Utils.java
/*
* Copyright 2011 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 com.jayway.jsonpath.internal;
import com.jayway.jsonpath.JsonPathException;
import java.io.Closeable;
import java.io.IOException;
import java.io.StringWriter;
import java.util.Iterator;
public final class Utils {
// accept a collection of objects, since all objects have toString()
public static String join(String delimiter, String wrap, Iterable<?> objs) {
Iterator<?> iter = objs.iterator();
if (!iter.hasNext()) {
return "";
}
StringBuilder buffer = new StringBuilder();
buffer.append(wrap).append(iter.next()).append(wrap);
while (iter.hasNext()) {
buffer.append(delimiter).append(wrap).append(iter.next()).append(wrap);
}
return buffer.toString();
}
// accept a collection of objects, since all objects have toString()
public static String join(String delimiter, Iterable<?> objs) {
return join(delimiter, "", objs);
}
public static String concat(CharSequence... strings) {
if (strings.length == 0) {
return "";
}
if (strings.length == 1) {
return strings[0].toString();
}
int length = 0;
// -1 = no result, -2 = multiple results
int indexOfSingleNonEmptyString = -1;
for (int i = 0; i < strings.length; i++) {
CharSequence charSequence = strings[i];
int len = charSequence.length();
length += len;
if (indexOfSingleNonEmptyString != -2 && len > 0) {
if (indexOfSingleNonEmptyString == -1) {
indexOfSingleNonEmptyString = i;
} else {
indexOfSingleNonEmptyString = -2;
}
}
}
if (length == 0) {
return "";
}
if (indexOfSingleNonEmptyString > 0) {
return strings[indexOfSingleNonEmptyString].toString();
}
StringBuilder sb = new StringBuilder(length);
for (CharSequence charSequence : strings) {
sb.append(charSequence);
}
return sb.toString();
}
//---------------------------------------------------------
//
// IO
//
//---------------------------------------------------------
public static void closeQuietly(Closeable closeable) {
try {
if (closeable != null) {
closeable.close();
}
} catch (IOException ignore) {
}
}
public static String escape(String str, boolean escapeSingleQuote) {
if (str == null) {
return null;
}
int len = str.length();
StringWriter writer = new StringWriter(len * 2);
for (int i = 0; i < len; i++) {
char ch = str.charAt(i);
// handle unicode
if (ch > 0xfff) {
writer.write("\\u" + hex(ch));
} else if (ch > 0xff) {
writer.write("\\u0" + hex(ch));
} else if (ch > 0x7f) {
writer.write("\\u00" + hex(ch));
} else if (ch < 32) {
switch (ch) {
case '\b':
writer.write('\\');
writer.write('b');
break;
case '\n':
writer.write('\\');
writer.write('n');
break;
case '\t':
writer.write('\\');
writer.write('t');
break;
case '\f':
writer.write('\\');
writer.write('f');
break;
case '\r':
writer.write('\\');
writer.write('r');
break;
default :
if (ch > 0xf) {
writer.write("\\u00" + hex(ch));
} else {
writer.write("\\u000" + hex(ch));
}
break;
}
} else {
switch (ch) {
case '\'':
if (escapeSingleQuote) {
writer.write('\\');
}
writer.write('\'');
break;
case '"':
writer.write('\\');
writer.write('"');
break;
case '\\':
writer.write('\\');
writer.write('\\');
break;
case '/':
writer.write('\\');
writer.write('/');
break;
default :
writer.write(ch);
break;
}
}
}
return writer.toString();
}
public static String unescape(String str) {
if (str == null) {
return null;
}
int len = str.length();
StringWriter writer = new StringWriter(len);
StringBuilder unicode = new StringBuilder(4);
boolean hadSlash = false;
boolean inUnicode = false;
for (int i = 0; i < len; i++) {
char ch = str.charAt(i);
if (inUnicode) {
unicode.append(ch);
if (unicode.length() == 4) {
try {
int value = Integer.parseInt(unicode.toString(), 16);
writer.write((char) value);
unicode.setLength(0);
inUnicode = false;
hadSlash = false;
} catch (NumberFormatException nfe) {
throw new JsonPathException("Unable to parse unicode value: " + unicode, nfe);
}
}
continue;
}
if (hadSlash) {
hadSlash = false;
switch (ch) {
case '\\':
writer.write('\\');
break;
case '\'':
writer.write('\'');
break;
case '\"':
writer.write('"');
break;
case 'r':
writer.write('\r');
break;
case 'f':
writer.write('\f');
break;
case 't':
writer.write('\t');
break;
case 'n':
writer.write('\n');
break;
case 'b':
writer.write('\b');
break;
case 'u':
{
inUnicode = true;
break;
}
default :
writer.write(ch);
break;
}
continue;
} else if (ch == '\\') {
hadSlash = true;
continue;
}
writer.write(ch);
}
if (hadSlash) {
writer.write('\\');
}
return writer.toString();
}
/**
* Returns an upper case hexadecimal <code>String</code> for the given
* character.
*
* @param ch The character to map.
* @return An upper case hexadecimal <code>String</code>
*/
public static String hex(char ch) {
return Integer.toHexString(ch).toUpperCase();
}
/**
* <p>Checks if a CharSequence is empty ("") or null.</p>
* <p/>
* <pre>
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
* </pre>
* <p/>
* <p>NOTE: This method changed in Lang version 2.0.
* It no longer trims the CharSequence.
* That functionality is available in isBlank().</p>
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is empty or null
* @since 3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)
*/
public static boolean isEmpty(CharSequence cs) {
return cs == null || cs.length() == 0;
}
/**
* Used by the indexOf(CharSequence methods) as a green implementation of indexOf.
*
* @param cs the {@code CharSequence} to be processed
* @param searchChar the {@code CharSequence} to be searched for
* @param start the start index
* @return the index where the search sequence was found
*/
static int indexOf(CharSequence cs, CharSequence searchChar, int start) {
return cs.toString().indexOf(searchChar.toString(), start);
}
//---------------------------------------------------------
//
// Validators
//
//---------------------------------------------------------
/**
* <p>Validate that the specified argument is not {@code null};
* otherwise throwing an exception with the specified message.
* <p/>
* <pre>Validate.notNull(myObject, "The object must not be null");</pre>
*
* @param <T> the object type
* @param object the object to check
* @param message the {@link String#format(String, Object...)} exception message if invalid, not null
* @return the validated object (never {@code null} for method chaining)
* @throws NullPointerException if the object is {@code null}
*/
public static <T> T notNull(T object, String message) {
if (object == null) {
throw new IllegalArgumentException(message);
}
return object;
}
/**
* <p>Validate that the specified argument is not {@code null};
* otherwise throwing an exception with the specified message.
* <p/>
* <pre>Validate.notNull(myObject, "The object must not be null");</pre>
*
* @param <T> the object type
* @param object the object to check
* @param message the {@link String#format(String, Object...)} exception message if invalid, not null
* @param values the optional values for the formatted exception message
* @return the validated object (never {@code null} for method chaining)
* @throws NullPointerException if the object is {@code null}
*/
public static <T> T notNull(T object, String message, Object... values) {
if (object == null) {
throw new IllegalArgumentException(String.format(message, values));
}
return object;
}
/**
* <p>Validate that the argument condition is {@code true}; otherwise
* throwing an exception with the specified message. This method is useful when
* validating according to an arbitrary boolean expression, such as validating a
* primitive number or using your own custom validation expression.</p>
* <p/>
* <pre>Validate.isTrue(i > 0.0, "The value must be greater than zero: %d", i);</pre>
* <p/>
* <p>For performance reasons, the long value is passed as a separate parameter and
* appended to the exception message only in the case of an error.</p>
*
* @param expression the boolean expression to check
* @param message
* @throws IllegalArgumentException if expression is {@code false}
*/
public static void isTrue(boolean expression, String message) {
if (expression == false) {
throw new IllegalArgumentException(message);
}
}
/**
* Check if one and only one condition is true; otherwise
* throw an exception with the specified message.
*
* @param message error describing message
* @param expressions the boolean expressions to check
* @throws IllegalArgumentException if zero or more than one expressions are true
*/
public static void onlyOneIsTrue(final String message, final boolean... expressions) {
if (!onlyOneIsTrueNonThrow(expressions)) {
throw new IllegalArgumentException(message);
}
}
public static boolean onlyOneIsTrueNonThrow(final boolean... expressions) {
int count = 0;
for (final boolean expression : expressions) {
if (expression && ++count > 1) {
return false;
}
}
return 1 == count;
}
/**
* <p>Validate that the specified argument character sequence is
* neither {@code null} nor a length of zero (no characters);
* otherwise throwing an exception with the specified message.
* <p/>
* <pre>Validate.notEmpty(myString, "The string must not be empty");</pre>
*
* @param <T> the character sequence type
* @param chars the character sequence to check, validated not null by this method
* @param message the {@link String#format(String, Object...)} exception message if invalid, not null
* @return the validated character sequence (never {@code null} method for chaining)
* @throws NullPointerException if the character sequence is {@code null}
* @throws IllegalArgumentException if the character sequence is empty
*/
public static <T extends CharSequence> T notEmpty(T chars, String message) {
if (chars == null || chars.length() == 0) {
throw new IllegalArgumentException(message);
}
return chars;
}
/**
* <p>Validate that the specified argument character sequence is
* neither {@code null} nor a length of zero (no characters);
* otherwise throwing an exception with the specified message.
* <p/>
* <pre>Validate.notEmpty(myString, "The string must not be empty");</pre>
*
* @param bytes the bytes to check, validated not null by this method
* @param message the {@link String#format(String, Object...)} exception message if invalid, not null
* @return the validated character sequence (never {@code null} method for chaining)
* @throws NullPointerException if the character sequence is {@code null}
* @throws IllegalArgumentException if the character sequence is empty
*/
public static byte[] notEmpty(byte[] bytes, String message) {
if (bytes == null || bytes.length == 0) {
throw new IllegalArgumentException(message);
}
return bytes;
}
/**
* <p>Validate that the specified argument character sequence is
* neither {@code null} nor a length of zero (no characters);
* otherwise throwing an exception with the specified message.
* <p/>
* <pre>Validate.notEmpty(myString, "The string must not be empty");</pre>
*
* @param <T> the character sequence type
* @param chars the character sequence to check, validated not null by this method
* @param message the {@link String#format(String, Object...)} exception message if invalid, not null
* @param values the optional values for the formatted exception message, null array not recommended
* @return the validated character sequence (never {@code null} method for chaining)
* @throws NullPointerException if the character sequence is {@code null}
* @throws IllegalArgumentException if the character sequence is empty
*/
public static <T extends CharSequence> T notEmpty(T chars, String message, Object... values) {
if (chars == null || chars.length() == 0) {
throw new IllegalArgumentException(String.format(message, values));
}
return chars;
}
//---------------------------------------------------------
//
// Converters
//
//---------------------------------------------------------
public static String toString(Object o) {
if (null == o) {
return null;
}
return o.toString();
}
private Utils() {
}
}