Mailing-List: contact dev-help@brooklyn.incubator.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@brooklyn.incubator.apache.org
From: neykov <git@git.apache.org>
To: dev@brooklyn.incubator.apache.org
Reply-To: dev@brooklyn.incubator.apache.org
References: <git-pr-1017-incubator-brooklyn@git.apache.org>
In-Reply-To: <git-pr-1017-incubator-brooklyn@git.apache.org>
Subject: [GitHub] incubator-brooklyn pull request: Flesh out type creation
 using the...
Content-Type: text/plain
Message-Id: <20151112102142.270C8E5DFE@git1-us-west.apache.org>
Date: Thu, 12 Nov 2015 10:21:42 +0000 (UTC)

Github user neykov commented on a diff in the pull request:

    https://github.com/apache/incubator-brooklyn/pull/1017#discussion_r44640885
  
    --- Diff: core/src/main/java/org/apache/brooklyn/core/typereg/RegisteredTypeLoadingContexts.java ---
    @@ -0,0 +1,236 @@
    +/*
    + * 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.brooklyn.core.typereg;
    +
    +import groovy.xml.Entity;
    +
    +import java.util.Set;
    +
    +import javax.annotation.Nonnull;
    +import javax.annotation.Nullable;
    +
    +import org.apache.brooklyn.api.entity.EntitySpec;
    +import org.apache.brooklyn.api.internal.AbstractBrooklynObjectSpec;
    +import org.apache.brooklyn.api.mgmt.classloading.BrooklynClassLoadingContext;
    +import org.apache.brooklyn.api.objs.BrooklynObject;
    +import org.apache.brooklyn.api.objs.BrooklynObjectType;
    +import org.apache.brooklyn.api.typereg.BrooklynTypeRegistry.RegisteredTypeKind;
    +import org.apache.brooklyn.api.typereg.RegisteredTypeLoadingContext;
    +import org.apache.brooklyn.util.collections.MutableSet;
    +import org.apache.brooklyn.util.javalang.JavaClassNames;
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import com.google.common.collect.ImmutableSet;
    +
    +public class RegisteredTypeLoadingContexts {
    +
    +    private static final Logger log = LoggerFactory.getLogger(RegisteredTypeLoadingContexts.BasicRegisteredTypeLoadingContext.class);
    +    
    +    /** Immutable (from caller's perspective) record of a constraint */
    +    public final static class BasicRegisteredTypeLoadingContext implements RegisteredTypeLoadingContext {
    +        @Nullable private RegisteredTypeKind kind;
    +        @Nullable private Class<?> expectedSuperType;
    +        @Nonnull private Set<String> encounteredTypes = ImmutableSet.of();
    +        @Nullable BrooklynClassLoadingContext loader;
    +        
    +        private BasicRegisteredTypeLoadingContext() {}
    +        
    +        public BasicRegisteredTypeLoadingContext(@Nullable RegisteredTypeLoadingContext source) {
    +            if (source==null) return;
    +            
    +            this.kind = source.getExpectedKind();
    +            this.expectedSuperType = source.getExpectedJavaSuperType();
    +            this.encounteredTypes = source.getAlreadyEncounteredTypes();
    +            this.loader = (BrooklynClassLoadingContext) source.getLoader();
    +        }
    +
    +        @Override
    +        public RegisteredTypeKind getExpectedKind() {
    +            return kind;
    +        }
    +        
    +        @Override
    +        public Class<?> getExpectedJavaSuperType() {
    +            if (expectedSuperType==null) return Object.class;
    +            return expectedSuperType;
    +        }
    +
    +        @Override
    +        public Set<String> getAlreadyEncounteredTypes() {
    +            if (encounteredTypes==null) return ImmutableSet.of();
    +            return ImmutableSet.<String>copyOf(encounteredTypes);
    +        }
    +        
    +        @Override
    +        public BrooklynClassLoadingContext getLoader() {
    +            return loader;
    +        }
    +        
    +        @Override
    +        public String toString() {
    +            return JavaClassNames.cleanSimpleClassName(this)+"["+kind+","+expectedSuperType+","+encounteredTypes+"]";
    +        }
    +    }
    +
    +    /** returns a constraint which allows anything */
    +    public static RegisteredTypeLoadingContext any() {
    +        return new BasicRegisteredTypeLoadingContext();
    +    }
    +
    +    public static RegisteredTypeLoadingContext alreadyEncountered(Set<String> encounteredTypeSymbolicNames) {
    +        BasicRegisteredTypeLoadingContext result = new BasicRegisteredTypeLoadingContext();
    +        result.encounteredTypes = encounteredTypeSymbolicNames == null ? ImmutableSet.<String>of() : ImmutableSet.copyOf(encounteredTypeSymbolicNames);
    +        return result;
    +    }
    +    public static RegisteredTypeLoadingContext alreadyEncountered(Set<String> encounteredTypeSymbolicNames, String anotherEncounteredType) {
    +        BasicRegisteredTypeLoadingContext result = new BasicRegisteredTypeLoadingContext();
    +        MutableSet<String> encounteredTypes = MutableSet.copyOf(encounteredTypeSymbolicNames);
    +        encounteredTypes.addIfNotNull(anotherEncounteredType);
    +        result.encounteredTypes = encounteredTypes.asUnmodifiable();
    +        return result;
    +    }
    +
    +    public static RegisteredTypeLoadingContext loaderAlreadyEncountered(BrooklynClassLoadingContext loader, Set<String> encounteredTypeSymbolicNames) {
    +        return loaderAlreadyEncountered(loader, encounteredTypeSymbolicNames, null);
    +    }
    +    public static RegisteredTypeLoadingContext loaderAlreadyEncountered(BrooklynClassLoadingContext loader, Set<String> encounteredTypeSymbolicNames, String anotherEncounteredType) {
    +        return withLoader(alreadyEncountered(encounteredTypeSymbolicNames, anotherEncounteredType), loader);
    +    }
    +
    +    private static RegisteredTypeLoadingContext of(RegisteredTypeKind kind, Class<?> javaSuperType) {
    +        BasicRegisteredTypeLoadingContext result = new BasicRegisteredTypeLoadingContext();
    +        result.kind = kind;
    +        result.expectedSuperType = javaSuperType;
    +        return result;
    +    }
    +
    +    public static RegisteredTypeLoadingContext bean(Class<?> javaSuperType) {
    +        return of(RegisteredTypeKind.BEAN, javaSuperType);
    +    }
    +
    +    public static RegisteredTypeLoadingContext spec(Class<? extends BrooklynObject> javaSuperType) {
    +        return of(RegisteredTypeKind.SPEC, javaSuperType);
    +    }
    +    
    +    public static <T> RegisteredTypeLoadingContext withBeanSuperType(@Nullable RegisteredTypeLoadingContext source, @Nullable Class<T> beanSuperType) {
    +        Class<T> superType = beanSuperType;
    +        BasicRegisteredTypeLoadingContext constraint = new BasicRegisteredTypeLoadingContext(source);
    +        if (source==null) source = constraint;
    +        if (superType==null) return source;
    +        constraint.expectedSuperType = superType;
    +        if (source.getExpectedJavaSuperType()==null || source.getExpectedJavaSuperType().isAssignableFrom( superType )) {
    +            // the old constraint was weaker than present; return the new constraint
    +            return constraint;
    +        }
    +        if (superType.isAssignableFrom( source.getExpectedJavaSuperType() )) {
    +            // the constraint was already for something more specific; ignore what we've inferred here
    +            return source;
    +        }
    +        log.warn("Ambiguous bean supertypes ("+beanSuperType+" for target "+source.getExpectedJavaSuperType()+"); "
    +            + "it is recommended that any registered type constraint for a spec be compatible with the spec type");
    +        return source;
    +    }
    +
    +    /** Takes a Spec java type and adds an expected java type to the {@link RegisteredTypeLoadingContext} */
    +    public static <T extends AbstractBrooklynObjectSpec<?,?>> RegisteredTypeLoadingContext withSpecSuperType(@Nullable RegisteredTypeLoadingContext source, @Nullable Class<T> specSuperType) {
    +        Class<?> superType = lookupTargetTypeForSpec(specSuperType);
    +        BasicRegisteredTypeLoadingContext constraint = new BasicRegisteredTypeLoadingContext(source);
    +        if (source==null) source = constraint;
    +        if (superType==null) return source;
    +        constraint.expectedSuperType = superType;
    +        if (source.getExpectedJavaSuperType()==null || source.getExpectedJavaSuperType().isAssignableFrom( superType )) {
    +            // the old constraint was weaker than present; return the new constraint
    +            return constraint;
    +        }
    +        if (superType.isAssignableFrom( source.getExpectedJavaSuperType() )) {
    +            // the constraint was already for something more specific; ignore what we've inferred here
    +            return source;
    +        }
    +        // trickier situation; the constraint had a type not compatible with the spec type; log a warning and leave alone
    +        // (e.g. caller specified some java super type which is not a super or sub of the spec target type;
    +        // this may be because the caller specified a Spec as the type supertype, which is wrong;
    +        // or they may have specified an interface along a different hierarchy, which we discouraged
    +        // as it will make filtering/indexing more complex)
    +        log.warn("Ambiguous spec supertypes ("+specSuperType+" for target "+source.getExpectedJavaSuperType()+"); "
    +            + "it is recommended that any registered type constraint for a spec be compatible with the spec type");
    +        return source;
    +    }
    +        
    +    /** given a spec, returns the class of the item it targets, for instance returns {@link Entity} given {@link EntitySpec};
    +     * see also {@link #lookupSpecTypeForTarget(Class)} */
    +    static <T extends AbstractBrooklynObjectSpec<?,?>> Class<? extends BrooklynObject> lookupTargetTypeForSpec(Class<T> specSuperType) {
    +        if (specSuperType==null) return BrooklynObject.class;
    +        BrooklynObjectType best = null;
    +
    +        for (BrooklynObjectType t: BrooklynObjectType.values()) {
    +            if (t.getSpecType()==null) continue;
    +            if (!t.getSpecType().isAssignableFrom(specSuperType)) continue;
    +            // on equality, exit immediately
    +            if (t.getSpecType().equals(specSuperType)) return t.getInterfaceType();
    +            // else pick which is best
    +            if (best==null) { best = t; continue; }
    +            // if t is more specific, it is better (handles case when e.g. a Policy is a subclass of Entity)
    +            if (best.getSpecType().isAssignableFrom(t.getSpecType())) { best = t; continue; }
    +        }
    +        if (best==null) {
    +            log.warn("Unexpected spec supertype ("+specSuperType+"); treating as any "+BrooklynObject.class, new Throwable("Trace for unexpected spec supertype"));
    +            return BrooklynObject.class;
    +        }
    +        // the spec is more specific, but we're not familiar with it here; return the best
    +        return best.getInterfaceType();
    +    }
    +
    +    /** given a {@link BrooklynObject}, returns the spec class which would generate it, for instance returns {@link EntitySpec} given {@link Entity},
    +     * or null if not known */
    +    static <BO extends BrooklynObject> Class<? extends AbstractBrooklynObjectSpec<?,?>> lookupSpecTypeForTarget(Class<BO> targetSuperType) {
    +        if (targetSuperType==null) return null;
    +        BrooklynObjectType best = null;
    +
    +        for (BrooklynObjectType t: BrooklynObjectType.values()) {
    +            if (t.getSpecType()==null) continue;
    +            if (!t.getInterfaceType().isAssignableFrom(targetSuperType)) continue;
    +            // on equality, exit immediately
    +            if (t.getInterfaceType().equals(targetSuperType)) return t.getSpecType();
    +            // else pick which is best
    +            if (best==null) { best = t; continue; }
    +            // if t is more specific, it is better (handles case when e.g. a Policy is a subclass of Entity)
    +            if (best.getSpecType().isAssignableFrom(t.getSpecType())) { best = t; continue; }
    --- End diff --
    
    Again should be `getInterfaceType()`


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---