InsertAttributeModel.java
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.tiles.template;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.tiles.api.Attribute;
import org.apache.tiles.api.TilesContainer;
import org.apache.tiles.api.access.TilesAccess;
import org.apache.tiles.autotag.core.runtime.ModelBody;
import org.apache.tiles.request.Request;
import java.io.IOException;
import java.util.Deque;
/**
* <p>
* <strong>Inserts the value of an attribute into the page.</strong>
* </p>
* <p>
* This tag can be flexibly used to insert the value of an attribute into a
* page. As in other usages in Tiles, every attribute can be determined to have
* a "type", either set explicitly when it was defined, or "computed". If the
* type is not explicit, then if the attribute value is a valid definition, it
* will be inserted as such. Otherwise, if it begins with a "/" character, it
* will be treated as a "template". Finally, if it has not otherwise been
* assigned a type, it will be treated as a String and included without any
* special handling.
* </p>
*
* <p>
* <strong>Example : </strong>
* </p>
*
* <pre>
* <code>
* <tiles:insertAttribute name="body" />
* </code>
* </pre>
* @since 2.2.0
*/
public class InsertAttributeModel {
/**
* The logging object.
*/
private static final Logger LOG = LogManager.getLogger(InsertAttributeModel.class);
/**
* The attribute resolver to use.
*/
private final AttributeResolver attributeResolver;
/**
* Constructor that uses the defaut attribute resolver.
*
* @since 3.0.0
*/
public InsertAttributeModel() {
this(new DefaultAttributeResolver());
}
/**
* Constructor.
*
* @param attributeResolver The attribute resolver to use.
* @since 2.2.0
*/
public InsertAttributeModel(AttributeResolver attributeResolver) {
this.attributeResolver = attributeResolver;
}
/**
* Executes the operation.
*
* @param ignore If <code>true</code>, if an exception happens during
* rendering, of if the attribute is null, the problem will be ignored.
* @param preparer The preparer to invoke before rendering the attribute.
* @param role A comma-separated list of roles. If present, the attribute
* will be rendered only if the current user belongs to one of the roles.
* @param defaultValue The default value of the attribute. To use only if
* the attribute was not computed.
* @param defaultValueRole The default comma-separated list of roles. To use
* only if the attribute was not computed.
* @param defaultValueType The default type of the attribute. To use only if
* the attribute was not computed.
* @param name The name of the attribute.
* @param value The attribute to use immediately, if not null.
* @param flush If <code>true</code>, the response will be flushed after the insert.
* @param request The request.
* @param modelBody The body.
* @throws IOException If an I/O error happens during rendering.
* @since 2.2.0
*/
public void execute(
boolean ignore,
String preparer,
String role,
Object defaultValue,
String defaultValueRole,
String defaultValueType,
String name,
Attribute value,
boolean flush,
Request request,
ModelBody modelBody
) throws IOException {
TilesContainer container = TilesAccess.getCurrentContainer(request);
Deque<Object> composeStack = ComposeStackUtil.getComposeStack(request);
Attribute attribute = resolveAttribute(container, ignore, preparer,
role, defaultValue, defaultValueRole, defaultValueType, name,
value, request);
if (attribute != null) {
composeStack.push(attribute);
}
modelBody.evaluateWithoutWriting();
container = TilesAccess.getCurrentContainer(request);
if (attribute != null) {
attribute = (Attribute) composeStack.pop();
}
renderAttribute(container, ignore, attribute, request);
if (flush) {
request.getWriter().flush();
}
}
/**
* Resolves the attribute. and starts the context.
*
* @param container The Tiles container to use.
* @param ignore If <code>true</code>, if an exception happens during
* rendering, of if the attribute is null, the problem will be ignored.
* @param preparer The preparer to invoke before rendering the attribute.
* @param role A comma-separated list of roles. If present, the attribute
* will be rendered only if the current user belongs to one of the roles.
* @param defaultValue The default value of the attribute. To use only if
* the attribute was not computed.
* @param defaultValueRole The default comma-separated list of roles. To use
* only if the attribute was not computed.
* @param defaultValueType The default type of the attribute. To use only if
* the attribute was not computed.
* @param name The name of the attribute.
* @param value The attribute to use immediately, if not null.
* @param request The request.
* @return The resolved attribute.
*/
private Attribute resolveAttribute(TilesContainer container,
boolean ignore, String preparer, String role, Object defaultValue,
String defaultValueRole, String defaultValueType, String name,
Attribute value, Request request) {
if (preparer != null) {
container.prepare(preparer, request);
}
Attribute attribute = attributeResolver.computeAttribute(container,
value, name, role, ignore, defaultValue, defaultValueRole,
defaultValueType, request);
container.startContext(request);
return attribute;
}
/**
* Renders the attribute as a string.
*
* @param container The Tiles container to use.
* @param ignore If <code>true</code>, if an exception happens during
* rendering, of if the attribute is null, the problem will be ignored.
* @param attribute The attribute to use, previously resolved.
* @param request The request.
* @throws IOException If an I/O error happens during rendering.
*/
private void renderAttribute(TilesContainer container, boolean ignore,
Attribute attribute, Request request) throws IOException {
try {
if (attribute == null && ignore) {
return;
}
container.render(attribute, request);
} catch (IOException | RuntimeException e) {
if (!ignore) {
throw e;
} else if (LOG.isDebugEnabled()) {
LOG.debug("Ignoring exception", e);
}
} finally {
container.endContext(request);
}
}
}