WhenElement.java

/* 
 * 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.esigate.extension.parallelesi;

import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

import org.esigate.HttpErrorPage;
import org.esigate.parser.future.CharSequenceFuture;
import org.esigate.parser.future.FutureElementType;
import org.esigate.parser.future.FutureParserContext;
import org.esigate.parser.future.StringBuilderFutureAppendable;
import org.esigate.vars.Operations;
import org.esigate.vars.VariablesResolver;

class WhenElement extends BaseElement {

    public static final FutureElementType TYPE = new BaseElementType("<esi:when", "</esi:when") {
        @Override
        public WhenElement newInstance() {
            return new WhenElement();
        }

    };

    private StringBuilderFutureAppendable buf = new StringBuilderFutureAppendable();
    private boolean active = false;

    WhenElement() {
    }

    @Override
    protected boolean parseTag(Tag tag, FutureParserContext ctx) {
        String test = tag.getAttribute("test");
        ChooseElement parent = ctx.findAncestor(ChooseElement.class);
        if (test != null && parent != null) {
            // no other 'when' were active before
            active = !parent.hadConditionSet();
            parent.setCondition(Operations.processOperators(VariablesResolver.replaceAllVariables(test,
                    ctx.getHttpRequest())));
            active &= parent.isCondition();
        }
        return active;
    }

    @Override
    public void onTagEnd(String tag, FutureParserContext ctx) throws IOException, HttpErrorPage {
        if (active) {
            try {
                super.characters(new CharSequenceFuture(buf.get()));
            } catch (ExecutionException e) {
                if (e.getCause() instanceof HttpErrorPage) {
                    throw (HttpErrorPage) e.getCause();
                }
                throw new IOException(e);
            }
        }
    }

    @Override
    public void characters(Future<CharSequence> csq) {
        if (active) {
            buf.enqueueAppend(csq);
        }
    }
}