ch.uzh.ifi.seal.permo.lib.ui.swt.builder.StringFieldEditorBuilder.java Source code

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/*******************************************************************************
 * Copyright 2015 Software Evolution and Architecture Lab, University of Zurich
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package ch.uzh.ifi.seal.permo.lib.ui.swt.builder;

import java.util.Optional;
import java.util.function.Predicate;

import org.eclipse.jface.preference.StringFieldEditor;
import org.eclipse.swt.widgets.Composite;

/**
 * A builder for {@link StringFieldEditor}'s.
 */
public class StringFieldEditorBuilder {

    private String name;
    private String labelText;
    private Composite parent;

    private boolean emptyStringAllowed;

    private Optional<Validation> optionalValidation;

    private StringFieldEditorBuilder(final String name, final String labelText, final Composite parent) {
        this.name = name;
        this.labelText = labelText;
        this.parent = parent;
        this.emptyStringAllowed = true;
        this.optionalValidation = Optional.empty();

    }

    /**
     * Sets {@link StringFieldEditor#isEmptyStringAllowed()} to <code>false</code>.
     * 
     * @return the current {@link StringFieldEditorBuilder}
     */
    public StringFieldEditorBuilder emptyNotAllowed() {
        this.emptyStringAllowed = false;
        return this;
    }

    /**
     * Adds a custom validation to the {@link StringFieldEditor}.
     * 
     * @param condition
     *          the condition the value has to meet
     * @param errorMessage
     *          the error message that appears if the condition does not apply
     * @return the current {@link StringFieldEditorBuilder}
     */
    public StringFieldEditorBuilder withValidation(final Predicate<String> condition, final String errorMessage) {
        this.optionalValidation = Optional.of(new Validation(condition, errorMessage));
        return this;
    }

    /**
     * Adds a validation to the {@link StringFieldEditor} that checks whether the string matches the given regular
     * expression.
     * 
     * @param regularExpression
     *          the regular expression to be matched
     * @param errorMessage
     *          the error message that appears if the regular expression is not matched.
     * @return the current {@link StringFieldEditorBuilder}
     */
    public StringFieldEditorBuilder withValidation(final String regularExpression, final String errorMessage) {
        return withValidation((text) -> text.matches(regularExpression), errorMessage);
    }

    public StringFieldEditor create() {
        final StringFieldEditor stringFieldEditor = optionalValidation.isPresent() ? createWithValidation()
                : createWihtoutValidation();
        stringFieldEditor.setEmptyStringAllowed(emptyStringAllowed);
        return stringFieldEditor;
    }

    private StringFieldEditor createWihtoutValidation() {
        return new StringFieldEditor(name, labelText, parent);
    }

    private StringFieldEditor createWithValidation() {
        final Validation validation = this.optionalValidation.get();
        final StringFieldEditor stringFieldEditor = new StringFieldEditor(name, labelText, parent) {

            @Override
            protected boolean checkState() {
                if (!validation.getCondition().test(getStringValue())) {
                    setErrorMessage(validation.getMessage());
                    showErrorMessage();
                    return false;
                }
                return super.checkState();
            }
        };
        return stringFieldEditor;
    }

    /**
     * Creates a new {@link StringFieldEditorBuilder}.
     * 
     * @param name
     *          the name of the {@link StringFieldEditor}
     * @param labelText
     *          the label text of the {@link StringFieldEditor}
     * @param parent
     *          the parent {@link Composite} of the {@link StringFieldEditor}
     * @return the created {@link StringFieldEditorBuilder}
     */
    public static StringFieldEditorBuilder of(final String name, final String labelText, final Composite parent) {
        return new StringFieldEditorBuilder(name, labelText, parent);
    }

    private static class Validation {
        private final Predicate<String> condition;
        private final String message;

        public Validation(final Predicate<String> condition, final String message) {
            this.condition = condition;
            this.message = message;
        }

        public Predicate<String> getCondition() {
            return condition;
        }

        public String getMessage() {
            return message;
        }

    }

}