org.apache.abdera.i18n.templates.Template Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. 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. For additional information regarding
* copyright in this work, please see the NOTICE file in the top level
* directory of this distribution.
*/
package org.apache.abdera.i18n.templates;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.abdera.i18n.text.CharUtils;
/**
* Used to evaluate a URI Template. Instances are immutable, cloneable, serializable and threadsafe.
*/
@SuppressWarnings("unchecked")
public final class Template implements Iterable, Cloneable, Serializable {
private static final long serialVersionUID = -613907262632631896L;
private static final Evaluator EVALUATOR = new Evaluator();
private static final Pattern VARIABLE = Pattern.compile("\\{[^{}]+\\}");
private static final String TOKEN_START = "\\{";
private static final String TOKEN_STOP = "\\}";
private final String pattern;
private final String[] tokens;
private final String[] variables;
/**
* @param pattern A URI Template
*/
public Template(String pattern) {
this.pattern = CharUtils.stripBidiInternal(pattern);
this.tokens = initTokens();
this.variables = initVariables();
}
/**
* Return the URI Template pattern
*/
public String getPattern() {
return pattern;
}
/**
* IRI Templates that contain bidirectional characters will typically not display properly in unicode enabled
* environments. This method return the Template with appropriate bidi control characters to ensure that the
* Template can be rendered properly for display
*/
public String getPatternForDisplay() {
String pattern = this.pattern;
for (String token : this) {
pattern = replace(pattern, token, forDisplay(token));
}
return CharUtils.wrapBidi(pattern, CharUtils.LRO);
}
private static String forDisplay(String token) {
String[] splits = token.split("\\|");
StringBuilder buf = new StringBuilder();
buf.append('{');
if (splits.length == 1) {
String[] pair = splits[0].split("\\s*=\\s*");
buf.append(CharUtils.wrapBidi(pair[0], CharUtils.LRE));
if (pair.length > 1) {
buf.append('=');
buf.append(pair[1]);
}
} else {
buf.append(splits[0]);
buf.append('|');
buf.append(splits[1]);
buf.append('|');
String[] vars = splits[2].split("\\s*,\\s*");
int i = 0;
for (String var : vars) {
if (i++ > 0)
buf.append(",");
String[] pair = var.split("\\s*=\\s*");
buf.append(CharUtils.wrapBidi(pair[0], CharUtils.LRE));
if (pair.length > 1) {
buf.append('=');
buf.append(pair[1]);
}
}
}
buf.append('}');
return buf.toString();
}
/**
* Iterate the template tokens
*/
public Iterator iterator() {
return Arrays.asList(tokens).iterator();
}
/**
* Return the array of template variables
*/
private String[] initTokens() {
Matcher matcher = VARIABLE.matcher(pattern);
List tokens = new ArrayList();
while (matcher.find()) {
String token = matcher.group();
token = token.substring(1, token.length() - 1);
if (!tokens.contains(token))
tokens.add(token);
}
return tokens.toArray(new String[tokens.size()]);
}
private String[] initVariables() {
List list = new ArrayList();
for (String token : this) {
String[] vars = EVALUATOR.getVariables(token);
for (String var : vars) {
if (!list.contains(var))
list.add(var);
}
}
return list.toArray(new String[list.size()]);
}
/**
* Return the array of template variables
*/
public String[] getVariables() {
return variables;
}
/**
* Expand the URI Template using the specified Context.
*
* @param context The Context impl used to resolve variable values
* @return An expanded URI
*/
public String expand(Context context) {
String pattern = this.pattern;
for (String token : this) {
pattern = replace(pattern, token, EVALUATOR.evaluate(token, context));
}
return pattern;
}
/**
* Expand the URI Template using the non-private fields and methods of the specified object to resolve the template
* tokens
*/
public String expand(Object object) {
return expand(object, false);
}
/**
* Expand the template using the non-private fields and methods of the specified object to resolve the template
* tokens. If isiri is true, IRI escaping rules will be used.
*/
public String expand(Object object, boolean isiri) {
return expand(object instanceof Context ? (Context)object : object instanceof Map
? new HashMapContext((Map)object, isiri) : new ObjectContext(object, isiri));
}
private String replace(String pattern, String token, String value) {
return pattern.replaceAll(TOKEN_START + Pattern.quote(token) + TOKEN_STOP, value);
}
/**
* Clone this Template instance
*/
public Template clone() {
try {
return (Template)super.clone();
} catch (Throwable e) {
return new Template(pattern); // not going to happen, but just in case
}
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((pattern == null) ? 0 : pattern.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
final Template other = (Template)obj;
if (pattern == null) {
if (other.pattern != null)
return false;
} else if (!pattern.equals(other.pattern))
return false;
return true;
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append("V:" + getPatternForDisplay());
buf.append('\n');
buf.append("L:" + CharUtils.wrapBidi(getPattern(), CharUtils.LRO));
buf.append('\n');
return buf.toString();
}
public String explain() {
StringBuilder buf = new StringBuilder();
try {
explain(buf);
} catch (IOException e) {
throw new RuntimeException(e);
}
return buf.toString();
}
public void explain(Appendable buf) throws IOException {
buf.append("Template:");
buf.append('\n');
buf.append("\t" + getPatternForDisplay());
buf.append('\n');
buf.append('\n');
buf.append(" Variables:");
buf.append('\n');
String[] vars = getVariables();
for (String var : vars) {
buf.append('\t');
buf.append(var);
buf.append('\n');
}
buf.append('\n');
buf.append(" Tokens:");
buf.append('\n');
for (String token : this) {
buf.append('\t');
buf.append(forDisplay(token) + " \n\t\t ");
EVALUATOR.explain(token, buf);
buf.append('\n');
}
buf.append('\n');
buf.append(" Example:");
buf.append('\n');
HashMapContext c = new HashMapContext();
for (String var : vars) {
c.put(var, "foo");
buf.append("\t" + var + " = " + "foo");
buf.append('\n');
}
buf.append('\n');
buf.append("\t" + expand(c));
buf.append('\n');
buf.append('\n');
c.clear();
for (int i = 0; i < vars.length; i++) {
String var = vars[i];
if (i % 2 == 1) {
c.put(var, "foo");
buf.append("\t" + var + " = " + "foo");
buf.append('\n');
} else {
buf.append("\t" + var + " = null");
buf.append('\n');
}
}
buf.append('\n');
buf.append("\t" + expand(c));
buf.append('\n');
buf.append('\n');
c.clear();
for (int i = 0; i < vars.length; i++) {
String var = vars[i];
if (i % 2 == 0) {
c.put(var, "foo");
buf.append("\t" + var + " = " + "foo");
buf.append('\n');
} else {
buf.append("\t" + var + " = null");
buf.append('\n');
}
}
buf.append('\n');
buf.append("\t" + expand(c));
}
public static String expand(String pattern, Context context) {
if (context == null || pattern == null)
throw new IllegalArgumentException();
Template template = new Template(pattern);
return template.expand(context);
}
public static String expand(String pattern, Object object) {
return expand(pattern, object, false);
}
public static String expand(String pattern, Object object, boolean isiri) {
if (object == null || pattern == null)
throw new IllegalArgumentException();
Template template = new Template(pattern);
return template.expand(object, isiri);
}
/**
* Use an Object annotated with the URITemplate annotation to expand a template
*/
public static String expandAnnotated(Object object) {
if (object == null)
throw new IllegalArgumentException();
Class _class = object.getClass();
URITemplate uritemplate = (URITemplate)_class.getAnnotation(URITemplate.class);
if (uritemplate != null) {
return expand(uritemplate.value(), object, uritemplate.isiri());
} else {
throw new IllegalArgumentException("No URI Template provided");
}
}
public static String explain(String pattern) {
return new Template(pattern).explain();
}
public static void explain(String pattern, Appendable buf) throws IOException {
new Template(pattern).explain(buf);
}
}
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