com.google.inject.assistedinject.AssistedConstructor Maven / Gradle / Ivy

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package com.google.inject.assistedinject;

import com.google.common.collect.Lists;
import com.google.inject.Inject;
import com.google.inject.TypeLiteral;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * Internal respresentation of a constructor annotated with
 * {@link AssistedInject}
 */
class AssistedConstructor {

    private final Constructor constructor;
    private final ParameterListKey assistedParameters;
    private final List allParameters;

    private AssistedConstructor(Constructor constructor, List> parameterTypes) {
        this.constructor = constructor;

        Annotation[][] annotations = constructor.getParameterAnnotations();

        List typeList = Lists.newArrayList();
        allParameters = new ArrayList();

        // categorize params as @Assisted or @Injected
        for (int i = 0; i < parameterTypes.size(); i++) {
            Parameter parameter = new Parameter(parameterTypes.get(i).getType(), annotations[i]);
            allParameters.add(parameter);
            if (parameter.isProvidedByFactory()) {
                typeList.add(parameter.getType());
            }
        }
        this.assistedParameters = new ParameterListKey(typeList);
    }

    public static  AssistedConstructor create(
            Constructor constructor, List> parameterTypes) {
        return new AssistedConstructor(constructor, parameterTypes);
    }

    /**
     * Returns the {@link ParameterListKey} for this constructor.  The
     * {@link ParameterListKey} is created from the ordered list of {@link Assisted}
     * constructor parameters.
     */
    public ParameterListKey getAssistedParameters() {
        return assistedParameters;
    }

    /**
     * Returns an ordered list of all constructor parameters (both
     * {@link Assisted} and {@link Inject}ed).
     */
    public List getAllParameters() {
        return allParameters;
    }

    public Set> getDeclaredExceptions() {
        return new HashSet>(Arrays.asList(constructor.getExceptionTypes()));
    }

    /**
     * Returns an instance of T, constructed using this constructor, with the
     * supplied arguments.
     */
    public T newInstance(Object[] args) throws Throwable {
        constructor.setAccessible(true);
        try {
            return constructor.newInstance(args);
        } catch (InvocationTargetException e) {
            throw e.getCause();
        }
    }

    @Override
    public String toString() {
        return constructor.toString();
    }
}