ipojo/runtime/core/src/main/java/org/apache/felix/ipojo/util/ContextSourceManager.java - felix - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
  *
  * 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 org.apache.felix.ipojo.util;

 import org.apache.felix.ipojo.ContextListener;
 import org.apache.felix.ipojo.ContextSource;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.InvalidSyntaxException;
 import org.osgi.framework.ServiceReference;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Dictionary;
 import java.util.List;

 /**
  * This class manages context-source management.
  *
  * @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
  */
 public class ContextSourceManager implements ContextListener {

     /**
      * The variable prefix
      */
     public static final String VARIABLE_START = "${";

     /**
      * The variable end
      */
     public static final char VARIABLE_END = '}';

     /**
      * List of characters forbidden in variable names
      */
     public static final List<Character> FORBIDDEN_CHARACTERS = Arrays.asList(
             '(', ')', '&', '|', '!', '=', '*', ' ');

     /**
      * Managed dependency.
      */
     private DependencyModel m_dependency;
     /**
      * List of monitored context sources.
      */
     private List<ContextSource> m_sources = new ArrayList<ContextSource>(1);
     /**
      * Variables contained in the original filter.
      */
     private List<String> m_variables;
     /**
      * Original filter (containing variables).
      */
     private String m_filter;
     /**
      * Bundle context.
      */
     private BundleContext m_context;
     /**
      * The Context-Source service tracker.
      */
     private Tracker m_tracker;

     /**
      * Creates the context source manager.
      *
      * @param dependency the dependency model on which this manager is plugged.
      */
     public ContextSourceManager(DependencyModel dependency) throws InvalidSyntaxException {
         m_filter = dependency.getFilter();
         m_variables = extractVariablesFromFilter(m_filter);
         m_dependency = dependency;
         m_context = dependency.getComponentInstance().getContext();
     }

     /**
      * This method substitutes ${var} substring by values stored in a map.
      *
      * @param str    : string with variables
      * @param values : dictionary containing the variable name and the value.
      * @return resulted string
      */
     public static String substitute(String str, Dictionary values) {
         int len = str.length();
         StringBuilder builder = new StringBuilder(len);

         int prev = 0;
         int start = str.indexOf("${");
         int end = str.indexOf('}', start);
         while (start != -1 && end != -1) {
             String key = str.substring(start + 2, end);
             Object value = values.get(key);
             if (value == null) {
                 builder.append(str.substring(prev, end + 1));
             } else {
                 builder.append(str.substring(prev, start));
                 builder.append(value);
             }
             prev = end + 1;
             if (prev >= str.length()) {
                 break;
             }

             start = str.indexOf("${", prev);
             if (start != -1) {
                 end = str.indexOf('}', start);
             }
         }

         builder.append(str.substring(prev));

         return builder.toString();
     }

     /**
      * Extracts the variables (${name}) from the given filter.
      *
      * @param filter : string form of the filter.
      * @return the list of found properties.
      * @throws InvalidSyntaxException thrown when the variables are not consistent.
      */
     public static List<String> extractVariablesFromFilter(String filter) throws InvalidSyntaxException {
         List<String> variables = new ArrayList<String>();
         int prev;
         int start = filter.indexOf(VARIABLE_START);
         int end = filter.indexOf(VARIABLE_END, start);
         while (start != -1) {
             // Unfinished variable
             if (end == -1) {
                 throw new InvalidSyntaxException("The filter contains an unfinished variable", filter);
             }

             String key = filter.substring(start + VARIABLE_START.length(), end);

             // Error detection :
             // Empty variable.
             if (key.length() == 0) {
                 throw new InvalidSyntaxException("The filter variable '${}' is not a valid " +
                         "variable", filter);
             }
             // Variable with spaces.
             Character forbidden = containsForbiddenCharacter(key);
             if (forbidden != null) {
                 throw new InvalidSyntaxException("The filter variable '${" + key + "}' contains a forbidden " +
                         "character : '" + forbidden + "'", filter);
             }


             variables.add(key);
             prev = end + 1;
             if (prev >= filter.length()) {
                 break;
             }

             start = filter.indexOf(VARIABLE_START, prev);
             if (start != -1) {
                 end = filter.indexOf(VARIABLE_END, start);
             }
         }

         return variables;
     }

     private static Character containsForbiddenCharacter(String key) {
         for (Character character : FORBIDDEN_CHARACTERS) {
             if (key.indexOf(character) != -1) {
                 return character;
             }
         }
         // Safe key.
         return null;
     }

     /**
      * Start the context management.
      */
     public void start() {
         if (m_tracker == null) {
             m_tracker = new Tracker(m_context, ContextSource.class.getName(), new SourceTracker());
         }
         m_tracker.open();
         computeFilter();
     }

     /**
      * Stop the context management.
      */
     public void stop() {
         if (m_tracker != null) {
             m_tracker.close();
             m_tracker = null;
         }
         // Reinitialize the filter.
         setFilter(m_filter);
         for (ContextSource source : m_sources) {
             source.unregisterContextListener(this);
         }
         m_sources.clear();
     }

     /**
      * Set the filter of the managed dependency.
      *
      * @param filter : the new filter to apply
      */
     private void setFilter(String filter) {
         if (!filter.equals(m_dependency.getFilter())) {
             // Reconfigure
             try {
                 m_dependency.setFilter(m_context.createFilter(filter));
             } catch (InvalidSyntaxException e) {
                 throw new IllegalStateException("A context filter is invalid : " + filter, e);
             }
         }
     }

     /**
      * Compute the new filter.
      */
     private void computeFilter() {
         String fil = m_filter; // Gets a copy.
         synchronized (this) {
             for (ContextSource m_source : m_sources) {
                 Dictionary props = m_source.getContext();
                 fil = substitute(fil, props); //NOPMD
             }
         }
         if (!fil.equals(m_dependency.getFilter())) {
             setFilter(fil);
         }
     }

     /**
      * A context source has modified a monitored property.
      *
      * @param source   : source
      * @param property : modified property
      * @param value    : new value.
      * @see org.apache.felix.ipojo.ContextListener#update(org.apache.felix.ipojo.ContextSource, String, Object)
      */
     public synchronized void update(ContextSource source, String property, Object value) {
         computeFilter();
     }

     /**
      * A context source appears.
      *
      * @param source : new context source.
      */
     public void addContextSource(ContextSource source) {
         m_sources.add(source);
         computeFilter();
         source.registerContextListener(this, m_variables.toArray(new String[m_variables.size()]));
     }

     /**
      * A context source disappears.
      *
      * @param source : leaving context source.
      */
     public void removeContextSource(ContextSource source) {
         source.unregisterContextListener(this);
         m_sources.remove(source);
         computeFilter();
     }

     private class SourceTracker implements TrackerCustomizer {
         /**
          * A new context-source was added.
          * This method inject the context-source object in the source manager.
          *
          * @param reference : service reference.
          * @see TrackerCustomizer#addedService(org.osgi.framework.ServiceReference)
          */
         public void addedService(ServiceReference reference) {
             addContextSource((ContextSource) m_tracker.getService(reference));
         }

         /**
          * A new context-source is adding in the tracker..
          *
          * @param reference : service reference
          * @return true.
          * @see TrackerCustomizer#addingService(org.osgi.framework.ServiceReference)
          */
         public boolean addingService(ServiceReference reference) {
             return true;
         }

         /**
          * A used context-source is modified.
          *
          * @param reference : service reference.
          * @param service   : service object.
          * @see TrackerCustomizer#modifiedService(org.osgi.framework.ServiceReference, Object)
          */
         public void modifiedService(ServiceReference reference, Object service) {
             // Nothing to do.
         }

         /**
          * A used context-source disappears.
          * This method notify the Source Manager in order to manage this departure.
          *
          * @param reference : service reference.
          * @param service   : service object.
          * @see TrackerCustomizer#modifiedService(org.osgi.framework.ServiceReference, Object)
          */
         public void removedService(ServiceReference reference, Object service) {
             removeContextSource((ContextSource) service);
         }

     }

 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
	*
	* 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 org.apache.felix.ipojo.util;

	import org.apache.felix.ipojo.ContextListener;
	import org.apache.felix.ipojo.ContextSource;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.InvalidSyntaxException;
	import org.osgi.framework.ServiceReference;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Dictionary;
	import java.util.List;

	/**
	* This class manages context-source management.
	*
	* @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
	*/
	public class ContextSourceManager implements ContextListener {

	/**
	* The variable prefix
	*/
	public static final String VARIABLE_START = "${";

	/**
	* The variable end
	*/
	public static final char VARIABLE_END = '}';

	/**
	* List of characters forbidden in variable names
	*/
	public static final List<Character> FORBIDDEN_CHARACTERS = Arrays.asList(
	'(', ')', '&', '\|', '!', '=', '*', ' ');

	/**
	* Managed dependency.
	*/
	private DependencyModel m_dependency;
	/**
	* List of monitored context sources.
	*/
	private List<ContextSource> m_sources = new ArrayList<ContextSource>(1);
	/**
	* Variables contained in the original filter.
	*/
	private List<String> m_variables;
	/**
	* Original filter (containing variables).
	*/
	private String m_filter;
	/**
	* Bundle context.
	*/
	private BundleContext m_context;
	/**
	* The Context-Source service tracker.
	*/
	private Tracker m_tracker;

	/**
	* Creates the context source manager.
	*
	* @param dependency the dependency model on which this manager is plugged.
	*/
	public ContextSourceManager(DependencyModel dependency) throws InvalidSyntaxException {
	m_filter = dependency.getFilter();
	m_variables = extractVariablesFromFilter(m_filter);
	m_dependency = dependency;
	m_context = dependency.getComponentInstance().getContext();
	}

	/**
	* This method substitutes ${var} substring by values stored in a map.
	*
	* @param str : string with variables
	* @param values : dictionary containing the variable name and the value.
	* @return resulted string
	*/
	public static String substitute(String str, Dictionary values) {
	int len = str.length();
	StringBuilder builder = new StringBuilder(len);

	int prev = 0;
	int start = str.indexOf("${");
	int end = str.indexOf('}', start);
	while (start != -1 && end != -1) {
	String key = str.substring(start + 2, end);
	Object value = values.get(key);
	if (value == null) {
	builder.append(str.substring(prev, end + 1));
	} else {
	builder.append(str.substring(prev, start));
	builder.append(value);
	}
	prev = end + 1;
	if (prev >= str.length()) {
	break;
	}

	start = str.indexOf("${", prev);
	if (start != -1) {
	end = str.indexOf('}', start);
	}
	}

	builder.append(str.substring(prev));

	return builder.toString();
	}

	/**
	* Extracts the variables (${name}) from the given filter.
	*
	* @param filter : string form of the filter.
	* @return the list of found properties.
	* @throws InvalidSyntaxException thrown when the variables are not consistent.
	*/
	public static List<String> extractVariablesFromFilter(String filter) throws InvalidSyntaxException {
	List<String> variables = new ArrayList<String>();
	int prev;
	int start = filter.indexOf(VARIABLE_START);
	int end = filter.indexOf(VARIABLE_END, start);
	while (start != -1) {
	// Unfinished variable
	if (end == -1) {
	throw new InvalidSyntaxException("The filter contains an unfinished variable", filter);
	}

	String key = filter.substring(start + VARIABLE_START.length(), end);

	// Error detection :
	// Empty variable.
	if (key.length() == 0) {
	throw new InvalidSyntaxException("The filter variable '${}' is not a valid " +
	"variable", filter);
	}
	// Variable with spaces.
	Character forbidden = containsForbiddenCharacter(key);
	if (forbidden != null) {
	throw new InvalidSyntaxException("The filter variable '${" + key + "}' contains a forbidden " +
	"character : '" + forbidden + "'", filter);
	}


	variables.add(key);
	prev = end + 1;
	if (prev >= filter.length()) {
	break;
	}

	start = filter.indexOf(VARIABLE_START, prev);
	if (start != -1) {
	end = filter.indexOf(VARIABLE_END, start);
	}
	}

	return variables;
	}

	private static Character containsForbiddenCharacter(String key) {
	for (Character character : FORBIDDEN_CHARACTERS) {
	if (key.indexOf(character) != -1) {
	return character;
	}
	}
	// Safe key.
	return null;
	}

	/**
	* Start the context management.
	*/
	public void start() {
	if (m_tracker == null) {
	m_tracker = new Tracker(m_context, ContextSource.class.getName(), new SourceTracker());
	}
	m_tracker.open();
	computeFilter();
	}

	/**
	* Stop the context management.
	*/
	public void stop() {
	if (m_tracker != null) {
	m_tracker.close();
	m_tracker = null;
	}
	// Reinitialize the filter.
	setFilter(m_filter);
	for (ContextSource source : m_sources) {
	source.unregisterContextListener(this);
	}
	m_sources.clear();
	}

	/**
	* Set the filter of the managed dependency.
	*
	* @param filter : the new filter to apply
	*/
	private void setFilter(String filter) {
	if (!filter.equals(m_dependency.getFilter())) {
	// Reconfigure
	try {
	m_dependency.setFilter(m_context.createFilter(filter));
	} catch (InvalidSyntaxException e) {
	throw new IllegalStateException("A context filter is invalid : " + filter, e);
	}
	}
	}

	/**
	* Compute the new filter.
	*/
	private void computeFilter() {
	String fil = m_filter; // Gets a copy.
	synchronized (this) {
	for (ContextSource m_source : m_sources) {
	Dictionary props = m_source.getContext();
	fil = substitute(fil, props); //NOPMD
	}
	}
	if (!fil.equals(m_dependency.getFilter())) {
	setFilter(fil);
	}
	}

	/**
	* A context source has modified a monitored property.
	*
	* @param source : source
	* @param property : modified property
	* @param value : new value.
	* @see org.apache.felix.ipojo.ContextListener#update(org.apache.felix.ipojo.ContextSource, String, Object)
	*/
	public synchronized void update(ContextSource source, String property, Object value) {
	computeFilter();
	}

	/**
	* A context source appears.
	*
	* @param source : new context source.
	*/
	public void addContextSource(ContextSource source) {
	m_sources.add(source);
	computeFilter();
	source.registerContextListener(this, m_variables.toArray(new String[m_variables.size()]));
	}

	/**
	* A context source disappears.
	*
	* @param source : leaving context source.
	*/
	public void removeContextSource(ContextSource source) {
	source.unregisterContextListener(this);
	m_sources.remove(source);
	computeFilter();
	}

	private class SourceTracker implements TrackerCustomizer {
	/**
	* A new context-source was added.
	* This method inject the context-source object in the source manager.
	*
	* @param reference : service reference.
	* @see TrackerCustomizer#addedService(org.osgi.framework.ServiceReference)
	*/
	public void addedService(ServiceReference reference) {
	addContextSource((ContextSource) m_tracker.getService(reference));
	}

	/**
	* A new context-source is adding in the tracker..
	*
	* @param reference : service reference
	* @return true.
	* @see TrackerCustomizer#addingService(org.osgi.framework.ServiceReference)
	*/
	public boolean addingService(ServiceReference reference) {
	return true;
	}

	/**
	* A used context-source is modified.
	*
	* @param reference : service reference.
	* @param service : service object.
	* @see TrackerCustomizer#modifiedService(org.osgi.framework.ServiceReference, Object)
	*/
	public void modifiedService(ServiceReference reference, Object service) {
	// Nothing to do.
	}

	/**
	* A used context-source disappears.
	* This method notify the Source Manager in order to manage this departure.
	*
	* @param reference : service reference.
	* @param service : service object.
	* @see TrackerCustomizer#modifiedService(org.osgi.framework.ServiceReference, Object)
	*/
	public void removedService(ServiceReference reference, Object service) {
	removeContextSource((ContextSource) service);
	}

	}

	}