RegisteredPolicy.java :  » IDE-Eclipse » osgi » org » eclipse » osgi » internal » loader » buddy » Java Open Source

/*******************************************************************************
 * Copyright (c) 2005, 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.osgi.internal.loader.buddy;

import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;
import java.util.Iterator;
import org.eclipse.osgi.framework.internal.core.AbstractBundle;
import org.eclipse.osgi.framework.internal.core.Constants;
import org.eclipse.osgi.internal.loader.BundleLoader;
import org.eclipse.osgi.internal.loader.BundleLoaderProxy;
import org.eclipse.osgi.service.resolver.BundleDescription;
import org.eclipse.osgi.util.ManifestElement;
import org.osgi.framework.BundleException;

/**
 *Registered policy is an implementation of a buddy policy. 
 * It is responsible for looking up a class in the bundles (registrant) that declare interest in the bundle that require the buddy loading.
 * Note that the registrants must have a direct dependency on the bundle needing buddy.
 */
public class RegisteredPolicy extends DependentPolicy {

  public RegisteredPolicy(BundleLoader requester) {
    super(requester);

    //Filter the dependents;
    if (allDependents == null)
      return;

    for (Iterator iter = allDependents.iterator(); iter.hasNext();) {
      BundleLoaderProxy proxy = buddyRequester.getLoaderProxy((BundleDescription) iter.next());
      if (proxy == null)
        iter.remove();

      try {
        String[] allContributions = ManifestElement.getArrayFromList((String) ((AbstractBundle) proxy.getBundle()).getBundleData().getManifest().get(Constants.REGISTERED_POLICY));
        if (allContributions == null) {
          iter.remove();
          continue;
        }
        boolean contributes = false;
        for (int j = 0; j < allContributions.length && contributes == false; j++) {
          if (allContributions[j].equals(buddyRequester.getBundle().getSymbolicName()))
            contributes = true;
        }
        if (!contributes)
          iter.remove();

      } catch (BundleException e) {
        iter.remove();
      }
    }

    //After the filtering, if nothing is left then null out the variable for optimization
    if (allDependents.size() == 0)
      allDependents = null;
  }

  public Class loadClass(String name) {
    if (allDependents == null)
      return null;

    Class result = null;
    int size = allDependents.size();
    for (int i = 0; i < size && result == null; i++) {
      try {
        BundleLoaderProxy proxy = buddyRequester.getLoaderProxy((BundleDescription) allDependents.get(i));
        if (proxy == null)
          continue;
        result = proxy.getBundleLoader().findClass(name);
      } catch (ClassNotFoundException e) {
        //Nothing to do, just keep looking
        continue;
      }
    }
    return result;
  }

  public URL loadResource(String name) {
    if (allDependents == null)
      return null;

    URL result = null;
    int size = allDependents.size();
    for (int i = 0; i < size && result == null; i++) {
      BundleLoaderProxy proxy = buddyRequester.getLoaderProxy((BundleDescription) allDependents.get(i));
      if (proxy == null)
        continue;
      result = proxy.getBundleLoader().findResource(name);
    }
    return result;
  }

  public Enumeration loadResources(String name) {
    if (allDependents == null)
      return null;

    Enumeration results = null;
    int size = allDependents.size();
    for (int i = 0; i < size; i++) {
      try {
        BundleLoaderProxy proxy = buddyRequester.getLoaderProxy((BundleDescription) allDependents.get(i));
        if (proxy == null)
          continue;
        results = BundleLoader.compoundEnumerations(results, proxy.getBundleLoader().findResources(name));
      } catch (IOException e) {
        //Ignore and keep looking
      }
    }
    return results;
  }
}