org.springframework.web.servlet.view.xslt.TransformerUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2006 the original author or authors.
*
* 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.springframework.web.servlet.view.xslt;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import org.springframework.util.Assert;
/**
* Contains common behavior relating to {@link Transformer Transformers}.
*
* @author Rick Evans
* @since 2.0
*/
public abstract class TransformerUtils {
/**
* The indent amount of characters if
* {@link #enableIndenting(javax.xml.transform.Transformer) indenting is enabled}.
* Defaults to "2".
*/
public static final int DEFAULT_INDENT_AMOUNT = 2;
/**
* Enable indenting for the supplied {@link Transformer}.
*
If the underlying XSLT engine is Xalan, then the special output
* key indent-amount will be also be set to a value
* of {@link #DEFAULT_INDENT_AMOUNT} characters.
* @param transformer the target transformer
* @throws IllegalArgumentException if the supplied {@link Transformer} is null
* @see Transformer#setOutputProperty(String, String)
* @see OutputKeys#INDENT
*/
public static void enableIndenting(Transformer transformer) {
enableIndenting(transformer, DEFAULT_INDENT_AMOUNT);
}
/**
* Enable indenting for the supplied {@link Transformer}.
*
If the underlying XSLT engine is Xalan, then the special output
* key indent-amount will be also be set to a value
* of {@link #DEFAULT_INDENT_AMOUNT} characters.
* @param transformer the target transformer
* @param indentAmount the size of the indent (2 characters, 3 characters, etc.)
* @throws IllegalArgumentException if the supplied {@link Transformer} is null
* or if the supplied indent amount is less than zero (that is, negative)
* @see Transformer#setOutputProperty(String, String)
* @see OutputKeys#INDENT
*/
public static void enableIndenting(Transformer transformer, int indentAmount) {
Assert.notNull(transformer);
Assert.isTrue(indentAmount > -1, "The indent amount cannot be less than zero : got " + indentAmount);
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
try {
// Xalan-specific, but this is the most common XSLT engine in any case
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", String.valueOf(indentAmount));
}
catch (IllegalArgumentException ignored) {
}
}
/**
* Disable indenting for the supplied {@link Transformer}.
* @param transformer the target transformer
* @throws IllegalArgumentException if the supplied {@link Transformer} is null
* @see OutputKeys#INDENT
*/
public static void disableIndenting(Transformer transformer) {
Assert.notNull(transformer);
transformer.setOutputProperty(OutputKeys.INDENT, "no");
}
}