AbstractHelper.java

/*
 * Copyright 2013 Martin Kouba
 *
 * 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 org.trimou.handlebars;

import java.io.IOException;

import org.trimou.engine.config.AbstractConfigurationAware;
import org.trimou.engine.config.EngineConfigurationKey;
import org.trimou.engine.convert.ValueConverter;
import org.trimou.engine.text.TextSupport;
import org.trimou.exception.MustacheException;
import org.trimou.exception.MustacheProblem;

/**
 * An abstract helper that holds a reference to the {@link TextSupport}.
 *
 * @author Martin Kouba
 */
public abstract class AbstractHelper extends AbstractConfigurationAware
        implements Helper {

    private volatile TextSupport textSupport;

    @Override
    protected void init() {
        if (!configuration.getBooleanPropertyValue(
                EngineConfigurationKey.SKIP_VALUE_ESCAPING)) {
            textSupport = configuration.getTextSupport();
        }
    }

    protected boolean isSection(Options options) {
        return Helpers.isSection(options);
    }

    protected boolean isVariable(Options options) {
        return Helpers.isVariable(options);
    }

    protected boolean isUnescapeVariable(Options options) {
        return Helpers.isUnescapeVariable(options);
    }

    /**
     * Escape appended sequence if needed.
     *
     * @param options
     * @param sequence
     * @see TextSupport
     */
    protected void append(Options options, CharSequence sequence) {
        TextSupport textSupport = this.textSupport;
        if (textSupport == null || isUnescapeVariable(options)) {
            options.append(sequence);
        } else {
            try {
                textSupport.appendEscapedHtml(sequence.toString(),
                        options.getAppendable());
            } catch (IOException e) {
                throw new MustacheException(MustacheProblem.RENDER_IO_ERROR, e);
            }
        }
    }

    /**
     *
     * @param value
     * @return the converted value
     * @see ValueConverter
     */
    protected String convertValue(Object value) {
        if (!configuration.getValueConverters().isEmpty()) {
            for (ValueConverter converter : configuration
                    .getValueConverters()) {
                String result = converter.convert(value);
                if (result != null) {
                    return result;
                }
            }
        }
        return value.toString();
    }

    /**
     *
     * @param options
     * @param value
     * @see AbstractHelper#append(Options, CharSequence)
     * @see #convertValue(Object)
     */
    protected void convertAndAppend(Options options, Object value) {
        append(options, convertValue(value));
    }

}