dagger.internal.codegen.writer.TypeVariableName.java Source code

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Here is the source code for dagger.internal.codegen.writer.TypeVariableName.java

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/*
 * Copyright (C) 2014 Google, Inc.
 *
 * Licensed 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 dagger.internal.codegen.writer;

import com.google.auto.common.MoreTypes;
import com.google.common.base.Objects;
import com.google.common.base.Predicate;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import java.io.IOException;
import java.util.Iterator;
import java.util.Set;
import javax.lang.model.element.TypeParameterElement;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.type.TypeVariable;

public final class TypeVariableName implements TypeName {
    private final CharSequence name;
    private final Iterable<? extends TypeName> extendsBounds;

    TypeVariableName(CharSequence name, Iterable<? extends TypeName> extendsBounds) {
        this.name = name;
        this.extendsBounds = extendsBounds;
    }

    public CharSequence name() {
        return name;
    }

    @Override
    public Set<ClassName> referencedClasses() {
        ImmutableSet.Builder<ClassName> builder = new ImmutableSet.Builder<ClassName>();
        for (TypeName bound : extendsBounds) {
            builder.addAll(bound.referencedClasses());
        }
        return builder.build();
    }

    @Override
    public Appendable write(Appendable appendable, Context context) throws IOException {
        appendable.append(name);
        if (!Iterables.isEmpty(extendsBounds)) {
            appendable.append(" extends ");
            Iterator<? extends TypeName> iter = extendsBounds.iterator();
            iter.next().write(appendable, context);
            while (iter.hasNext()) {
                appendable.append(" & ");
                iter.next().write(appendable, context);
            }
        }
        return appendable;
    }

    @Override
    public String toString() {
        return Writables.writeToString(this);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof TypeVariableName) {
            TypeVariableName that = (TypeVariableName) obj;
            return this.name.toString().equals(that.name.toString())
                    && this.extendsBounds.equals(that.extendsBounds);
        } else {
            return false;
        }
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(name, extendsBounds);
    }

    static TypeVariableName named(CharSequence name) {
        return new TypeVariableName(name, ImmutableList.<TypeName>of());
    }

    public static TypeVariableName fromTypeVariable(TypeVariable variable) {
        // Note: We don't have any use right now for the bounds because these are references
        // to the type & not the specification of the type itself.  We never generate
        // code with type variables that include upper or lower bounds.
        return named(variable.asElement().getSimpleName());
    }

    // TODO(sameb): Consider making this a whole different thing: TypeParameterName since it
    // has different semantics than a TypeVariable (parameters only have upper bounds).
    public static TypeVariableName fromTypeParameterElement(TypeParameterElement element) {
        // We filter out bounds of type Object because those would just clutter the generated code.
        Iterable<? extends TypeName> bounds = FluentIterable.from(element.getBounds())
                .filter(new Predicate<TypeMirror>() {
                    @Override
                    public boolean apply(TypeMirror input) {
                        return !MoreTypes.isType(input) || !MoreTypes.isTypeOf(Object.class, input);
                    }
                }).transform(TypeNames.FOR_TYPE_MIRROR);
        return new TypeVariableName(element.getSimpleName(), bounds);
    }
}