guice/src/main/java/com/google/inject/internal/ExposureBuilder.java

package com.google.inject.internal;

import com.google.common.base.Preconditions;
import com.google.inject.Binder;
import com.google.inject.Key;
import com.google.inject.binder.AnnotatedElementBuilder;

import java.lang.annotation.Annotation;

/**
 * For private binder's expose() method.
 */
public class ExposureBuilder<T> implements AnnotatedElementBuilder {
    private final Binder binder;
    private final Object source;
    private Key<T> key;

    public ExposureBuilder(Binder binder, Object source, Key<T> key) {
        this.binder = binder;
        this.source = source;
        this.key = key;
    }

    protected void checkNotAnnotated() {
        if (key.getAnnotationType() != null) {
            binder.addError(AbstractBindingBuilder.ANNOTATION_ALREADY_SPECIFIED);
        }
    }

    @Override
    public void annotatedWith(Class<? extends Annotation> annotationType) {
        Preconditions.checkNotNull(annotationType, "annotationType");
        checkNotAnnotated();
        key = Key.get(key.getTypeLiteral(), annotationType);
    }

    @Override
    public void annotatedWith(Annotation annotation) {
        Preconditions.checkNotNull(annotation, "annotation");
        checkNotAnnotated();
        key = Key.get(key.getTypeLiteral(), annotation);
    }

    public Key<?> getKey() {
        return key;
    }

    public Object getSource() {
        return source;
    }

    @Override
    public String toString() {
        return "AnnotatedElementBuilder";
    }
}