AnnotationGroupImpl.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.api.editor.annotation;

import elemental.css.CSSStyleDeclaration;
import elemental.dom.Element;
import elemental.dom.Node;
import elemental.html.DivElement;
import elemental.html.HTMLCollection;
import elemental.util.Mappable;

import org.eclipse.che.ide.api.editor.text.annotation.Annotation;
import org.eclipse.che.ide.util.dom.Elements;

import java.util.ArrayList;
import java.util.List;

import static elemental.css.CSSStyleDeclaration.Position.ABSOLUTE;
import static elemental.css.CSSStyleDeclaration.Position.STATIC;

/**
 * A composite of one or more annotation displays.<br>
 * All annotation are positioned at the same place and the one that is visible is determined by their relative "layer" (
 * {@link Annotation#getLayer()}).<br>
 * All annotation texts ({@link Annotation#getText()}) are aggregated and shown in the annotation tooltip.
 */
class AnnotationGroupImpl implements AnnotationGroup {

    private static final String ELEMENT_ROLE_VALUE_ANNOTATION = "annotation";
    private static final String ELEMENT_ROLE_DATA_PROPERTY    = "eltRole";
    /*
     * This implementation - relies on z-index to display the higher priority annotation - uses data-* attribute (dataset) to store the
     * tooltips
     */
    private static final String MESSAGE_DATASET_NAME          = "annotationMessage";
    private static final String TYPE_DATASET_NAME             = "annotationType";
    private static final String LAYER_DATASET_NAME            = "annotationLayer";
    private static final String OFFSET_DATASET_NAME           = "annotationOffset";

    private elemental.dom.Element mainElement;

    public final static AnnotationGroupImpl create() {
        final AnnotationGroupImpl result = new AnnotationGroupImpl();
        final DivElement element = Elements.createDivElement();
        element.getStyle().setPosition(STATIC);
        result.mainElement = element;
        element.getDataset().setAt(ELEMENT_ROLE_DATA_PROPERTY, ELEMENT_ROLE_VALUE_ANNOTATION);
        return result;
    }

    public final static AnnotationGroupImpl create(final Element existingElement) {
        final AnnotationGroupImpl result = new AnnotationGroupImpl();
        result.mainElement = existingElement;
        return result;
    }

    public elemental.dom.Element asElemental() {
        return this.mainElement;
    }

    @Override
    public final void addAnnotation(final Annotation annotation, int offset) {
        asElemental().appendChild(buildIncludedElement(annotation, offset));
        updateIconVisibility();
    }

    @Override
    public final void removeAnnotation(final Annotation annotation, int offset) {
        final HTMLCollection children = asElemental().getChildren();
        for (int i = 0; i < children.length(); i++) {
            final Node child = (Node)children.at(i);
            if (child instanceof elemental.dom.Element) {
                final elemental.dom.Element element = (elemental.dom.Element)child;
                final Mappable dataset = element.getDataset();
                if (compareStrings(getMessage(dataset), annotation.getText())
                    && getOffset(dataset) == offset
                    && getLayer(dataset) == annotation.getLayer()
                    && compareStrings(getType(dataset), annotation.getType())) {
                    // we may not strictly be on the same annotation instance, but it is not discernible
                    asElemental().removeChild(element);
                    updateIconVisibility();
                    break;
                }
            }
        }
    }

    private elemental.dom.Element buildIncludedElement(Annotation annotation, int offset) {
        final elemental.dom.Element element = annotation.getImageElement();
        final CSSStyleDeclaration style = element.getStyle();
        int layer = annotation.getLayer();
        style.setZIndex(layer);
        style.setPosition(ABSOLUTE);
        style.setTop("0");
        style.setLeft("0");
        style.setRight("0");
        style.setBottom("0");

        element.getDataset().setAt(MESSAGE_DATASET_NAME, annotation.getText());
        element.getDataset().setAt(TYPE_DATASET_NAME, annotation.getType());
        element.getDataset().setAt(LAYER_DATASET_NAME, Integer.toString(layer));
        element.getDataset().setAt(OFFSET_DATASET_NAME, Integer.toString(offset));

        return element;
    }

    private void updateIconVisibility() {
        int maxLayer = 0;
        final HTMLCollection children = asElemental().getChildren();
        for (int i = 0; i < children.length(); i++) {
            final Node child = (Node)children.at(i);
            if (child instanceof elemental.dom.Element) {
                final elemental.dom.Element element = (elemental.dom.Element)child;
                final Mappable dataset = element.getDataset();
                final int layer = getLayer(dataset);
                if(maxLayer < layer){
                    maxLayer = layer;
                }
            }
        }

        for (int i = 0; i < children.length(); i++) {
            final Node child = (Node)children.at(i);
            if (child instanceof elemental.dom.Element) {
                final elemental.dom.Element element = (elemental.dom.Element)child;
                final Mappable dataset = element.getDataset();
                final int layer = getLayer(dataset);
                if(layer >= maxLayer){
                    element.getStyle().removeProperty("display");
                } else {
                    element.getStyle().setDisplay("none");
                }
            }
        }
    }

    @Override
    public Element getElement() {
        return asElemental();
    }

    @Override
    public List<String> getMessages() {
        final List<String> result = new ArrayList<>();

        final HTMLCollection children = asElemental().getChildren();
        for (int i = 0; i < children.length(); i++) {
            final Node child = (Node)children.at(i);
            if (child instanceof elemental.dom.Element) {
                final elemental.dom.Element element = (elemental.dom.Element)child;
                final Mappable dataset = element.getDataset();
                final String message = getMessage(dataset);
                if (message != null) {
                    result.add(message);
                }
            }
        }
        return result;
    }

    @Override
    public int getAnnotationCount() {
        final HTMLCollection children = asElemental().getChildren();
        return children.getLength();
    }

    /**
     * Null-safe string comparison for equality.
     *
     * @param s1 first string to compare
     * @param s2 second string to compare
     * @return true iff both strings are equal
     */
    private static boolean compareStrings(final String s1, final String s2) {
        if (s1 == s2) {
            return true;
        }
        if (s1 == null) {
            return false;
        }
        return s1.equals(s2);
    }

    /**
     * Read the offset value stored in the dataset.
     *
     * @param dataset the dataset
     * @return the offset value or -1 if no valid value is found
     */
    private static int getOffset(final Mappable dataset) {
        final String asString = (String)dataset.at(OFFSET_DATASET_NAME);
        if (asString == null) {
            return -1;
        }
        try {
            return Integer.parseInt(asString);
        } catch (final NumberFormatException e) {
            return -1;
        }
    }

    /**
     * Read the layer value stored in the dataset.
     *
     * @param dataset the dataset
     * @return the layer value or -1 if no valid value is found
     */
    private static int getLayer(final Mappable dataset) {
        final String asString = (String)dataset.at(LAYER_DATASET_NAME);
        if (asString == null) {
            return -1;
        }
        try {
            return Integer.parseInt(asString);
        } catch (final NumberFormatException e) {
            return -1;
        }
    }

    /**
     * Read the type value stored in the dataset.
     *
     * @param dataset the dataset
     * @return the type value
     */
    private static String getType(final Mappable dataset) {
        return (String)dataset.at(TYPE_DATASET_NAME);
    }

    /**
     * Read the message value stored in the dataset.
     *
     * @param dataset the dataset
     * @return the message value
     */
    private static String getMessage(final Mappable dataset) {
        return (String)dataset.at(MESSAGE_DATASET_NAME);
    }

    /**
     * Checks if the element has the annotation marker set.
     * @param element the element to check
     * @return true if the element is marked as 'annotation'
     */
    public final static boolean isAnnotation(final Element element) {
        if (element == null) {
            return false;
        }
        final Object role = element.getDataset().at(ELEMENT_ROLE_DATA_PROPERTY);
        return ELEMENT_ROLE_VALUE_ANNOTATION.equals(role);
    }
}