON-NLS-1$
  private static final String LABEL_ATTRIBUTE= "label"; //$NON-NLS-1$
  private static final String ACTIVATE_PLUG_IN_ATTRIBUTE= "activate"; //$NON-NLS-1$
  private static final String DESCRIPTION_ATTRIBUTE= "description"; //$NON-NLS-1$

  public static final String NO_MODIFIER= "0"; //$NON-NLS-1$
  public static final String DISABLED_TAG= "!"; //$NON-NLS-1$
  public static final String VALUE_SEPARATOR= ";"; //$NON-NLS-1$

  private int fStateMask;
  private String fModifierString;
  private boolean fIsEnabled;

  private IConfigurationElement fElement;


  /**
   * Returns all Java editor text hovers contributed to the workbench.
   *
   * @return an array with the contributed text hovers
   */
  public static JavaEditorTextHoverDescriptor[] getContributedHovers() {
    IExtensionRegistry registry= Platform.getExtensionRegistry();
    IConfigurationElement[] elements= registry.getConfigurationElementsFor(JAVA_EDITOR_TEXT_HOVER_EXTENSION_POINT);
    JavaEditorTextHoverDescriptor[] hoverDescs= createDescriptors(elements);
    initializeFromPreferences(hoverDescs);
    return hoverDescs;
  }

  /**
   * Computes the state mask for the given modifier string.
   *
   * @param modifiers  the string with the modifiers, separated by '+', '-', ';', ',' or '.'
   * @return the state mask or -1 if the input is invalid
   */
  public static int computeStateMask(String modifiers) {
    if (modifiers == null)
      return -1;

    if (modifiers.length() == 0)
      return SWT.NONE;

    int stateMask= 0;
    StringTokenizer modifierTokenizer= new StringTokenizer(modifiers, ",;.:+-* "); //$NON-NLS-1$
    while (modifierTokenizer.hasMoreTokens()) {
      int modifier= EditorUtility.findLocalizedModifier(modifierTokenizer.nextToken());
      if (modifier == 0 || (stateMask & modifier) == modifier)
        return -1;
      stateMask= stateMask | modifier;
    }
    return stateMask;
  }

  /**
   * Creates a new Java Editor text hover descriptor from the given configuration element.
   *
   * @param element the configuration element
   */
  private JavaEditorTextHoverDescriptor(IConfigurationElement element) {
    Assert.isNotNull(element);
    fElement= element;
  }

  /**
   * Creates the Java editor text hover.
   *
   * @return the text hover
   */
  public IJavaEditorTextHover createTextHover() {
     String pluginId = fElement.getContributor().getName();
    boolean isHoversPlugInActivated= Platform.getBundle(pluginId).getState() == Bundle.ACTIVE;
    if (isHoversPlugInActivated || canActivatePlugIn()) {
      try {
        return (IJavaEditorTextHover)fElement.createExecutableExtension(CLASS_ATTRIBUTE);
      } catch (CoreException x) {
        JavaPlugin.log(new Status(IStatus.ERROR, JavaPlugin.getPluginId(), 0, JavaHoverMessages.JavaTextHover_createTextHover, null));
      }
    }

    return null;
  }

  //---- XML Attribute accessors ---------------------------------------------

  /**
   * Returns the hover's id.
   *
   * @return the id
   */
  public String getId() {
      return fElement.getAttribute(ID_ATTRIBUTE);
  }

  /**
   * Returns the hover's class name.
   *
   * @return the class name
   */
  public String getHoverClassName() {
    return fElement.getAttribute(CLASS_ATTRIBUTE);
  }

  /**
   * Returns the hover's label.
   *
   * @return the label
   */
  public String getLabel() {
    String label= fElement.getAttribute(LABEL_ATTRIBUTE);
    if (label != null)
      return label;

    // Return simple class name
    label= getHoverClassName();
    int lastDot= label.lastIndexOf('.');
    if (lastDot >= 0 && lastDot < label.length() - 1)
      return label.substring(lastDot + 1);
    else
      return label;
  }

  /**
   * Returns the hover's description.
   *
   * @return the hover's description or <code>null</code> if not provided
   */
  public String getDescription() {
    return fElement.getAttribute(DESCRIPTION_ATTRIBUTE);
  }


  public boolean canActivatePlugIn() {
    return Boolean.valueOf(fElement.getAttribute(ACTIVATE_PLUG_IN_ATTRIBUTE)).booleanValue();
  }

  public boolean equals(Object obj) {
    if (obj == null || !obj.getClass().equals(this.getClass()) || getId() == null)
      return false;
    return getId().equals(((JavaEditorTextHoverDescriptor)obj).getId());
  }

  public int hashCode() {
    return getId().hashCode();
  }

  private static JavaEditorTextHoverDescriptor[] createDescriptors(IConfigurationElement[] elements) {
    List result= new ArrayList(elements.length);
    for (int i= 0; i < elements.length; i++) {
      IConfigurationElement element= elements[i];
      if (HOVER_TAG.equals(element.getName())) {
        JavaEditorTextHoverDescriptor desc= new JavaEditorTextHoverDescriptor(element);
        result.add(desc);
      }
    }
    return (JavaEditorTextHoverDescriptor[])result.toArray(new JavaEditorTextHoverDescriptor[result.size()]);
  }

  private static void initializeFromPreferences(JavaEditorTextHoverDescriptor[] hovers) {
    String compiledTextHoverModifiers= JavaPlugin.getDefault().getPreferenceStore().getString(PreferenceConstants.EDITOR_TEXT_HOVER_MODIFIERS);

    StringTokenizer tokenizer= new StringTokenizer(compiledTextHoverModifiers, VALUE_SEPARATOR);
    HashMap idToModifier= new HashMap(tokenizer.countTokens() / 2);

    while (tokenizer.hasMoreTokens()) {
      String id= tokenizer.nextToken();
      if (tokenizer.hasMoreTokens())
        idToModifier.put(id, tokenizer.nextToken());
    }

    String compiledTextHoverModifierMasks= JavaPlugin.getDefault().getPreferenceStore().getString(PreferenceConstants.EDITOR_TEXT_HOVER_MODIFIER_MASKS);

    tokenizer= new StringTokenizer(compiledTextHoverModifierMasks, VALUE_SEPARATOR);
    HashMap idToModifierMask= new HashMap(tokenizer.countTokens() / 2);

    while (tokenizer.hasMoreTokens()) {
      String id= tokenizer.nextToken();
      if (tokenizer.hasMoreTokens())
        idToModifierMask.put(id, tokenizer.nextToken());
    }

    for (int i= 0; i < hovers.length; i++) {
      String modifierString= (String)idToModifier.get(hovers[i].getId());
      boolean enabled= true;
      if (modifierString == null)
        modifierString= DISABLED_TAG;

      if (modifierString.startsWith(DISABLED_TAG)) {
        enabled= false;
        modifierString= modifierString.substring(1);
      }

      if (modifierString.equals(NO_MODIFIER))
        modifierString= ""; //$NON-NLS-1$

      hovers[i].fModifierString= modifierString;
      hovers[i].fIsEnabled= enabled;
      hovers[i].fStateMask= computeStateMask(modifierString);
      if (hovers[i].fStateMask == -1) {
        // Fallback: use stored modifier masks
        try {
          hovers[i].fStateMask= Integer.parseInt((String)idToModifierMask.get(hovers[i].getId()));
        } catch (NumberFormatException ex) {
          hovers[i].fStateMask= -1;
        }
        // Fix modifier string
        int stateMask= hovers[i].fStateMask;
        if (stateMask == -1)
          hovers[i].fModifierString= ""; //$NON-NLS-1$
        else
          hovers[i].fModifierString= EditorUtility.getModifierString(stateMask);
      }
    }
  }

  /**
   * Returns the configured modifier getStateMask for this hover.
   *
   * @return the hover modifier stateMask or -1 if no hover is configured
   */
  public int getStateMask() {
    return fStateMask;
  }

  /**
   * Returns the modifier String as set in the preference store.
   *
   * @return the modifier string
   */
  public String getModifierString() {
    return fModifierString;
  }

  /**
   * Returns whether this hover is enabled or not.
   *
   * @return <code>true</code> if enabled
   */
  public boolean isEnabled() {
    return fIsEnabled;
  }

  /**
   * Returns this hover descriptors configuration element.
   *
   * @return the configuration element
   * @since 3.0
   */
  public IConfigurationElement getConfigurationElement() {
    return fElement;
  }
}