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Java 1.8+ Library with tons of utility classes required in all projects
/*
* Copyright (C) 2014-2024 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* 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.helger.commons.string;
import java.util.Arrays;
import java.util.function.BooleanSupplier;
import java.util.function.DoublePredicate;
import java.util.function.IntPredicate;
import java.util.function.LongPredicate;
import java.util.function.Predicate;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.NotThreadSafe;
import com.helger.commons.equals.EqualsHelper;
import com.helger.commons.functional.IBooleanPredicate;
import com.helger.commons.functional.ICharPredicate;
/**
* This is a utility class for easier toString method creations. It
* assumes that the toString method is only used for the
* representation of the internal state and not for creating human readable
* formats.
*
* A real world example for a final class derived from {@link Object} or a base
* class looks like this:
*
*
*
* @Override
* public String toString ()
* {
* return new ToStringGenerator (this).append ("member1", member1).append ("member2", member2).toString ();
* }
*
*
* For a derived class, the typical code looks like this, assuming that the base
* class also used the {@link ToStringGenerator}:
*
*
*
* @Override
* public String toString ()
* {
* return ToStringGenerator.getDerived (super.toString ())
* .append ("member3", member3)
* .append ("member4", member4)
* .toString ();
* }
*
*
* @author Philip Helger
*/
@NotThreadSafe
public final class ToStringGenerator
{
/** String to be emitted for null values */
public static final String CONSTANT_NULL = "null";
/** String to be emitted for this values */
public static final String CONSTANT_THIS = "this";
/** String to be emited for password values */
public static final String CONSTANT_PASSWORD = "****";
private static final int FIRST_FIELD = 1;
private static final int APPENDED_CLOSING_BRACKET = 2;
private final StringBuilder m_aSB = new StringBuilder ("[");
private final Object m_aSrc;
private int m_nIndex = 0;
public ToStringGenerator (@Nullable final Object aSrc)
{
if (aSrc != null)
{
final String sClassName = aSrc.getClass ().getName ();
final int nIndex = sClassName.lastIndexOf ('.');
m_aSB.append (nIndex == -1 ? sClassName : sClassName.substring (nIndex + 1))
.append ("@0x")
.append (StringHelper.getHexStringLeadingZero (System.identityHashCode (aSrc), 8));
}
m_aSrc = aSrc;
}
private void _beforeAddField ()
{
if ((m_nIndex & FIRST_FIELD) == 0)
{
m_nIndex |= FIRST_FIELD;
// Only if a valid source object was provided
if (m_aSB.length () > 1)
m_aSB.append (": ");
}
else
m_aSB.append ("; ");
}
@Nonnull
private ToStringGenerator _appendSuper (final String sSuper)
{
_beforeAddField ();
m_aSB.append (sSuper);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final boolean aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final boolean [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final byte aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final byte [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final char aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append ('\'').append (aValue).append ('\'');
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final char [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final double aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final double [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final float aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final float [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final int aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final int [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final long aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final long [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, final short aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (aValue);
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final short [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=').append (Arrays.toString (aValue));
return this;
}
@Nonnull
public ToStringGenerator appendPassword (@Nonnull final String sField)
{
return append (sField, CONSTANT_PASSWORD);
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final Enum aValue)
{
return append (sField, String.valueOf (aValue));
}
@Nonnull
private ToStringGenerator _appendArray (@Nonnull final String sField, @Nonnull final Object aValue)
{
// Passed value is an array
final Class aCompType = aValue.getClass ().getComponentType ();
if (aCompType.isPrimitive ())
{
// Assuming byte[] happens most often
if (aCompType.equals (byte.class))
return append (sField, (byte []) aValue);
if (aCompType.equals (boolean.class))
return append (sField, (boolean []) aValue);
if (aCompType.equals (char.class))
return append (sField, (char []) aValue);
if (aCompType.equals (double.class))
return append (sField, (double []) aValue);
if (aCompType.equals (float.class))
return append (sField, (float []) aValue);
if (aCompType.equals (int.class))
return append (sField, (int []) aValue);
if (aCompType.equals (long.class))
return append (sField, (long []) aValue);
if (aCompType.equals (short.class))
return append (sField, (short []) aValue);
}
return append (sField, (Object []) aValue);
}
@Nonnull
private String _getObjectValue (@Nullable final Object aValue)
{
if (aValue == null)
return CONSTANT_NULL;
return EqualsHelper.identityEqual (aValue, m_aSrc) ? CONSTANT_THIS : aValue.toString ();
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final Object aValue)
{
if (aValue != null && aValue.getClass ().isArray ())
return _appendArray (sField, aValue);
_beforeAddField ();
// Avoid endless loop with base object
m_aSB.append (sField).append ('=').append (_getObjectValue (aValue));
return this;
}
@Nonnull
public ToStringGenerator append (@Nonnull final String sField, @Nullable final Object [] aValue)
{
_beforeAddField ();
m_aSB.append (sField).append ('=');
if (aValue == null)
m_aSB.append (CONSTANT_NULL);
else
{
final int nMax = aValue.length - 1;
if (nMax == -1)
m_aSB.append ("[]");
else
{
m_aSB.append ('[');
for (int i = 0;; i++)
{
// Avoid endless loop with base object
m_aSB.append (_getObjectValue (aValue[i]));
if (i == nMax)
break;
m_aSB.append (", ");
}
m_aSB.append (']');
}
}
return this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final boolean bValue,
@Nonnull final IBooleanPredicate aFilter)
{
return aFilter.test (bValue) ? append (sField, bValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final boolean bValue,
@Nonnull final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? append (sField, bValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final char cValue,
@Nonnull final ICharPredicate aFilter)
{
return aFilter.test (cValue) ? append (sField, cValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final char cValue,
@Nonnull final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? append (sField, cValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final int nValue,
@Nonnull final IntPredicate aFilter)
{
return aFilter.test (nValue) ? append (sField, nValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final int nValue,
@Nonnull final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? append (sField, nValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final long nValue,
@Nonnull final LongPredicate aFilter)
{
return aFilter.test (nValue) ? append (sField, nValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final long nValue,
@Nonnull final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? append (sField, nValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final double dValue,
@Nonnull final DoublePredicate aFilter)
{
return aFilter.test (dValue) ? append (sField, dValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
final double dValue,
@Nonnull final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? append (sField, dValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
@Nullable final T aValue,
@Nonnull final Predicate aFilter)
{
return aFilter.test (aValue) ? append (sField, aValue) : this;
}
@Nonnull
public ToStringGenerator appendIf (@Nonnull final String sField,
@Nullable final T aValue,
@Nonnull final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? append (sField, aValue) : this;
}
@Nonnull
public ToStringGenerator appendIfNotNull (@Nonnull final String sField, @Nullable final Object aValue)
{
return aValue == null ? this : append (sField, aValue);
}
@Nonnull
public ToStringGenerator appendPasswordIf (@Nonnull final String sField, final BooleanSupplier aFilter)
{
return aFilter.getAsBoolean () ? appendPassword (sField) : this;
}
@Nonnull
public String getToString ()
{
if ((m_nIndex & APPENDED_CLOSING_BRACKET) == 0)
{
m_nIndex |= APPENDED_CLOSING_BRACKET;
m_aSB.append (']');
}
return m_aSB.toString ();
}
/**
* @deprecated Don't call this; Use {@link #getToString()} instead
*/
@Override
@Nonnull
@Deprecated (forRemoval = false)
public String toString ()
{
return getToString ();
}
/**
* Create a {@link ToStringGenerator} for derived classes where the base class
* also uses the {@link ToStringGenerator}. This avoids that the implementing
* class name is emitted more than once.
*
* @param sSuperToString
* Always pass in super.toString ()
* @return Never null
*/
@Nonnull
public static ToStringGenerator getDerived (@Nonnull final String sSuperToString)
{
// We don't need the object if "super.toString" is involved, because in
// super.toString the object is already emitted!
return new ToStringGenerator (null)._appendSuper (sSuperToString);
}
}