/*
* Copyright 2014-2016 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.hateoas;
import static org.springframework.hateoas.TemplateVariable.VariableType.*;
import lombok.EqualsAndHashCode;
import lombok.Value;
import java.io.Serializable;
import java.util.Arrays;
import java.util.List;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
/**
* A single template variable.
*
* @author Oliver Gierke
*/
@Value
@EqualsAndHashCode
public final class TemplateVariable implements Serializable {
private static final long serialVersionUID = -2731446749851863774L;
String name;
TemplateVariable.VariableType type;
String description;
/**
* Creates a new {@link TemplateVariable} with the given name and type.
*
* @param name must not be {@literal null} or empty.
* @param type must not be {@literal null}.
*/
public TemplateVariable(String name, TemplateVariable.VariableType type) {
this(name, type, "");
}
/**
* Creates a new {@link TemplateVariable} with the given name, type and description.
*
* @param name must not be {@literal null} or empty.
* @param type must not be {@literal null}.
* @param description must not be {@literal null}.
*/
public TemplateVariable(String name, TemplateVariable.VariableType type, String description) {
Assert.hasText(name, "Variable name must not be null or empty!");
Assert.notNull(type, "Variable type must not be null!");
Assert.notNull(description, "Description must not be null!");
this.name = name;
this.type = type;
this.description = description;
}
/**
* Returns whether the variable has a description.
*
* @return
*/
public boolean hasDescription() {
return StringUtils.hasText(description);
}
/**
* Returns whether the template variable is optional, which means the template can be expanded to a URI without a
* value given for that variable.
*
* @return
*/
boolean isRequired() {
return !type.isOptional();
}
/**
* Returns whether the given {@link TemplateVariable} is of the same type as the current one.
*
* @param variable must not be {@literal null}.
* @return
*/
boolean isCombinable(TemplateVariable variable) {
return this.type.canBeCombinedWith(variable.type);
}
/**
* Returns whether the given {@link TemplateVariable} is logically equivalent to the given one. This considers request
* parameter variables equivalent independently from whether they're continued or not.
*
* @param variable
* @return
*/
boolean isEquivalent(TemplateVariable variable) {
return this.name.equals(variable.name) && isCombinable(variable);
}
/**
* Returns whether the current {@link TemplateVariable} is representing a request parameter.
*
* @return
*/
boolean isRequestParameterVariable() {
return type.equals(REQUEST_PARAM) || type.equals(REQUEST_PARAM_CONTINUED);
}
/**
* Returns whether the variable is a fragment one.
*
* @return
*/
boolean isFragment() {
return type.equals(FRAGMENT);
}
/*
* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
String base = String.format("{%s%s}", type.toString(), name);
return StringUtils.hasText(description) ? String.format("%s - %s", base, description) : base;
}
/**
* An enumeration for all supported variable types.
*
* @author Oliver Gierke
*/
public enum VariableType {
PATH_VARIABLE("", false), //
REQUEST_PARAM("?", true), //
REQUEST_PARAM_CONTINUED("&", true), //
SEGMENT("/", true), //
FRAGMENT("#", true);
private static final List<VariableType> COMBINABLE_TYPES = Arrays.asList(REQUEST_PARAM, REQUEST_PARAM_CONTINUED);
private final String key;
private final boolean optional;
private VariableType(String key, boolean optional) {
this.key = key;
this.optional = optional;
}
/**
* Returns whether the variable of this type is optional.
*
* @return
*/
public boolean isOptional() {
return optional;
}
public boolean canBeCombinedWith(VariableType type) {
return this.equals(type) || COMBINABLE_TYPES.contains(this) && COMBINABLE_TYPES.contains(type);
}
/**
* Returns the {@link VariableType} for the given variable key.
*
* @param key must not be {@literal null}.
* @return
*/
public static TemplateVariable.VariableType from(String key) {
for (TemplateVariable.VariableType type : values()) {
if (type.key.equals(key)) {
return type;
}
}
throw new IllegalArgumentException("Unsupported variable type " + key + "!");
}
/*
* (non-Javadoc)
* @see java.lang.Enum#toString()
*/
@Override
public String toString() {
return key;
}
}
}