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This is the ehcache core module. Pair it with other modules for added functionality.
/**
* Copyright Terracotta, Inc.
*
* 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 net.sf.ehcache.config;
/**
* Memory unit: byte-based
* @author Alex Snaps
*/
public enum MemoryUnit {
/**
* BYTES
*/
BYTES(0, 'b') {
/**
* {@inheritDoc}
*/
public long toBytes(final long amount) { return amount; }
/**
* {@inheritDoc}
*/
public long toKiloBytes(final long amount) { return safeShift(amount, KILOBYTES.offset - BYTES.offset); }
/**
* {@inheritDoc}
*/
public long toMegaBytes(final long amount) { return safeShift(amount, MEGABYTES.offset - BYTES.offset); }
/**
* {@inheritDoc}
*/
public long toGigaBytes(final long amount) { return safeShift(amount, GIGABYTES.offset - BYTES.offset); }
},
/**
* KILOBYTES (1024 BYTES)
*/
KILOBYTES(BYTES.offset + MemoryUnit.OFFSET, 'k') {
/**
* {@inheritDoc}
*/
public long toBytes(final long amount) { return safeShift(amount, BYTES.offset - KILOBYTES.offset); }
/**
* {@inheritDoc}
*/
public long toKiloBytes(final long amount) { return amount; }
/**
* {@inheritDoc}
*/
public long toMegaBytes(final long amount) { return safeShift(amount, MEGABYTES.offset - KILOBYTES.offset); }
/**
* {@inheritDoc}
*/
public long toGigaBytes(final long amount) { return safeShift(amount, GIGABYTES.offset - KILOBYTES.offset); }
},
/**
* MEGABYTES (1024 KILOBYTES)
*/
MEGABYTES(KILOBYTES.offset + MemoryUnit.OFFSET, 'm') {
/**
* {@inheritDoc}
*/
public long toBytes(final long amount) { return safeShift(amount, BYTES.offset - MEGABYTES.offset); }
/**
* {@inheritDoc}
*/
public long toKiloBytes(final long amount) { return safeShift(amount, KILOBYTES.offset - MEGABYTES.offset); }
/**
* {@inheritDoc}
*/
public long toMegaBytes(final long amount) { return amount; }
/**
* {@inheritDoc}
*/
public long toGigaBytes(final long amount) { return safeShift(amount, GIGABYTES.offset - MEGABYTES.offset); }
},
/**
* GIGABYTES (1024 MEGABYTES)
*/
GIGABYTES(MEGABYTES.offset + MemoryUnit.OFFSET, 'g') {
/**
* {@inheritDoc}
*/
public long toBytes(final long amount) { return safeShift(amount, BYTES.offset - GIGABYTES.offset); }
/**
* {@inheritDoc}
*/
public long toKiloBytes(final long amount) { return safeShift(amount, KILOBYTES.offset - GIGABYTES.offset); }
/**
* {@inheritDoc}
*/
public long toMegaBytes(final long amount) { return safeShift(amount, MEGABYTES.offset - GIGABYTES.offset); }
/**
* {@inheritDoc}
*/
public long toGigaBytes(final long amount) { return amount; }
};
private static final int OFFSET = 10;
private final int offset;
private final char unit;
private MemoryUnit(final int offset, final char unit) {
this.offset = offset;
this.unit = unit;
}
/**
* Retrieves the unit character for the MemoryUnit
* @return the unit character
*/
public char getUnit() {
return unit;
}
/**
* returns the amount in bytes
* @param amount of the unit
* @return value in bytes
*/
public abstract long toBytes(long amount);
/**
* returns the amount in kilobytes
* @param amount of the unit
* @return value in kilobytes
*/
public abstract long toKiloBytes(long amount);
/**
* returns the amount in megabytes
* @param amount of the unit
* @return value in megabytes
*/
public abstract long toMegaBytes(long amount);
/**
* returns the amount in gigabytes
* @param amount of the unit
* @return value in gigabytes
*/
public abstract long toGigaBytes(long amount);
/**
* Human readable value, with the added unit character as a suffix
* @param amount the amount to print
* @return the String representation
*/
public String toString(final long amount) {
return amount + Character.toString(this.unit);
}
/**
* Returns the MemoryUnit instance based on provided char
* @param unit the unit to look for
* @return the MemoryUnit instance matching the unit
* @throws IllegalArgumentException if no matching MemoryUnit matching the char
*/
public static MemoryUnit forUnit(final char unit) throws IllegalArgumentException {
for (MemoryUnit memoryUnit : values()) {
if (memoryUnit.unit == unit) {
return memoryUnit;
}
}
throw new IllegalArgumentException("'" + unit + "' suffix doesn't match any SizeUnit");
}
/**
* Parses the unit part of a String, if no unit char available, returns {@link MemoryUnit#BYTES}
* @param value the String representation of an amount of memory
* @return the MemoryUnit instance, or BYTES if none
*/
public static MemoryUnit parseUnit(final String value) {
if (hasUnit(value)) {
return forUnit(Character.toLowerCase(value.charAt(value.length() - 1)));
}
return BYTES;
}
/**
* Parses the amount represented by the string, without caring for the unit
* @param value the String representation of an amount of memory
* @return the amount of mem in the unit represented by the potential unit char
* @throws NumberFormatException if not a number (with potential unit char stripped)
*/
public static long parseAmount(final String value) throws NumberFormatException {
if (value == null) {
throw new NullPointerException("Value can't be null!");
}
if (value.length() == 0) {
throw new IllegalArgumentException("Value can't be an empty string!");
}
if (hasUnit(value)) {
return Long.parseLong(value.substring(0, value.length() - 1).trim());
} else {
return Long.parseLong(value);
}
}
/**
* Parses the string for its content, returning the represented value in bytes
* @param value the String representation of an amount of memory
* @return the amount of bytes represented by the string
* @throws NumberFormatException if not a number (with potential unit char stripped)
* @throws IllegalArgumentException if no matching MemoryUnit matching the char
*/
public static long parseSizeInBytes(final String value) throws NumberFormatException, IllegalArgumentException {
if (value.length() == 0) {
throw new IllegalArgumentException("Value can't be an empty string!");
}
MemoryUnit memoryUnit = parseUnit(value);
return memoryUnit.toBytes(parseAmount(value));
}
private static boolean hasUnit(final String value) {
if (value.length() > 0) {
char potentialUnit = value.charAt(value.length() - 1);
return potentialUnit < '0' || potentialUnit > '9';
}
return false;
}
private static long safeShift(final long unit, final long shift) {
if (shift > 0) {
return unit >>> shift;
} else if (shift <= -1 * Long.numberOfLeadingZeros(unit)) {
return Long.MAX_VALUE;
} else {
return unit << -shift;
}
}
}
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