platform/sensinact-common/src/main/java/org/eclipse/sensinact/gateway/common/constraint/Changed.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.JSONUtils;

/**
 * Constraint applying on a value which is required to has changed
 * since a previous value
 *
 * @author <a href="mailto:christophe.munilla@cea.fr">Christophe Munilla</a>
 */
public class Changed extends ConstraintOnComparable<Boolean> {
    public static final String OPERATOR = "changed";

    /**
     * @param complement
     */
    public Changed(ClassLoader classloader) {
        this(classloader, false);
    }

    /**
     * @param complement
     */
    public Changed(ClassLoader classloader, boolean complement) {
        super(classloader, OPERATOR, new Boolean(true), complement);
    }

    /**
     * @inheritDoc
     * @see ConstraintOnComparable#doComplies(java.lang.Object)
     */
    @Override
    protected boolean doComplies(Boolean castedValue) {
        return castedValue.booleanValue() || isComplement();
    }

    /**
     * @inheritDoc
     * @see Constraint#getComplement()
     */
    @Override
    public Constraint getComplement() {
        Changed complement = new Changed(super.classloader, !this.complement);
        return 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(COMPLEMENT_KEY);
        builder.append(JSONUtils.QUOTE);
        builder.append(JSONUtils.COLON);
        builder.append(this.isComplement());
        builder.append(JSONUtils.CLOSE_BRACE);
        return builder.toString();
    }
}