src/main/java/freemarker/ext/beans/ClassIntrospectorBuilder.java - freemarker - 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 freemarker.ext.beans;

 import java.lang.ref.Reference;
 import java.lang.ref.ReferenceQueue;
 import java.lang.ref.WeakReference;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;

 import freemarker.template.Configuration;
 import freemarker.template.Version;
 import freemarker.template._TemplateAPI;
 import freemarker.template.utility.NullArgumentException;

 final class ClassIntrospectorBuilder implements Cloneable {

     private static final Map<ClassIntrospectorBuilder, Reference<ClassIntrospector>> INSTANCE_CACHE
             = new HashMap<ClassIntrospectorBuilder, Reference<ClassIntrospector>>();
     private static final ReferenceQueue<ClassIntrospector> INSTANCE_CACHE_REF_QUEUE
             = new ReferenceQueue<ClassIntrospector>();

     private final Version incompatibleImprovements;

     // Properties and their *defaults*:
     private int exposureLevel = BeansWrapper.EXPOSE_SAFE;
     private boolean exposeFields;
     private MemberAccessPolicy memberAccessPolicy;
     private boolean treatDefaultMethodsAsBeanMembers;
     private MethodAppearanceFineTuner methodAppearanceFineTuner;
     private MethodSorter methodSorter;
     // Attention:
     // - This is also used as a cache key, so non-normalized field values should be avoided.
     // - If some field has a default value, it must be set until the end of the constructor. No field that has a
     //   default can be left unset (like null).
     // - If you add a new field, review all methods in this class, also the ClassIntrospector constructor

     ClassIntrospectorBuilder(ClassIntrospector ci) {
         incompatibleImprovements = ci.incompatibleImprovements;
         exposureLevel = ci.exposureLevel;
         exposeFields = ci.exposeFields;
         memberAccessPolicy = ci.memberAccessPolicy;
         treatDefaultMethodsAsBeanMembers = ci.treatDefaultMethodsAsBeanMembers;
         methodAppearanceFineTuner = ci.methodAppearanceFineTuner;
         methodSorter = ci.methodSorter;
     }

     ClassIntrospectorBuilder(Version incompatibleImprovements) {
         // Warning: incompatibleImprovements must not affect this object at versions increments where there's no
         // change in the BeansWrapper.normalizeIncompatibleImprovements results. That is, this class may don't react
         // to some version changes that affects BeansWrapper, but not the other way around.
         this.incompatibleImprovements = normalizeIncompatibleImprovementsVersion(incompatibleImprovements);
         treatDefaultMethodsAsBeanMembers
                 = incompatibleImprovements.intValue() >= _TemplateAPI.VERSION_INT_2_3_26;
         memberAccessPolicy = DefaultMemberAccessPolicy.getInstance(this.incompatibleImprovements);
     }

     private static Version normalizeIncompatibleImprovementsVersion(Version incompatibleImprovements) {
         _TemplateAPI.checkVersionNotNullAndSupported(incompatibleImprovements);
         // All breakpoints here must occur in BeansWrapper.normalizeIncompatibleImprovements!
         return incompatibleImprovements.intValue() >= _TemplateAPI.VERSION_INT_2_3_30 ? Configuration.VERSION_2_3_30
                 : incompatibleImprovements.intValue() >= _TemplateAPI.VERSION_INT_2_3_21 ? Configuration.VERSION_2_3_21
                 : Configuration.VERSION_2_3_0;
     }

     @Override
     protected Object clone() {
         try {
             return super.clone();
         } catch (CloneNotSupportedException e) {
             throw new RuntimeException("Failed to clone ClassIntrospectorBuilder", e);
         }
     }

     @Override
     public int hashCode() {
         final int prime = 31;
         int result = 1;
         result = prime * result + incompatibleImprovements.hashCode();
         result = prime * result + (exposeFields ? 1231 : 1237);
         result = prime * result + (treatDefaultMethodsAsBeanMembers ? 1231 : 1237);
         result = prime * result + exposureLevel;
         result = prime * result + memberAccessPolicy.hashCode();
         result = prime * result + System.identityHashCode(methodAppearanceFineTuner);
         result = prime * result + System.identityHashCode(methodSorter);
         return result;
     }

     @Override
     public boolean equals(Object obj) {
         if (this == obj) return true;
         if (obj == null) return false;
         if (getClass() != obj.getClass()) return false;
         ClassIntrospectorBuilder other = (ClassIntrospectorBuilder) obj;

         if (!incompatibleImprovements.equals(other.incompatibleImprovements)) return false;
         if (exposeFields != other.exposeFields) return false;
         if (treatDefaultMethodsAsBeanMembers != other.treatDefaultMethodsAsBeanMembers) return false;
         if (exposureLevel != other.exposureLevel) return false;
         if (!memberAccessPolicy.equals(other.memberAccessPolicy)) return false;
         if (methodAppearanceFineTuner != other.methodAppearanceFineTuner) return false;
         if (methodSorter != other.methodSorter) return false;

         return true;
     }

     public int getExposureLevel() {
         return exposureLevel;
     }

     /** See {@link BeansWrapper#setExposureLevel(int)}. */
     public void setExposureLevel(int exposureLevel) {
         if (exposureLevel < BeansWrapper.EXPOSE_ALL || exposureLevel > BeansWrapper.EXPOSE_NOTHING) {
             throw new IllegalArgumentException("Illegal exposure level: " + exposureLevel);
         }

         this.exposureLevel = exposureLevel;
     }

     public boolean getExposeFields() {
         return exposeFields;
     }

     /** See {@link BeansWrapper#setExposeFields(boolean)}. */
     public void setExposeFields(boolean exposeFields) {
         this.exposeFields = exposeFields;
     }

     public boolean getTreatDefaultMethodsAsBeanMembers() {
         return treatDefaultMethodsAsBeanMembers;
     }

     public void setTreatDefaultMethodsAsBeanMembers(boolean treatDefaultMethodsAsBeanMembers) {
         this.treatDefaultMethodsAsBeanMembers = treatDefaultMethodsAsBeanMembers;
     }

     public MemberAccessPolicy getMemberAccessPolicy() {
         return memberAccessPolicy;
     }

     public void setMemberAccessPolicy(MemberAccessPolicy memberAccessPolicy) {
         NullArgumentException.check(memberAccessPolicy);
         this.memberAccessPolicy = memberAccessPolicy;
     }

     public MethodAppearanceFineTuner getMethodAppearanceFineTuner() {
         return methodAppearanceFineTuner;
     }

     public void setMethodAppearanceFineTuner(MethodAppearanceFineTuner methodAppearanceFineTuner) {
         this.methodAppearanceFineTuner = methodAppearanceFineTuner;
     }

     public MethodSorter getMethodSorter() {
         return methodSorter;
     }

     public void setMethodSorter(MethodSorter methodSorter) {
         this.methodSorter = methodSorter;
     }

     /**
      * Returns the normalized incompatible improvements.
      */
     public Version getIncompatibleImprovements() {
         return incompatibleImprovements;
     }

     private static void removeClearedReferencesFromInstanceCache() {
         Reference<? extends ClassIntrospector> clearedRef;
         while ((clearedRef = INSTANCE_CACHE_REF_QUEUE.poll()) != null) {
             synchronized (INSTANCE_CACHE) {
                 findClearedRef: for (Iterator<Reference<ClassIntrospector>> it = INSTANCE_CACHE.values().iterator();
                          it.hasNext(); ) {
                     if (it.next() == clearedRef) {
                         it.remove();
                         break findClearedRef;
                     }
                 }
             }
         }
     }

     /** For unit testing only */
     static void clearInstanceCache() {
         synchronized (INSTANCE_CACHE) {
             INSTANCE_CACHE.clear();
         }
     }

     /** For unit testing only */
     static Map<ClassIntrospectorBuilder, Reference<ClassIntrospector>> getInstanceCache() {
         return INSTANCE_CACHE;
     }

     /**
      * Returns an instance that is possibly shared (singleton). Note that this comes with its own "shared lock",
      * since everyone who uses this object will have to lock with that common object.
      */
     ClassIntrospector build() {
         if ((methodAppearanceFineTuner == null || methodAppearanceFineTuner instanceof SingletonCustomizer)
                 && (methodSorter == null || methodSorter instanceof SingletonCustomizer)) {
             // Instance can be cached.
             ClassIntrospector instance;
             synchronized (INSTANCE_CACHE) {
                 Reference<ClassIntrospector> instanceRef = INSTANCE_CACHE.get(this);
                 instance = instanceRef != null ? instanceRef.get() : null;
                 if (instance == null) {
                     ClassIntrospectorBuilder thisClone = (ClassIntrospectorBuilder) clone();  // prevent any aliasing issues
                     instance = new ClassIntrospector(thisClone, new Object(), true, true);
                     INSTANCE_CACHE.put(thisClone, new WeakReference<ClassIntrospector>(instance, INSTANCE_CACHE_REF_QUEUE));
                 }
             }

             removeClearedReferencesFromInstanceCache();

             return instance;
         } else {
             // If methodAppearanceFineTuner or methodSorter is specified and isn't marked as a singleton, the
             // ClassIntrospector can't be shared/cached as those objects could contain a back-reference to the
             // BeansWrapper.
             return new ClassIntrospector(this, new Object(), true, false);
         }
     }

 }
	/*
	* 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 freemarker.ext.beans;

	import java.lang.ref.Reference;
	import java.lang.ref.ReferenceQueue;
	import java.lang.ref.WeakReference;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.Map;

	import freemarker.template.Configuration;
	import freemarker.template.Version;
	import freemarker.template._TemplateAPI;
	import freemarker.template.utility.NullArgumentException;

	final class ClassIntrospectorBuilder implements Cloneable {

	private static final Map<ClassIntrospectorBuilder, Reference<ClassIntrospector>> INSTANCE_CACHE
	= new HashMap<ClassIntrospectorBuilder, Reference<ClassIntrospector>>();
	private static final ReferenceQueue<ClassIntrospector> INSTANCE_CACHE_REF_QUEUE
	= new ReferenceQueue<ClassIntrospector>();

	private final Version incompatibleImprovements;

	// Properties and their defaults:
	private int exposureLevel = BeansWrapper.EXPOSE_SAFE;
	private boolean exposeFields;
	private MemberAccessPolicy memberAccessPolicy;
	private boolean treatDefaultMethodsAsBeanMembers;
	private MethodAppearanceFineTuner methodAppearanceFineTuner;
	private MethodSorter methodSorter;
	// Attention:
	// - This is also used as a cache key, so non-normalized field values should be avoided.
	// - If some field has a default value, it must be set until the end of the constructor. No field that has a
	// default can be left unset (like null).
	// - If you add a new field, review all methods in this class, also the ClassIntrospector constructor

	ClassIntrospectorBuilder(ClassIntrospector ci) {
	incompatibleImprovements = ci.incompatibleImprovements;
	exposureLevel = ci.exposureLevel;
	exposeFields = ci.exposeFields;
	memberAccessPolicy = ci.memberAccessPolicy;
	treatDefaultMethodsAsBeanMembers = ci.treatDefaultMethodsAsBeanMembers;
	methodAppearanceFineTuner = ci.methodAppearanceFineTuner;
	methodSorter = ci.methodSorter;
	}

	ClassIntrospectorBuilder(Version incompatibleImprovements) {
	// Warning: incompatibleImprovements must not affect this object at versions increments where there's no
	// change in the BeansWrapper.normalizeIncompatibleImprovements results. That is, this class may don't react
	// to some version changes that affects BeansWrapper, but not the other way around.
	this.incompatibleImprovements = normalizeIncompatibleImprovementsVersion(incompatibleImprovements);
	treatDefaultMethodsAsBeanMembers
	= incompatibleImprovements.intValue() >= _TemplateAPI.VERSION_INT_2_3_26;
	memberAccessPolicy = DefaultMemberAccessPolicy.getInstance(this.incompatibleImprovements);
	}

	private static Version normalizeIncompatibleImprovementsVersion(Version incompatibleImprovements) {
	_TemplateAPI.checkVersionNotNullAndSupported(incompatibleImprovements);
	// All breakpoints here must occur in BeansWrapper.normalizeIncompatibleImprovements!
	return incompatibleImprovements.intValue() >= _TemplateAPI.VERSION_INT_2_3_30 ? Configuration.VERSION_2_3_30
	: incompatibleImprovements.intValue() >= _TemplateAPI.VERSION_INT_2_3_21 ? Configuration.VERSION_2_3_21
	: Configuration.VERSION_2_3_0;
	}

	@Override
	protected Object clone() {
	try {
	return super.clone();
	} catch (CloneNotSupportedException e) {
	throw new RuntimeException("Failed to clone ClassIntrospectorBuilder", e);
	}
	}

	@Override
	public int hashCode() {
	final int prime = 31;
	int result = 1;
	result = prime * result + incompatibleImprovements.hashCode();
	result = prime * result + (exposeFields ? 1231 : 1237);
	result = prime * result + (treatDefaultMethodsAsBeanMembers ? 1231 : 1237);
	result = prime * result + exposureLevel;
	result = prime * result + memberAccessPolicy.hashCode();
	result = prime * result + System.identityHashCode(methodAppearanceFineTuner);
	result = prime * result + System.identityHashCode(methodSorter);
	return result;
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj) return true;
	if (obj == null) return false;
	if (getClass() != obj.getClass()) return false;
	ClassIntrospectorBuilder other = (ClassIntrospectorBuilder) obj;

	if (!incompatibleImprovements.equals(other.incompatibleImprovements)) return false;
	if (exposeFields != other.exposeFields) return false;
	if (treatDefaultMethodsAsBeanMembers != other.treatDefaultMethodsAsBeanMembers) return false;
	if (exposureLevel != other.exposureLevel) return false;
	if (!memberAccessPolicy.equals(other.memberAccessPolicy)) return false;
	if (methodAppearanceFineTuner != other.methodAppearanceFineTuner) return false;
	if (methodSorter != other.methodSorter) return false;

	return true;
	}

	public int getExposureLevel() {
	return exposureLevel;
	}

	/** See {@link BeansWrapper#setExposureLevel(int)}. */
	public void setExposureLevel(int exposureLevel) {
	if (exposureLevel < BeansWrapper.EXPOSE_ALL \|\| exposureLevel > BeansWrapper.EXPOSE_NOTHING) {
	throw new IllegalArgumentException("Illegal exposure level: " + exposureLevel);
	}

	this.exposureLevel = exposureLevel;
	}

	public boolean getExposeFields() {
	return exposeFields;
	}

	/** See {@link BeansWrapper#setExposeFields(boolean)}. */
	public void setExposeFields(boolean exposeFields) {
	this.exposeFields = exposeFields;
	}

	public boolean getTreatDefaultMethodsAsBeanMembers() {
	return treatDefaultMethodsAsBeanMembers;
	}

	public void setTreatDefaultMethodsAsBeanMembers(boolean treatDefaultMethodsAsBeanMembers) {
	this.treatDefaultMethodsAsBeanMembers = treatDefaultMethodsAsBeanMembers;
	}

	public MemberAccessPolicy getMemberAccessPolicy() {
	return memberAccessPolicy;
	}

	public void setMemberAccessPolicy(MemberAccessPolicy memberAccessPolicy) {
	NullArgumentException.check(memberAccessPolicy);
	this.memberAccessPolicy = memberAccessPolicy;
	}

	public MethodAppearanceFineTuner getMethodAppearanceFineTuner() {
	return methodAppearanceFineTuner;
	}

	public void setMethodAppearanceFineTuner(MethodAppearanceFineTuner methodAppearanceFineTuner) {
	this.methodAppearanceFineTuner = methodAppearanceFineTuner;
	}

	public MethodSorter getMethodSorter() {
	return methodSorter;
	}

	public void setMethodSorter(MethodSorter methodSorter) {
	this.methodSorter = methodSorter;
	}

	/**
	* Returns the normalized incompatible improvements.
	*/
	public Version getIncompatibleImprovements() {
	return incompatibleImprovements;
	}

	private static void removeClearedReferencesFromInstanceCache() {
	Reference<? extends ClassIntrospector> clearedRef;
	while ((clearedRef = INSTANCE_CACHE_REF_QUEUE.poll()) != null) {
	synchronized (INSTANCE_CACHE) {
	findClearedRef: for (Iterator<Reference<ClassIntrospector>> it = INSTANCE_CACHE.values().iterator();
	it.hasNext(); ) {
	if (it.next() == clearedRef) {
	it.remove();
	break findClearedRef;
	}
	}
	}
	}
	}

	/** For unit testing only */
	static void clearInstanceCache() {
	synchronized (INSTANCE_CACHE) {
	INSTANCE_CACHE.clear();
	}
	}

	/** For unit testing only */
	static Map<ClassIntrospectorBuilder, Reference<ClassIntrospector>> getInstanceCache() {
	return INSTANCE_CACHE;
	}

	/**
	* Returns an instance that is possibly shared (singleton). Note that this comes with its own "shared lock",
	* since everyone who uses this object will have to lock with that common object.
	*/
	ClassIntrospector build() {
	if ((methodAppearanceFineTuner == null \|\| methodAppearanceFineTuner instanceof SingletonCustomizer)
	&& (methodSorter == null \|\| methodSorter instanceof SingletonCustomizer)) {
	// Instance can be cached.
	ClassIntrospector instance;
	synchronized (INSTANCE_CACHE) {
	Reference<ClassIntrospector> instanceRef = INSTANCE_CACHE.get(this);
	instance = instanceRef != null ? instanceRef.get() : null;
	if (instance == null) {
	ClassIntrospectorBuilder thisClone = (ClassIntrospectorBuilder) clone(); // prevent any aliasing issues
	instance = new ClassIntrospector(thisClone, new Object(), true, true);
	INSTANCE_CACHE.put(thisClone, new WeakReference<ClassIntrospector>(instance, INSTANCE_CACHE_REF_QUEUE));
	}
	}

	removeClearedReferencesFromInstanceCache();

	return instance;
	} else {
	// If methodAppearanceFineTuner or methodSorter is specified and isn't marked as a singleton, the
	// ClassIntrospector can't be shared/cached as those objects could contain a back-reference to the
	// BeansWrapper.
	return new ClassIntrospector(this, new Object(), true, false);
	}
	}

	}