src/main/java/org/apache/commons/jexl3/internal/introspection/ClassMap.java - commons-jexl - 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.commons.jexl3.internal.introspection;

 import org.apache.commons.logging.Log;

 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;

 /**
  * A cache of introspection information for a specific class instance.
  * Keys objects by an aggregation of the method name and the classes
  * that make up the parameters.
  * <p>
  * Originally taken from the Velocity tree so we can be self-sufficient.
  * </p>
  * @see MethodKey
  * @since 1.0
  */
 final class ClassMap {
     /**
      * A method that returns itself used as a marker for cache miss,
      * allows the underlying cache map to be strongly typed.
      * @return itself as a method
      */
     public static Method cacheMiss() {
         try {
             return ClassMap.class.getMethod("cacheMiss");
         } catch (Exception xio) {
             // this really cant make an error...
             return null;
         }
     }

     /** The cache miss marker method. */
     private static final Method CACHE_MISS = cacheMiss();
     /**
      * This is the cache to store and look up the method information.
      * <p>
      * It stores the association between:
      * - a key made of a method name and an array of argument types.
      * - a method.
      * </p>
      * <p>
      * Since the invocation of the associated method is dynamic, there is no need (nor way) to differentiate between
      * foo(int,int) and foo(Integer,Integer) since in practice only the latter form will be used through a call.
      * This of course, applies to all 8 primitive types.
      * </p>
      * Uses ConcurrentMap since 3.0, marginally faster than 2.1 under contention.
      */
     private final ConcurrentMap<MethodKey, Method> byKey = new ConcurrentHashMap<MethodKey, Method>();
     /**
      * Keep track of all methods with the same name; this is not modified after creation.
      */
     private final Map<String, Method[]> byName = new HashMap<String, Method[]>();
     /**
      * Cache of fields.
      */
     private final Map<String, Field> fieldCache;

     /**
      * Standard constructor.
      *
      * @param aClass the class to deconstruct.
      * @param permissions the permissions to apply during introspection
      * @param log    the logger.
      */
     @SuppressWarnings("LeakingThisInConstructor")
     ClassMap(Class<?> aClass, Permissions permissions, Log log) {
         // eagerly cache methods
         create(this, permissions, aClass, log);
         // eagerly cache public fields
         Field[] fields = aClass.getFields();
         if (fields.length > 0) {
             Map<String, Field> cache = new HashMap<String, Field>();
             for (Field field : fields) {
                 if (permissions.allow(field)) {
                     cache.put(field.getName(), field);
                 }
             }
             fieldCache = cache;
         } else {
             fieldCache = Collections.emptyMap();
         }
     }

     /**
      * Find a Field using its name.
      * @param fname the field name
      * @return A Field object representing the field to invoke or null.
      */
     Field getField(final String fname) {
         return fieldCache.get(fname);
     }

     /**
      * Gets the field names cached by this map.
      * @return the array of field names
      */
     String[] getFieldNames() {
         return fieldCache.keySet().toArray(new String[fieldCache.size()]);
     }

     /**
      * Gets the methods names cached by this map.
      * @return the array of method names
      */
     String[] getMethodNames() {
         return byName.keySet().toArray(new String[byName.size()]);
     }

     /**
      * Gets all the methods with a given name from this map.
      * @param methodName the seeked methods name
      * @return the array of methods (null or non-empty)
      */
     Method[] getMethods(final String methodName) {
         Method[] lm = byName.get(methodName);
         if (lm != null && lm.length > 0) {
             return lm.clone();
         } else {
             return null;
         }
     }

     /**
      * Find a Method using the method name and parameter objects.
      * <p>
      * Look in the methodMap for an entry. If found,
      * it'll either be a CACHE_MISS, in which case we
      * simply give up, or it'll be a Method, in which
      * case, we return it.
      * </p>
      * <p>
      * If nothing is found, then we must actually go
      * and introspect the method from the MethodMap.
      * </p>
      * @param methodKey the method key
      * @return A Method object representing the method to invoke or null.
      * @throws MethodKey.AmbiguousException When more than one method is a match for the parameters.
      */
     Method getMethod(final MethodKey methodKey) throws MethodKey.AmbiguousException {
         // Look up by key
         Method cacheEntry = byKey.get(methodKey);
         // We looked this up before and failed.
         if (cacheEntry == CACHE_MISS) {
             return null;
         } else if (cacheEntry == null) {
             try {
                 // That one is expensive...
                 Method[] methodList = byName.get(methodKey.getMethod());
                 if (methodList != null) {
                     cacheEntry = methodKey.getMostSpecificMethod(methodList);
                 }
                 if (cacheEntry == null) {
                     byKey.put(methodKey, CACHE_MISS);
                 } else {
                     byKey.put(methodKey, cacheEntry);
                 }
             } catch (MethodKey.AmbiguousException ae) {
                 // that's a miss :-)
                 byKey.put(methodKey, CACHE_MISS);
                 throw ae;
             }
         }

         // Yes, this might just be null.
         return cacheEntry;
     }

     /**
      * Populate the Map of direct hits. These are taken from all the public methods
      * that our class, its parents and their implemented interfaces provide.
      * @param cache          the ClassMap instance we create
      * @param permissions    the permissions to apply during introspection
      * @param classToReflect the class to cache
      * @param log            the Log
      */
     private static void create(ClassMap cache, Permissions permissions, Class<?> classToReflect, Log log) {
         //
         // Build a list of all elements in the class hierarchy. This one is bottom-first (i.e. we start
         // with the actual declaring class and its interfaces and then move up (superclass etc.) until we
         // hit java.lang.Object. That is important because it will give us the methods of the declaring class
         // which might in turn be abstract further up the tree.
         //
         // We also ignore all SecurityExceptions that might happen due to SecurityManager restrictions.
         //
         for (; classToReflect != null; classToReflect = classToReflect.getSuperclass()) {
             if (Modifier.isPublic(classToReflect.getModifiers())) {
                 populateWithClass(cache, permissions, classToReflect, log);
             }
             Class<?>[] interfaces = classToReflect.getInterfaces();
             for (int i = 0; i < interfaces.length; i++) {
                 populateWithInterface(cache, permissions, interfaces[i], log);
             }
         }
         // now that we've got all methods keyed in, lets organize them by name
         if (!cache.byKey.isEmpty()) {
             List<Method> lm = new ArrayList<Method>(cache.byKey.size());
             for (Method method : cache.byKey.values()) {
                 lm.add(method);
             }
             // sort all methods by name
             Collections.sort(lm, new Comparator<Method>() {
                 @Override
                 public int compare(Method o1, Method o2) {
                     return o1.getName().compareTo(o2.getName());
                 }
             });
             // put all lists of methods with same name in byName cache
             int start = 0;
             while (start < lm.size()) {
                 String name = lm.get(start).getName();
                 int end = start + 1;
                 while (end < lm.size()) {
                     String walk = lm.get(end).getName();
                     if (walk.equals(name)) {
                         end += 1;
                     } else {
                         break;
                     }
                 }
                 Method[] lmn = lm.subList(start, end).toArray(new Method[end - start]);
                 cache.byName.put(name, lmn);
                 start = end;
             }
         }
     }

     /**
      * Recurses up interface hierarchy to get all super interfaces.
      * @param cache the cache to fill
      * @param permissions the permissions to apply during introspection
      * @param iface the interface to populate the cache from
      * @param log   the Log
      */
     private static void populateWithInterface(ClassMap cache, Permissions permissions, Class<?> iface, Log log) {
         if (Modifier.isPublic(iface.getModifiers())) {
             populateWithClass(cache, permissions, iface, log);
             Class<?>[] supers = iface.getInterfaces();
             for (int i = 0; i < supers.length; i++) {
                 populateWithInterface(cache, permissions, supers[i], log);
             }
         }
     }

     /**
      * Recurses up class hierarchy to get all super classes.
      * @param cache the cache to fill
      * @param permissions the permissions to apply during introspection
      * @param clazz the class to populate the cache from
      * @param log   the Log
      */
     private static void populateWithClass(ClassMap cache, Permissions permissions, Class<?> clazz, Log log) {
         try {
             Method[] methods = clazz.getDeclaredMethods();
             for (int i = 0; i < methods.length; i++) {
                 Method mi = methods[i];
                 if (permissions.allow(mi)) {
                     // add method to byKey cache; do not override
                     MethodKey key = new MethodKey(mi);
                     Method pmi = cache.byKey.putIfAbsent(key, mi);
                     if (pmi != null && log.isDebugEnabled() && !key.equals(new MethodKey(pmi))) {
                         // foo(int) and foo(Integer) have the same signature for JEXL
                         log.debug("Method "+ pmi + " is already registered, key: " + key.debugString());
                     }
                 }
             }
         } catch (SecurityException se) {
             // Everybody feels better with...
             if (log.isDebugEnabled()) {
                 log.debug("While accessing methods of " + clazz + ": ", se);
             }
         }
     }
 }
	/*
	* 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.commons.jexl3.internal.introspection;

	import org.apache.commons.logging.Log;

	import java.lang.reflect.Field;
	import java.lang.reflect.Method;
	import java.lang.reflect.Modifier;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	import java.util.concurrent.ConcurrentHashMap;
	import java.util.concurrent.ConcurrentMap;

	/**
	* A cache of introspection information for a specific class instance.
	* Keys objects by an aggregation of the method name and the classes
	* that make up the parameters.
	* <p>
	* Originally taken from the Velocity tree so we can be self-sufficient.
	* </p>
	* @see MethodKey
	* @since 1.0
	*/
	final class ClassMap {
	/**
	* A method that returns itself used as a marker for cache miss,
	* allows the underlying cache map to be strongly typed.
	* @return itself as a method
	*/
	public static Method cacheMiss() {
	try {
	return ClassMap.class.getMethod("cacheMiss");
	} catch (Exception xio) {
	// this really cant make an error...
	return null;
	}
	}

	/** The cache miss marker method. */
	private static final Method CACHE_MISS = cacheMiss();
	/**
	* This is the cache to store and look up the method information.
	* <p>
	* It stores the association between:
	* - a key made of a method name and an array of argument types.
	* - a method.
	* </p>
	* <p>
	* Since the invocation of the associated method is dynamic, there is no need (nor way) to differentiate between
	* foo(int,int) and foo(Integer,Integer) since in practice only the latter form will be used through a call.
	* This of course, applies to all 8 primitive types.
	* </p>
	* Uses ConcurrentMap since 3.0, marginally faster than 2.1 under contention.
	*/
	private final ConcurrentMap<MethodKey, Method> byKey = new ConcurrentHashMap<MethodKey, Method>();
	/**
	* Keep track of all methods with the same name; this is not modified after creation.
	*/
	private final Map<String, Method[]> byName = new HashMap<String, Method[]>();
	/**
	* Cache of fields.
	*/
	private final Map<String, Field> fieldCache;

	/**
	* Standard constructor.
	*
	* @param aClass the class to deconstruct.
	* @param permissions the permissions to apply during introspection
	* @param log the logger.
	*/
	@SuppressWarnings("LeakingThisInConstructor")
	ClassMap(Class<?> aClass, Permissions permissions, Log log) {
	// eagerly cache methods
	create(this, permissions, aClass, log);
	// eagerly cache public fields
	Field[] fields = aClass.getFields();
	if (fields.length > 0) {
	Map<String, Field> cache = new HashMap<String, Field>();
	for (Field field : fields) {
	if (permissions.allow(field)) {
	cache.put(field.getName(), field);
	}
	}
	fieldCache = cache;
	} else {
	fieldCache = Collections.emptyMap();
	}
	}

	/**
	* Find a Field using its name.
	* @param fname the field name
	* @return A Field object representing the field to invoke or null.
	*/
	Field getField(final String fname) {
	return fieldCache.get(fname);
	}

	/**
	* Gets the field names cached by this map.
	* @return the array of field names
	*/
	String[] getFieldNames() {
	return fieldCache.keySet().toArray(new String[fieldCache.size()]);
	}

	/**
	* Gets the methods names cached by this map.
	* @return the array of method names
	*/
	String[] getMethodNames() {
	return byName.keySet().toArray(new String[byName.size()]);
	}

	/**
	* Gets all the methods with a given name from this map.
	* @param methodName the seeked methods name
	* @return the array of methods (null or non-empty)
	*/
	Method[] getMethods(final String methodName) {
	Method[] lm = byName.get(methodName);
	if (lm != null && lm.length > 0) {
	return lm.clone();
	} else {
	return null;
	}
	}

	/**
	* Find a Method using the method name and parameter objects.
	* <p>
	* Look in the methodMap for an entry. If found,
	* it'll either be a CACHE_MISS, in which case we
	* simply give up, or it'll be a Method, in which
	* case, we return it.
	* </p>
	* <p>
	* If nothing is found, then we must actually go
	* and introspect the method from the MethodMap.
	* </p>
	* @param methodKey the method key
	* @return A Method object representing the method to invoke or null.
	* @throws MethodKey.AmbiguousException When more than one method is a match for the parameters.
	*/
	Method getMethod(final MethodKey methodKey) throws MethodKey.AmbiguousException {
	// Look up by key
	Method cacheEntry = byKey.get(methodKey);
	// We looked this up before and failed.
	if (cacheEntry == CACHE_MISS) {
	return null;
	} else if (cacheEntry == null) {
	try {
	// That one is expensive...
	Method[] methodList = byName.get(methodKey.getMethod());
	if (methodList != null) {
	cacheEntry = methodKey.getMostSpecificMethod(methodList);
	}
	if (cacheEntry == null) {
	byKey.put(methodKey, CACHE_MISS);
	} else {
	byKey.put(methodKey, cacheEntry);
	}
	} catch (MethodKey.AmbiguousException ae) {
	// that's a miss :-)
	byKey.put(methodKey, CACHE_MISS);
	throw ae;
	}
	}

	// Yes, this might just be null.
	return cacheEntry;
	}

	/**
	* Populate the Map of direct hits. These are taken from all the public methods
	* that our class, its parents and their implemented interfaces provide.
	* @param cache the ClassMap instance we create
	* @param permissions the permissions to apply during introspection
	* @param classToReflect the class to cache
	* @param log the Log
	*/
	private static void create(ClassMap cache, Permissions permissions, Class<?> classToReflect, Log log) {
	//
	// Build a list of all elements in the class hierarchy. This one is bottom-first (i.e. we start
	// with the actual declaring class and its interfaces and then move up (superclass etc.) until we
	// hit java.lang.Object. That is important because it will give us the methods of the declaring class
	// which might in turn be abstract further up the tree.
	//
	// We also ignore all SecurityExceptions that might happen due to SecurityManager restrictions.
	//
	for (; classToReflect != null; classToReflect = classToReflect.getSuperclass()) {
	if (Modifier.isPublic(classToReflect.getModifiers())) {
	populateWithClass(cache, permissions, classToReflect, log);
	}
	Class<?>[] interfaces = classToReflect.getInterfaces();
	for (int i = 0; i < interfaces.length; i++) {
	populateWithInterface(cache, permissions, interfaces[i], log);
	}
	}
	// now that we've got all methods keyed in, lets organize them by name
	if (!cache.byKey.isEmpty()) {
	List<Method> lm = new ArrayList<Method>(cache.byKey.size());
	for (Method method : cache.byKey.values()) {
	lm.add(method);
	}
	// sort all methods by name
	Collections.sort(lm, new Comparator<Method>() {
	@Override
	public int compare(Method o1, Method o2) {
	return o1.getName().compareTo(o2.getName());
	}
	});
	// put all lists of methods with same name in byName cache
	int start = 0;
	while (start < lm.size()) {
	String name = lm.get(start).getName();
	int end = start + 1;
	while (end < lm.size()) {
	String walk = lm.get(end).getName();
	if (walk.equals(name)) {
	end += 1;
	} else {
	break;
	}
	}
	Method[] lmn = lm.subList(start, end).toArray(new Method[end - start]);
	cache.byName.put(name, lmn);
	start = end;
	}
	}
	}

	/**
	* Recurses up interface hierarchy to get all super interfaces.
	* @param cache the cache to fill
	* @param permissions the permissions to apply during introspection
	* @param iface the interface to populate the cache from
	* @param log the Log
	*/
	private static void populateWithInterface(ClassMap cache, Permissions permissions, Class<?> iface, Log log) {
	if (Modifier.isPublic(iface.getModifiers())) {
	populateWithClass(cache, permissions, iface, log);
	Class<?>[] supers = iface.getInterfaces();
	for (int i = 0; i < supers.length; i++) {
	populateWithInterface(cache, permissions, supers[i], log);
	}
	}
	}

	/**
	* Recurses up class hierarchy to get all super classes.
	* @param cache the cache to fill
	* @param permissions the permissions to apply during introspection
	* @param clazz the class to populate the cache from
	* @param log the Log
	*/
	private static void populateWithClass(ClassMap cache, Permissions permissions, Class<?> clazz, Log log) {
	try {
	Method[] methods = clazz.getDeclaredMethods();
	for (int i = 0; i < methods.length; i++) {
	Method mi = methods[i];
	if (permissions.allow(mi)) {
	// add method to byKey cache; do not override
	MethodKey key = new MethodKey(mi);
	Method pmi = cache.byKey.putIfAbsent(key, mi);
	if (pmi != null && log.isDebugEnabled() && !key.equals(new MethodKey(pmi))) {
	// foo(int) and foo(Integer) have the same signature for JEXL
	log.debug("Method "+ pmi + " is already registered, key: " + key.debugString());
	}
	}
	}
	} catch (SecurityException se) {
	// Everybody feels better with...
	if (log.isDebugEnabled()) {
	log.debug("While accessing methods of " + clazz + ": ", se);
	}
	}
	}
	}