Merge pull request #15 from gitblit/requires

Add an optional requires manifest value

pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java

@@ -89,6 +89,11 @@ public class DefaultPluginManager implements PluginManager {
      */
     private RuntimeMode runtimeMode;
 
+    /**
+     * The system version used for comparisons to the plugin requires attribute.
+     */
+    private PluginVersion systemVersion = PluginVersion.ZERO;
+
     /**
      * The plugins directory is supplied by System.getProperty("pf4j.pluginsDir", "plugins").
      */
@@ -110,6 +115,16 @@ public class DefaultPluginManager implements PluginManager {
         initialize();
     }
 
+    @Override
+    public void setSystemVersion(PluginVersion version) {
+    	systemVersion = version;
+    }
+
+    @Override
+    public PluginVersion getSystemVersion() {
+    	return systemVersion;
+    }
+
 	@Override
     public List<PluginWrapper> getPlugins() {
         return new ArrayList<PluginWrapper>(plugins.values());
@@ -454,10 +469,17 @@ public class DefaultPluginManager implements PluginManager {
         }
 
         PluginWrapper pluginWrapper = getPlugin(pluginId);
+       	if (!isPluginValid(pluginWrapper)) {
+        	log.warn("Plugin '{}:{}' can not be enabled",
+        			pluginWrapper.getPluginId(),
+        			pluginWrapper.getDescriptor().getVersion());
+            return false;
+        }
+
         PluginDescriptor pluginDescriptor = pluginWrapper.getDescriptor();
         PluginState pluginState = pluginWrapper.getPluginState();
         if (PluginState.DISABLED != pluginState) {
-            log.debug("Plugin plugin '{}:{}' is not disabled", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
+            log.debug("Plugin '{}:{}' is not disabled", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
             return true;
         }
 
@@ -634,6 +656,20 @@ public class DefaultPluginManager implements PluginManager {
     	return !enabledPlugins.contains(pluginId);
     }
 
+    protected boolean isPluginValid(PluginWrapper pluginWrapper) {
+    	PluginVersion requires = pluginWrapper.getDescriptor().getRequires();
+    	PluginVersion system = getSystemVersion();
+    	if (system.isZero() || system.atLeast(requires)) {
+    		return true;
+    	}
+
+    	log.warn(String.format("Plugin '%s:%s' requires a minimum system version of %s",
+    			pluginWrapper.getPluginId(),
+    			pluginWrapper.getDescriptor().getVersion(),
+    			requires));
+    	return false;
+    }
+
     protected FileFilter createHiddenPluginFilter() {
     	return new HiddenFilter();
     }
@@ -724,6 +760,12 @@ public class DefaultPluginManager implements PluginManager {
             pluginWrapper.setPluginState(PluginState.DISABLED);
         }
 
+        // validate the plugin
+        if (!isPluginValid(pluginWrapper)) {
+        	log.info("Plugin '{}' is disabled", pluginPath);
+        	pluginWrapper.setPluginState(PluginState.DISABLED);
+        }
+
         log.debug("Created wrapper '{}' for plugin '{}'", pluginWrapper, pluginPath);
 
         String pluginId = pluginDescriptor.getPluginId();

pf4j/src/main/java/ro/fortsoft/pf4j/ManifestPluginDescriptorFinder.java

@@ -103,6 +103,11 @@ public class ManifestPluginDescriptorFinder implements PluginDescriptorFinder {
         String dependencies = attrs.getValue("Plugin-Dependencies");
         pluginDescriptor.setDependencies(dependencies);
 
+        String requires = attrs.getValue("Plugin-Requires");
+        if (StringUtils.isNotEmpty(requires)) {
+        	pluginDescriptor.setRequires(PluginVersion.createVersion(requires));
+        }
+
 		return pluginDescriptor;
 	}
 

pf4j/src/main/java/ro/fortsoft/pf4j/PluginDescriptor.java

@@ -28,10 +28,12 @@ public class PluginDescriptor {
 	private String pluginDescription;
     private String pluginClass;
     private PluginVersion version;
+    private PluginVersion requires;
     private String provider;
     private List<PluginDependency> dependencies;
 
     public PluginDescriptor() {
+    	requires = PluginVersion.ZERO;
         dependencies = new ArrayList<PluginDependency>();
     }
 
@@ -63,6 +65,13 @@ public class PluginDescriptor {
         return version;
     }
 
+    /**
+     * Returns the requires of this plugin.
+     */
+    public PluginVersion getRequires() {
+        return requires;
+    }
+
     /**
      * Returns the provider name of this plugin.
      */
@@ -106,6 +115,10 @@ public class PluginDescriptor {
         this.provider = provider;
     }
 
+    void setRequires(PluginVersion requires) {
+        this.requires = requires;
+    }
+
     void setDependencies(String dependencies) {
     	if (dependencies != null) {
     		dependencies = dependencies.trim();

pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java

@@ -141,4 +141,20 @@ public interface PluginManager {
 
     public void removePluginStateListener(PluginStateListener listener);
 
+    /**
+     * Set the system version.  This is used to compare against the plugin
+     * requires attribute.  The default system version is 0.0.0 which
+     * disables all version checking.
+     *
+     * @default 0.0.0
+     * @param version
+     */
+    public void setSystemVersion(PluginVersion version);
+
+    /**
+     * Returns the system version.
+     *
+     * * @return the system version
+     */
+    public PluginVersion getSystemVersion();
 }

pf4j/src/main/java/ro/fortsoft/pf4j/PluginVersion.java

@@ -1,22 +1,22 @@
 /*
  * Copyright 2012 Decebal Suiu
- * 
+ *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
  * the License. You may obtain a copy of the License in the LICENSE file, or 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 ro.fortsoft.pf4j;
 
-import ro.fortsoft.pf4j.util.StringUtils;
-
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import ro.fortsoft.pf4j.util.StringUtils;
+
 /**
  * Represents the version of a Plugin and allows versions to be compared.
  * Version following semantic defined by <a href="http://semver.org/">Semantic Versioning</a> document.
@@ -33,6 +33,8 @@ import java.util.regex.Pattern;
  */
 public class PluginVersion implements Comparable<PluginVersion> {
 
+	public static final PluginVersion ZERO = new PluginVersion(0, 0, 0);
+
     private static final String FORMAT = "(\\d+)\\.(\\d+)(?:\\.)?(\\d*)(\\.|-|\\+)?([0-9A-Za-z-.]*)?";
     private static final Pattern PATTERN = Pattern.compile(FORMAT);
 
@@ -95,6 +97,7 @@ public class PluginVersion implements Comparable<PluginVersion> {
 		return qualifier;
 	}
 
+	@Override
 	public String toString() {
         StringBuffer sb = new StringBuffer(50);
         sb.append(major);
@@ -135,6 +138,18 @@ public class PluginVersion implements Comparable<PluginVersion> {
         return 0;
     }
 
+    public boolean isZero() {
+    	return compareTo(ZERO) == 0;
+    }
+
+    public boolean atLeast(PluginVersion v) {
+    	return compareTo(v) <= 0;
+    }
+
+    public boolean exceeds(PluginVersion v) {
+    	return compareTo(v) > 0;
+    }
+
     // for test only
     public static void main(String[] args) {
         PluginVersion v = PluginVersion.createVersion("1.2.3-SNAPSHOT");