org.springframework.web.util.UriTemplate Maven / Gradle / Ivy
/*
* Copyright 2002-2009 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.util;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.springframework.util.Assert;
/**
* Represents a URI template. An URI template is a URI-like String that contained variables marked of in braces
* ({, }), which can be expanded to produce a URI. See {@link #expand(Map)},
* {@link #expand(Object[])}, and {@link #match(String)} for example usages.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @see URI Templates
* @since 3.0
*/
public class UriTemplate {
/** Captures URI template variable names. */
private static final Pattern NAMES_PATTERN = Pattern.compile("\\{([^/]+?)\\}");
/** Replaces template variables in the URI template. */
private static final String VALUE_REGEX = "(.*)";
private final List variableNames;
private final Pattern matchPattern;
private final String uriTemplate;
/**
* Construct a new {@link UriTemplate} with the given URI String.
* @param uriTemplate the URI template string
*/
public UriTemplate(String uriTemplate) {
Parser parser = new Parser(uriTemplate);
this.uriTemplate = uriTemplate;
this.variableNames = parser.getVariableNames();
this.matchPattern = parser.getMatchPattern();
}
/**
* Return the names of the variables in the template, in order.
* @return the template variable names
*/
public final List getVariableNames() {
return this.variableNames;
}
/**
* Given the Map of variables, expands this template into a URI. The Map keys represent variable names, the Map values
* variable values. The order of variables is not significant. Example:
*
* UriTemplate template = new UriTemplate("http://example.com/hotels/{hotel}/bookings/{booking}");
* Map<String, String> uriVariables = new HashMap<String, String>();
* uriVariables.put("booking", "42");
* uriVariables.put("hotel", "1");
* System.out.println(template.expand(uriVariables));
*
* will print: http://example.com/hotels/1/bookings/42
* @param uriVariables the map of URI variables
* @return the expanded URI
* @throws IllegalArgumentException if uriVariables is null; or if it does not contain values
* for all the variable names
*/
public URI expand(Map uriVariables) {
Assert.notNull(uriVariables, "'uriVariables' must not be null");
Object[] values = new String[this.variableNames.size()];
for (int i = 0; i < this.variableNames.size(); i++) {
String name = this.variableNames.get(i);
if (!uriVariables.containsKey(name)) {
throw new IllegalArgumentException("'uriVariables' Map has no value for '" + name + "'");
}
values[i] = uriVariables.get(name);
}
return expand(values);
}
/**
* Given an array of variables, expand this template into a full URI. The array represent variable values.
* The order of variables is significant. Example:
will print: http://example.com/hotels/1/bookings/42
* @param uriVariableValues the array of URI variables
* @return the expanded URI
* @throws IllegalArgumentException if uriVariables is null; or if it does not contain
* sufficient variables
*/
public URI expand(Object... uriVariableValues) {
Assert.notNull(uriVariableValues, "'uriVariableValues' must not be null");
if (uriVariableValues.length != this.variableNames.size()) {
throw new IllegalArgumentException(
"Invalid amount of variables values in [" + this.uriTemplate + "]: expected " +
this.variableNames.size() + "; got " + uriVariableValues.length);
}
Matcher matcher = NAMES_PATTERN.matcher(this.uriTemplate);
StringBuffer buffer = new StringBuffer();
int i = 0;
while (matcher.find()) {
String uriVariable = uriVariableValues[i++].toString();
matcher.appendReplacement(buffer, uriVariable);
}
matcher.appendTail(buffer);
return encodeUri(buffer.toString());
}
/**
* Indicate whether the given URI matches this template.
* @param uri the URI to match to
* @return true if it matches; false otherwise
*/
public boolean matches(String uri) {
if (uri == null) {
return false;
}
Matcher matcher = this.matchPattern.matcher(uri);
return matcher.matches();
}
/**
* Match the given URI to a map of variable values. Keys in the returned map are variable names, values are variable
* values, as occurred in the given URI. Example:
UriTemplate template = new
* UriTemplate("http://example.com/hotels/{hotel}/bookings/{booking}"); System.out.println(template.match("http://example.com/hotels/1/bookings/42"));
* will print: {hotel=1, booking=42}
* @param uri the URI to match to
* @return a map of variable values
*/
public Map match(String uri) {
Assert.notNull(uri, "'uri' must not be null");
Map result = new LinkedHashMap(this.variableNames.size());
Matcher matcher = this.matchPattern.matcher(uri);
if (matcher.find()) {
for (int i = 1; i <= matcher.groupCount(); i++) {
String name = this.variableNames.get(i - 1);
String value = matcher.group(i);
result.put(name, value);
}
}
return result;
}
@Override
public String toString() {
return this.uriTemplate;
}
private static URI encodeUri(String uri) {
try {
String encoded = UriUtils.encodeUri(uri, "UTF-8");
return new URI(encoded);
}
catch (UnsupportedEncodingException ex) {
// should not happen, UTF-8 is always supported
throw new IllegalStateException(ex);
}
catch (URISyntaxException ex) {
throw new IllegalArgumentException("Could not create URI from [" + uri + "]: " + ex);
}
}
/**
* Static inner class to parse uri template strings into a matching regular expression.
*/
private static class Parser {
private final List variableNames = new LinkedList();
private final StringBuilder patternBuilder = new StringBuilder();
private Parser(String uriTemplate) {
Assert.hasText(uriTemplate, "'uriTemplate' must not be null");
Matcher m = NAMES_PATTERN.matcher(uriTemplate);
int end = 0;
while (m.find()) {
this.patternBuilder.append(encodeAndQuote(uriTemplate, end, m.start()));
this.patternBuilder.append(VALUE_REGEX);
this.variableNames.add(m.group(1));
end = m.end();
}
this.patternBuilder.append(encodeAndQuote(uriTemplate, end, uriTemplate.length()));
int lastIdx = this.patternBuilder.length() - 1;
if (lastIdx >= 0 && this.patternBuilder.charAt(lastIdx) == '/') {
this.patternBuilder.deleteCharAt(lastIdx);
}
}
private String encodeAndQuote(String fullPath, int start, int end) {
if (start == end) {
return "";
}
String result = encodeUri(fullPath.substring(start, end)).toASCIIString();
return Pattern.quote(result);
}
private List getVariableNames() {
return Collections.unmodifiableList(this.variableNames);
}
private Pattern getMatchPattern() {
return Pattern.compile(this.patternBuilder.toString());
}
}
}