platform/sensinact-common/src/main/java/org/eclipse/sensinact/gateway/common/constraint/ConstraintOnCollection.java

/*
* Copyright (c) 2020 Kentyou.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
*    Kentyou - initial API and implementation
 */
package org.eclipse.sensinact.gateway.common.constraint;

import org.eclipse.sensinact.gateway.util.CastUtils;
import org.eclipse.sensinact.gateway.util.JSONUtils;

import java.lang.reflect.Array;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.logging.Logger;

/**
 * Constraint applying on set of data
 *
 * @param <T> the type of the handled data set
 * @author <a href="mailto:christophe.munilla@cea.fr">Christophe Munilla</a>
 */
public abstract class ConstraintOnCollection<T> implements Constraint {
    protected static final Logger LOGGER = Logger.getLogger(ConstraintOnCollection.class.getCanonicalName());

    /**
     * String operator of this Constraint
     */
    protected final String operator;
    /**
     * Defines whether this constraint is the
     * logical complement of the raw defined constraint
     */
    protected final boolean complement;

    /**
     * Operand on which to base the constraint compliance evaluation
     */
    protected final T[] operand;
    /**
     * Operand array component type
     */
    protected Class<T> operandClass;
    /**
     * Mediator used to interact with the OSGi host
     * environment
     */
    protected final ClassLoader classloader;

    /**
     * @param operator
     * @param operand
     * @throws InvalidConstraintDefinitionException
     */
    public ConstraintOnCollection(ClassLoader classloader, String operator, T[] operand, boolean complement) throws InvalidConstraintDefinitionException {
        this.classloader = classloader;
        this.operator = operator;
        if (operand == null) {
            throw new InvalidConstraintDefinitionException("operand argument is required");
        }
        this.operand = operand;
        this.operandClass = (Class<T>) this.operand.getClass().getComponentType();
        this.complement = complement;
    }

    /**
     * Constructor
     *
     * @param operator     String operator of this constraint
     * @param operandClass use the Enum class if the constraint applies on its constants
     *                     set use the component type or the array class if the
     *                     constraint applies on an array or a collection
     * @param operand      use null if this constraint applies on the constants set of an
     *                     Enum class use the array or collection object if the
     *                     constraint applies on it
     * @throws InvalidConstraintDefinitionException
     */
    @SuppressWarnings("unchecked")
    public ConstraintOnCollection(ClassLoader classloader, String operator, Class<T> operandClass, Object operand, boolean complement) throws InvalidConstraintDefinitionException {
        if (operandClass == null) {
            throw new InvalidConstraintDefinitionException("type is required");
        }
        this.classloader = classloader;
        this.operator = operator;
        this.complement = complement;

        if (operand == null) {
            if (operandClass.isEnum()) {
                this.operandClass = operandClass;
                this.operand = (T[]) ((Class<? extends Enum<?>>) operandClass).getEnumConstants();
                return;
            }
            throw new InvalidConstraintDefinitionException("If the operand argument is null the type " + "must be an Enum one");
        }
        if (operandClass.isArray()) {
            this.operandClass = (Class<T>) operandClass.getComponentType();
        } else if (Collection.class.isAssignableFrom(operandClass)) {
            Type[] interfaces = operandClass.getGenericInterfaces();
            Class<?> generic = null;
            for (Type genericInterface : interfaces) {
                try {
                    ParameterizedType parameterized = (ParameterizedType) genericInterface;
                    if (Collection.class.isAssignableFrom(((Class<?>) parameterized.getRawType()))) {
                        generic = (Class<T>) parameterized.getActualTypeArguments()[0];
                        break;
                    }
                } catch (ClassCastException e) {
                    continue;
                }
            }
            if (generic == null) {
                throw new InvalidConstraintDefinitionException("Unable to retrieve the type from the specified extended Collection one");
            }
            this.operandClass = (Class<T>) generic;
        } else {
            this.operandClass = operandClass;
        }
        Class<T> castedOperandClass = (Class<T>) CastUtils.primitiveToComparable(this.operandClass);
        this.operandClass = castedOperandClass != null ? castedOperandClass : this.operandClass;
        try {
            this.operand = (T[]) CastUtils.castArray(this.classloader, ((T[]) Array.newInstance(this.operandClass, 0)).getClass(), operand);
        } catch (ClassCastException e) {
            throw new InvalidConstraintDefinitionException(e);
        }
    }

    /**
     * @inheritDoc
     * @see Constraint#getOperator()
     */
    @Override
    public String getOperator() {
        return this.operator;
    }

    /**
     * @inheritDoc
     * @see Constraint#isComplement()
     */
    public boolean isComplement() {
        return this.complement;
    }

    /**
     * @inheritDoc
     * @see JSONable#getJSON()
     */
    @Override
    public String getJSON() {
        StringBuilder builder = new StringBuilder();
        builder.append(JSONUtils.OPEN_BRACE);
        builder.append(JSONUtils.QUOTE);
        builder.append(OPERATOR_KEY);
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COLON);
        builder.append(JSONUtils.QUOTE);
        builder.append(this.getOperator());
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COMMA);
        builder.append(JSONUtils.QUOTE);
        builder.append(TYPE_KEY);
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COLON);
        builder.append(JSONUtils.QUOTE);
        builder.append(CastUtils.writeClass(this.operandClass));
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COMMA);
        builder.append(JSONUtils.QUOTE);
        builder.append(COMPLEMENT_KEY);
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COLON);
        builder.append(this.complement);
        builder.append(JSONUtils.COMMA);
        builder.append(JSONUtils.QUOTE);
        builder.append(OPERAND_KEY);
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COLON);
        builder.append(JSONUtils.toJSONFormat(this.operand));
        builder.append(JSONUtils.CLOSE_BRACE);
        return builder.toString();
    }
}